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Magnesium-based hydrogen storage alloys have attracted significant attention as promising materials for solid-state hydrogen storage due to their high hydrogen storage capacity, abundant reserves, low cost, and reversibility. However, the widespread application of these alloys is hindered by several challenges, including slow hydrogen absorption/desorption kinetics, high thermodynamic stability of magnesium hydride, and limited cycle life. This comprehensive review provides an in-depth overview of the recent advances in magnesium-based hydrogen storage alloys, covering their fundamental properties, synthesis methods, modification strategies, hydrogen storage performance, and potential applications. The review discusses the thermodynamic and kinetic properties of magnesium-based alloys, as well as the effects of alloying, nanostructuring, and surface modification on their hydrogen storage performance. The hydrogen absorption/desorption properties of different magnesium-based alloy systems are compared, and the influence of various modification strategies on these properties is examined. The review also explores the potential applications of magnesium-based hydrogen storage alloys, including mobile and stationary hydrogen storage, rechargeable batteries, and thermal energy storage. Finally, the current challenges and future research directions in this field are discussed, highlighting the need for fundamental understanding of hydrogen storage mechanisms, development of novel alloy compositions, optimization of modification strategies, integration of magnesium-based alloys into hydrogen storage systems, and collaboration between academia and industry. [ABSTRACT FROM AUTHOR]

Magnesium-based hydrogen storage materials have garnered significant attention due to their high hydrogen storage capacity, abundance, and low cost. However, the slow kinetics and high desorption temperature of magnesium hydride hinder its practical application. Various preparation methods have been developed to improve the hydrogen storage properties of magnesium-based materials. This review comprehensively summarizes the recent advances in the preparation methods of magnesium-based hydrogen storage materials, including mechanical ball milling, methanol-wrapped chemical vapor deposition, plasma-assisted ball milling, organic ligand-assisted synthesis, and other emerging methods. The principles, processes, key parameters, and modification strategies of each method are discussed in detail, along with representative research cases. Furthermore, the advantages and disadvantages of different preparation methods are compared and evaluated, and their influence on hydrogen storage properties is analyzed. The practical application potential of these methods is also assessed, considering factors such as hydrogen storage performance, scalability, and cost-effectiveness. Finally, the existing challenges and future research directions in this field are outlined, emphasizing the need for further development of high-performance and cost-effective magnesium-based hydrogen storage materials for clean energy applications. This review provides valuable insights and references for researchers working on the development of advanced magnesium-based hydrogen storage technologies. [ABSTRACT FROM AUTHOR]

Magnesium-based multicomponent alloys with different compositions, namely Mg60Al20Zn5Cu10Mn5 (Mg60 alloy), Mg70Al15Zn5Cu5Mn5 (Mg70 alloy), and Mg80Al5Cu5Mn5Zn5 (Mg 80) alloys, were prepared using the disintegrated melt deposition technique. The DMD technique is a distinctive method that merges the benefits from gravity die casting and spray forming. This approach facilitates high solidification rates, process yields, and reduced metal wastage, resulting in materials with a fine microstructure and minimal porosity. Their potential as biodegradable materials was assessed through corrosion in different simulated body fluids (SBFs), microstructure, and cytotoxicity tests. It was observed that the Mg60 alloy exhibited low corrosion rates (~× 10−5 mm/year) in all SBF solutions, with a minor amount of corrosive products, and cracks were observed. This can be attributed to the formation of the Mg32(AlZn)49 phase and to its stability due to Mg(OH)2 film, leading to excellent corrosion resistance when compared to the Mg70 and M80 alloys. Conversely, the Mg80 alloy exhibited high corrosion rates, along with more surface degradation and cracks, due to active intermetallic phases, such as Al6Mn, Al2CuMg, and Al2Cu phases. The order of corrosion resistance for the Mg alloy was found to be ASS > HBSS > ABP > PBS. Further, in vitro cytotoxicity studies were carried out using MDA-MB-231 tumor cells. By comparing all three alloys, in terms of proliferation and vitality, the Mg80 alloy emerged as a promising material for implants, with potential antitumor activity. [ABSTRACT FROM AUTHOR]

Concerning various materials in the engineering domain, magnesium alloy-based composites are found to have specific properties. They are prepared with ceramic particles via a liquid stirring process, and oxidation results in porousness. Due to this, this research aims to develop cast magnesium alloy (AZ80), nanocomposite and hybrid nanocomposites via a liquid state stir casting process with an argon atmosphere. It contains 0, 2, 4 and 6 wt% of silicon carbide nanoparticles (SiC) and 6 wt% SiC with 3, 6 and 9 wt% of basalt fibre. The developed cast AZ80 alloy, nano and hybrid nanocomposites are subjected to physical, mechanical and wear behaviour studies, and their results are compared. The composite contained 6 wt% SiC, and 9 wt% BF showed low porosity (1.03%), superior tensile strength (359 ± 7 MPa), elastic modulus (23044.58 ± 230 MPa), strain (2.114 ± 0.01 mm), hardness (121 ± 1.02 HV), coefficient of friction (0.421 ± 0.02) and low impact strength (18.25 ± 0.34 J/mm2) and volumetric wear rate (5.36 ± 0.4 mm3/m) compared to others. [ABSTRACT FROM AUTHOR]

Magnesium-based biomaterials hold remarkable promise for various clinical applications, offering advantages such as reduced stress-shielding and enhanced bone strengthening and vascular remodeling compared to traditional materials. However, ensuring the quality of preclinical research is crucial for the development of these implants. To achieve implant success, an understanding of the cellular responses post-implantation, proper model selection, and good study design are crucial. There are several challenges to reaching a safe and effective translation of laboratory findings into clinical practice. The utilization of Mg-based biomedical devices eliminates the need for biomaterial removal surgery post-healing and mitigates adverse effects associated with permanent biomaterial implantation. However, the high corrosion rate of Mg-based implants poses challenges such as unexpected degradation, structural failure, hydrogen evolution, alkalization, and cytotoxicity. The biocompatibility and degradability of materials based on magnesium have been studied by many researchers in vitro; however, evaluations addressing the impact of the material in vivo still need to be improved. Several animal models, including rats, rabbits, dogs, and pigs, have been explored to assess the potential of magnesium-based materials. Moreover, strategies such as alloying and coating have been identified to enhance the degradation rate of magnesium-based materials in vivo to transform these challenges into opportunities. This review aims to explore the utilization of Mg implants across various biomedical applications within cellular (in vitro) and animal (in vivo) models. [ABSTRACT FROM AUTHOR]

Excellent mechanical strength and biodegradable characteristics of magnesium alloys have sparked considerable interest in orthopedic applications. The utilization of magnesium alloys in orthopedic applications has been restricted due to their brittleness caused by high corrosion rate in biological environments. One of the best techniques for increasing corrosion resistance of these alloys is surface coating. For the first time, the present work aims to dip-coat zein-bioactive glass (BG) nanocomposite on AZ31B magnesium alloy. The alloy surface was also coated by native zein as a control coating. BG nanoparticles required for zein and BG (zein_BG) composite were synthesized by a bio-inspired method using cetyltrimethylammonium bromide (CTAB) as a template. The formation of BG particles was affirmed by FTIR showing characteristic Si-O-Si and Si-O– peaks. Nano-size of BG particles with an average diameter of 6.67 ± 0.06 nm was reported by TEM. SEM micrographs revealed successful deposition of zein and zein_BG coatings on the magnesium alloy surfaces. High-resolution XPS analysis on zein_BG-coated Mg alloy immersed in HBSS revealed the corrosion deposition of Mg(OH)2, MgHPO4.H2O, CaHPO4.H2O, SiO2, MgCO3, and CaCO3 on the substrate surface. More than twofold wettability, 95% adhesion strength and 14-fold increase in surface roughness were reported for zein_BG-coated magnesium alloy compared to the bare surface. Measurements of weight loss in zein and zein_BG-coated alloy substrates in Hanks Balanced Salt Solution (HBSS) for 10 d at 37°C showed a drastic decrease in weight loss of substrates after coating. As a result, zein_BG-coated substrate was observed to possess the maximum protective efficacy (95.99%) against corrosion. Interestingly, electrochemical measurements revealed a vast decrease in corrosion current density (2.41 E−6 A.cm−2) of zein_BG-coated substrate compared to the uncoated substrate (3.04 E−4 A.cm−2). Electrochemical impedance spectra (EIS) confirmed capacitive behavior of zein_BG-coated alloy substrate. These findings demonstrated that simple zein_BG composite dip coating was a successful corrosion-resistant implant coating on magnesium alloy surface for orthopedic applications. [ABSTRACT FROM AUTHOR]

Researchers at Nagoya University in Japan have used artificial intelligence (AI) to discover a new method for understanding dislocations in polycrystalline materials, which are widely used in electronic devices. The AI created a 3D model to identify areas where dislocation clusters were affecting the material's performance. The researchers found that staircase-like structures at the boundaries between crystal grains caused dislocations during crystal growth. This research has the potential to revolutionize the performance of polycrystalline materials and contribute to the creation of innovative materials. [Extracted from the article]

Adjustable ring mode laser beam welding (ARMLBW) has become a promising welding method due to its stable weld quality. In this study, the equation for the distribution of heat flux density of the ring beam was derived, and a combined volumetric heat source model for simulating ARMLBW was proposed. The evolution of the weld pool and keyhole during the welding of AZ31B magnesium alloy using ARMLBW and conventional single laser beam welding (SLBW) laser was compared and analyzed. The results showed that the maximum error in size between the simulated and experimental weld cross-sections did not exceed 10%. Compared to SLBW, the duration of "bubbles" in the weld pool decreased by at least 75% in ARMLBW. The oscillation amplitude of the weld pool and keyhole volume increased by 100%, and the oscillation period was also extended by at least 64%. This is consistent with the experimental reduction in the number of porosity defects (65%), validating the effectiveness of the simulation results. Reducing the oscillation frequency of the weld pool and keyhole, as well as increasing the oscillation amplitude, can result in high-quality welds with fewer porosity defects. Additionally, long and narrow keyholes are more prone to porosity defects in smaller weld pool. The impact of the flowing liquid metal in the weld pool on the keyhole surface is an important factor in the formation of "bubbles," not all of which ultimately become porosity defects. Generally, porosity defects are formed by "bubbles" that have not completely merged with the keyhole and "bubbles" that have not overflowed from the weld pool. The combined action of positive and negative pressure is more likely to cause the formation of porosity defects in smaller weld pool. The formation of humps and depressions on the inner surface of the keyhole is related to the static pressure of the weld pool. [ABSTRACT FROM AUTHOR]

Magnesium and its alloys are advantageous in clinical applications due to their excellent mechanical properties and suitable biological properties. However, due to their high corrosion rate in physiological environments, these alloys' application was limited. Polypyrrole (PPy) coatings were potentiostatically deposited on AZ31 alloy to reduce its corrosion rate in this study. The effect of applied potential and monomer concentration on the coatings' characteristics and properties such as wettability, corrosion resistance, and adhesion strength was studied. The coatings had cauliflower and porous micro-granular morphologies, according to scanning electron microscope images. The thickness and average roughness of the coatings increased from 0.3 to 3.8 µm and 18.3 to 43.7 nm, respectively, as the monomer concentration in the deposition bath was increased from 0.1 to 0.2 M. Increasing the applied potential had the same effect on thickness and roughness. According to the water contact angle (WCA) results, the alloy and all of the PPy coatings were hydrophilic. However, increasing the monomer concentration of the bath and the applied potential increased the WCA of the coatings. The electrochemical behavior of the samples in Ringer's solution was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy. All of the coatings outperformed the bare substrate in terms of corrosion resistance. The corrosion current density of the optimum PPy coating obtained from a bath with 0.2 M pyrrole monomer at 3 V was approximately seven times lower than that of the AZ31 alloy. In the cross-cut adhesion test, this coating also demonstrated the best adhesion to the substrate. [ABSTRACT FROM AUTHOR]

The aluminium industry for ship materials produces waste material that can pollute the environment. To protect the environment from material pollution, the aluminium waste recycling process can be used to develop ship material. This study aims to analyze the physical and mechanical characteristics of aluminium with magnesium, copper, and zinc addition. Several tests, such as chemical composition, tensile, and impact tests, will be conducted to ascertain the mechanical properties of aluminium alloy. Adding alloy material in the range of 0-10% resulted in various alloy element compositions. It can be analyzed that the aluminium contents decreased with the increase of alloy elements. The highest rise in alloy elements can be found in the addition of magnesium than in copper and zinc addition. Moreover, the mechanical tests showed that aluminium casting with magnesium, copper, and zinc additions influenced the mechanical properties of the aluminium alloy. It can be found that tensile strength and modulus of elasticity values improved with the increase of alloy addition. The addition of magnesium has better tensile properties than the addition of copper and zinc. In contrast, the impact resistance decreased with the addition of magnesium, making the alloy more brittle. [ABSTRACT FROM AUTHOR]

In this work, the effect of SiC and Al2O3 nanoparticles and multipass friction stir processing (MPFSP) on the metallurgical properties of AZ91D was carefully investigated and observed a homogenous dispersion of nanoparticles and refined grain size in the processed zone. The presence of the Mg17Al12 intermetallic compound in the MPFSP of AZ91D with SiC and Al2O3 nanoparticles has significant implications for the material's properties. Mg17Al12 is a typical intermetallic phase formed in magnesium alloys and can profoundly affect thermal, microstructural, and mechanical properties. The intermetallic phase can improve the processed region's strength due to its inherent hardness and solid solution strengthening effect, resulting in enhanced tensile properties and hardness. As the FSP passes increased, the tendency for reinforcement agglomeration diminished. Before undergoing MPFSP/(SiC + Al2O3), the base metal AZ91D exhibited an ultimate tensile strength (UTS) of 208.36 MPa and a strain percentage 15.72. After implementing MPFSP/(SiC and Al2O3) on AZ91D, the UTS consistently increased with each FSP pass. This effect was evident at the fourth FSP pass, yielding a higher UTS of 284.35 MPa. In essence, this process facilitated a marked enhancement in the metallurgical properties of AZ91D, signifying the efficacy of the MPFSP approach when combined with reinforcement particles. The hardness value was higher when the indenter engaged with Mg17Al12 than α-Mg. The SZ of 4-pass FSP (Al2O3+SiC)/AZ91D reached a maximum hardness value of 69.37 HV, while single-pass FSP (Al2O3)/AZ91D exhibited a minimum value of 64.89 HV. [ABSTRACT FROM AUTHOR]

• Coatings with Ta 2 O 5 nanoparticles were successfully formed on Mg. • It was found that incorporation of Ta 2 O 5 nanoparticles increases roughness and porosity of the PEO layers contributing into sufficient soft tissue ingrowth in vivo. • The cell morphology indicates good histocompatibility of the obtained coatings and intensive tissue ingrowth. • It was found that incorporation of the Ta 2 O 5 nanoparticles elicits higher rates of apatite layer formation. The present study investigates the physical and chemical characteristics, behavior in vitro and in vivo , and biocompatibility of coatings containing Ta 2 O 5 , which are obtained by plasma electrolytic oxidation (PEO) on MA8 magnesium alloy. The obtained coatings demonstrate in vivo biocompatibility and in vitro bioactivity. Compared to the base PEO coating, the layers containing Ta 2 O 5 facilitate the development of apatite in simulated body fluid, suggesting that the inclusion of nanoparticles improves bioactivity of the coatings. It was found that incorporation of Ta 2 O 5 nanoparticles increases roughness and porosity of the formed layers by increasing particle concentration in electrolytes for the PEO process contributing to sufficient soft tissue ingrowth in vivo. Based on in vivo studies, these coatings also provide favorable tissue response and minimal inflammatory reaction in comparison with the bare magnesium alloy due to protection of living tissues from deleterious corrosion events of magnesium implant such as local alkalization and intense hydrogen evolution. The results obtained in the present study concluded biocompatibility, tissue integration of the PEO coatings containing Ta 2 O 5 nanoparticles making them a promising protective layer for biodegradable magnesium implants. [Display omitted] [ABSTRACT FROM AUTHOR]

• Microstructure, hardness, corrosion rate evolution under solution treatment tracked. • Accelerated characterization via XRD, microscopy, hardness, immersion studies. • Physics-based Machine Learning decodes structure-property correlation. • Grain size and ternary precipitate control crucial for strength-corrosion optimization. [Display omitted] Magnesium alloys are emerging as promising alternatives to traditional orthopedic implant materials thanks to their biodegradability, biocompatibility, and impressive mechanical characteristics. However, their rapid in-vivo degradation presents challenges, notably in upholding mechanical integrity over time. This study investigates the impact of high-temperature thermal processing on the mechanical and degradation attributes of a lean Mg-Zn-Ca-Mn alloy, ZX10. Utilizing rapid, cost-efficient characterization methods like X-ray diffraction and optical microscopy, we swiftly examine microstructural changes post-thermal treatment. Employing Pearson correlation coefficient analysis, we unveil the relationship between microstructural properties and critical targets (properties): hardness and corrosion resistance. Additionally, leveraging the least absolute shrinkage and selection operator (LASSO), we pinpoint the dominant microstructural factors among closely correlated variables. Our findings underscore the significant role of grain size refinement in strengthening and the predominance of the ternary Ca 2 Mg 6 Zn 3 phase in corrosion behavior. This suggests that achieving an optimal blend of strength and corrosion resistance is attainable through fine grains and reduced concentration of ternary phases. This thorough investigation furnishes valuable insights into the intricate interplay of processing, structure, and properties in magnesium alloys, thereby advancing the development of superior biodegradable implant materials. [ABSTRACT FROM AUTHOR]

• Improvement of surface integrity of AZ91 magnesium alloy using liquid nitrogen assisted milling and comparison with conventional dry milling. • Cryogenic milling minimized the machining temperature by about 29%, minimized the alloy surface roughness by about 28% and maximized the microhardness by about 23%. • Compressive residual stresses are generated in cryogenic milled surfaces. • No significant microstructural damages observed from both cryogenic and conventional milling operations. • The optimal process parameters for milling AZ91 alloy under both dry and cryogenic conditions have been identified. Use of magnesium is the need of the hour due to its low density as well as its high strength-to-weight and stiffness-to-weight ratio etc. This study focuses on the effectiveness of liquid nitrogen (LN 2) assisted cryogenic machining on the surface integrity (SI) characteristics of AZ91 magnesium alloy. Face milling using uncoated carbide inserts have been performed under liquid nitrogen (LN 2) assisted cryogenic condition and compared with conventional (dry) milling. Experiments are performed using machining parameters in terms of cutting speeds of 325, 475, 625 m/min, feed rates of 0.05, 0.1, 0.15 mm/teeth and depth of cuts of 0.5, 1, 1.5 mm respectively. Most significant surface integrity characteristics such as surface roughness, microhardness, microstructure, and residual stresses have been investigated. Behaviour of SI characteristics with respect to milling parameters have been identified using statistical technique such as ANOVA and signal-to-noise (S/N) ratio plots. Additionally, the multi criteria decision making (MCDM) techniques such as additive ratio assessment method (ARAS) and complex proportional assessment (COPRAS) have been utilized to identify the optimal conditions for milling AZ91 magnesium alloy under both dry and cryogenic conditions. Use of LN 2 during machining, resulted in reduction in machining temperature by upto 29% with a temperature drop from 251.2 °C under dry condition to 178.5 °C in cryogenic condition. Results showed the advantage of performing cryogenic milling in improving the surface integrity to a significant extent. Cryogenic machining considerably minimized the roughness by upto 28% and maximised the microhardness by upto 23%, when compared to dry machining. Cutting speed has caused significant impact on surface roughness (95.33% – dry, 92.92% – cryogenic) and surface microhardness (80.33% – dry, 82.15% – cryogenic). Due to the reduction in machining temperature, cryogenic condition resulted in compressive residual stresses (maximum σ ║ = -113 MPa) on the alloy surface. Results indicate no harm to alloy microstructure in both conditions, with no alterations to grain integrity and minimal reduction in the average grain sizes in the near machined area, when compared to before machined (base material) surface. The MCDM approach namely ARAS and COPRAS resulted in identical results, with the optimal condition being cutting speed of 625 m/min, a feed rate of 0.05 mm/teeth, and a depth of cut of 0.5 mm for both dry and cryogenic environments. [Display omitted] [ABSTRACT FROM AUTHOR]

• Polymer-coated Mg-0.4Zn wires are suitable for biomedical applications. • Grain boundary Zn segregation can improve yield strength of thin Mg-Zn wires. • Zn alloying is more beneficial than Mg purification for low-alloyed Mg. • Surface quality and cleaning play a crucial role in degradation of implants. • Surface of hydrogen bubbles is a preferential site for bone tissue formation. Magnesium is an excellent material in terms of biocompatibility and its corrosion products can serve as an active source for new bone formation. However, localized corrosion and H 2 generation limit the potential of Mg-based implants. Utilizing low-alloyed Mg-Zn wires can strongly reduce problems with large H 2 bubbles and improve the mechanical properties considerably while maintaining excellent long-term biocompatibility. Acidic pickling and a polymer coating can be effectively used to lower the rate of in vivo degradation. In this work, microstructural, mechanical, and in vitro characterization of 250 µm and 300 µm extruded wires made from ultra-pure Mg, commercially pure Mg, Mg-0.15Zn, Mg-0.4Zn and Mg-1Zn was performed. Additionally, Mg-0.4Zn wires together with a variant coated with a copolymer of l -lactide and ε-caprolactone were tested in vivo on artificially damaged Wistar rat femurs. Based on the observed Mg-induced osteogenesis, polymer-coated Mg wires with a small addition of Zn are a perspective material for bone-support applications, such as cerclage and fixation wires. [Display omitted] [ABSTRACT FROM AUTHOR]

• The review emphasizes the potential of Mg alloys in lightweight structures and the evolution of FSP for Mg alloys and MMCs in the 21st century. • It covers novel fabrication methods, reinforcement strategies, machine and tool design parameters, material characterization, and integration with other methods for enhanced properties. • FSP offers simultaneous refinement, homogenization, and densification of microstructures, resulting in high strength and improved surface characteristics. • Challenges include the need for further study on pin profiles, process parameters, and mono and hybrid composites. It is recommended that future research should focus on material flow and reinforcement impact on temperature distribution, among many more. • Despite challenges, FSP has the potential to enhance Mg alloys and MMCs in engineering applications, presenting ongoing progress and potential advancements. Rising concerns about climate change drive the demand for lightweight components. Magnesium (Mg) alloys are highly valued for their low weight, making them increasingly important in various industries. Researchers focusing on enhancing the characteristics of Mg alloys and developing their Metal Matrix Composites (MMCs) have gained significant attention worldwide over the past decade, driven by the global shift towards lightweight materials. Friction Stir Processing (FSP) has emerged as a promising technique to enhance the properties of Mg alloys and produce Mg-MMCs. Initially, FSP adapted to refine grain size from the micro to the nano level and accelerated the development of MMCs due to its solid-state nature and the synergistic effects of microstructure refinement and reinforcement, improving strength, hardness, ductility, wear resistance, corrosion resistance, and fatigue strength. However, producing defect-free and sound FSPed Mg and Mg-MMCs requires addressing several variables and their interdependencies, which opens up a broad range of practical applications. Despite existing reviews on individual FSP of Mg, its alloys, and MMCs, an attempt has been made to analyze the latest research on these three aspects collectively to enhance the understanding, application, and effectiveness of FSP for Mg and its derivatives. This review article discusses the literature, classifies the importance of Mg alloys, provides a historical background, and explores developments and potential applications of FSPed Mg alloys. It focuses on novel fabrication methods, reinforcement strategies, machine and tool design parameters, material characterization, and integration with other methods for enhanced properties. The influence of process parameters and the emergence of defects are examined, along with specific applications in mono and hybrid composites and their microstructure evolution. The study identifies promising reinforcement materials and highlights research gaps in FSP for Mg alloys and MMCs production. It concludes with significant recommendations for further exploration, reflecting ongoing advancements in this field. [Display omitted] [ABSTRACT FROM AUTHOR]

• A computational thermo-fluid and CALPHAD for L-PBF of Mg alloys was introduced. • Capabilities of thermos-fluid models within Mg alloying system were verified. • Effect of thermos-physical material properties on melt pool dynamics were studied. • Higher vapor pressure increases melt pool depth and possibility of porosities. • Higher viscosity and freezing range exacerbate keyhole and porosity formation. • The proposed model shows promise for designing alloys for L-PBF. Multi-physics thermo-fluid modeling has been extensively used as an approach to understand melt pool dynamics and defect formation as well as optimizing the process-related parameters of laser powder-bed fusion (L-PBF). However, its capabilities for being implemented as a reliable tool for material design, where minor changes in material-related parameters must be accurately captured, is still in question. In the present research, first, a thermo-fluid computational fluid dynamics (CFD) model is developed and validated against experimental data. Considering the predicted material properties of the pure Mg and commercial ZK60 and WE43 Mg alloys, parametric studies are done attempting to elucidate how the difference in some of the material properties, i.e., saturated vapor pressure, viscosity, and solidification range, can influence the melt pool dynamics. It is found that a higher saturated vapor pressure, associated with the ZK60 alloy, leads to a deeper unstable keyhole, increasing the keyhole-induced porosity and evaporation mass loss. Higher viscosity and wider solidification range can increase the non-uniformity of temperature and velocity distribution on the keyhole walls, resulting in increased keyhole instability and formation of defects. Finally, the WE43 alloy showed the best behavior in terms of defect formation and evaporation mass loss, providing theoretical support to the extensive use of this alloy in L-PBF. In summary, this study suggests an approach to investigate the effect of materials-related parameters on L-PBF melting and solidification, which can be extremely helpful for future design of new alloys suitable for L-PBF. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Twinning in Mg alloys arises due to challenges in slip along the c-axis, impacting orientations differently at varying CRSS. • Many factors like GBs, texture, and stress states influence the twinning nucleation, propagation, and growth in Mg alloys. • Dislocation interactions and thermal effects affect twinning activation in Mg alloys, while annealing treatments may stabilize TBs. • Anomalous behavior of ET in Mg-RE alloys suggests RE elements alter c/a ratio, favoring smaller Burger vector at TBs. • CT and DT in Mg alloys promote DRX but pose risks as sources of voids and cracks. Twinning is widely recognized as an effective and cost-efficient method for controlling the microstructure and properties of wrought magnesium (Mg) alloys. Specifically, twins play a crucial role in initiating dynamic recrystallization (DRX), while twin regions experience rapid recrystallization during static recrystallization (SRX). The activation of twinning can lead to changes in lattice orientation, significantly impacting the final texture in Mg alloys. The active roles of twinning are influenced by various factors during the activation process, and the mobility of twin boundaries (TB) can be amplified by stress effects, dislocation interactions, and thermal effects. Conversely, annealing treatments that involve proper segregation or precipitation on TBs serve to stabilize them, restraining their motion. Events such as segregation may also alter the twinning propensity in Magnesium-rare earth (Mg-RE) alloys. While {10–11} contraction twins (CT) and {10–11}-{10–12} double twins (DT) can promote dynamic recrystallization (DRX), they also pose a risk as potential sources of voids and cracks. Additionally, understanding the nucleation and growth mechanisms of twinning is crucial, and these aspects are briefly reviewed in this article. Considering the factors mentioned above, this article summarizes the recent research progress in this field, shedding light on advancements in recent eras. [ABSTRACT FROM AUTHOR]

• The review encompasses the processing techniques, heterogeneous microstructures, and mechanical properties, with a specific emphasis on the strengthening and toughening mechanisms of heterostructured Mg alloys. • Based on the concept of heterogeneous structure design, the construction of different heterostructures in Mg alloys can obtain high strength while maintaining good ductility. • Based on the challenges encountered in the design and fabrication of heterostructured Mg alloys, some urgent issues and future research directions for heterogeneous Mg alloys are suggested. In recent years, a new class of metallic materials featuring heterogeneous structures has emerged. These materials consist of distinct soft and hard domains with significant differences in mechanical properties, allowing them to maintain high strength while offering superior ductility. Magnesium (Mg) alloys, renowned for their low density, high specific strength, exceptional vibration damping, and electromagnetic shielding properties, exhibit tremendous potential as lightweight and functional materials. Despite their advantageous properties, high-strength Mg alloys often suffer from limited ductility. However, the emergence of heterogeneous materials provides a fresh perspective for the development of Mg alloys with both high strength and ductility. This article provided a fundamental overview of heterostructured materials and systematically reviewed the recent research progress in the design of Mg alloys with strength-ductility balance based on heterostructure principles. The review encompassed various aspects, including preparation methods, formation mechanisms of diverse heterostructures, and mechanical properties, both within domestic and international contexts. On this basis, the article discussed the challenges encountered in the design and fabrication of heterostructured Mg alloys, as well as the urgent issues that require attention and resolution in the future. [ABSTRACT FROM AUTHOR]

• Lightweight Mg-Ta-Al composites with both excellent radiation-shielding (17 times of traditional Mg-based alloys) and great mechanical property (54–76 MPa for the interface bonding strength) were successfully developed using hot rolling process. • The sheets possess a special transitional zone including an obvious inter-diffusion Mg-Al interface, unique micro-corrugated Ta-Al interface, and a thin Al film with thickness of about 10 µm. • The Mg-Al interface formation primarily depended on Mg/Al atoms diffusion basing point defects movement, while the Ta-Al interface formed via strain-induced micro-interlock basing close-packed planes slipping at high temperature plastic deformation process. A novel lightweight, radiation-shielding Mg-Ta-Al layered metal-matrix composite (LMC) was successful designed by doping the extremely refractory metal (Ta) into Mg sheets. These Mg-based LMCs sheets shows excellent radiation-dose shield effect, about 145 krad·a−1, which is about 17 times of traditional Mg alloy, while its surface density is only about 0.9 g·cm−2, reducing by 60% than that of pure Ta. The quantitate relationship between radiation-dose and the materials' thickness was also confirmed to the logistic function when the surface density is in the range of 0.6–1.5 g·cm−2. Meantime, the rolling parameters, interface microstructure and mechanical properties in both as-rolled and annealing treated samples were evaluated. The sheets possess a special dissimilar atoms diffusion transitional zone containing an obvious inter-diffusion Mg-Al interface and the unique micro-corrugated Ta-Al interface, as well as a thin Al film with a thickness of about 10 µm. The special zone could reduce the stress concentration and enhance the strength of Mg-Ta-Al LMCs. The interface bonding strength reaches up to 54–76 MPa. The ultimate tensile strength (UTS) and yield strength (TYS) of the Mg-Ta-Al sheet were high to 413 MPa and 263 MPa, respectively, along with an elongation of 5.8%. The molecular dynamics (MD) analysis results show that the two interfaces exhibit different formation mechanism, the Mg-Al interface primarily depended on Mg/Al atoms diffusion basing point defects movement, while the Ta-Al interface with a micro-interlock pining shape formed by close-packed planes slipping during high temperature strain-induced deformation process. [ABSTRACT FROM AUTHOR]

• Low-energy PEO coatings were grown on Mg–Li alloy in presence of ionic liquid. • The corrosion resistance of low-energy PEO coating with ionic liquid was enhanced. • The role of ionic liquid was demonstrated by molecular dynamics simulation. • Influence of ionic liquid on the formation of LePEO coating was discussed. A low-energy plasma electrolytic oxidation (LePEO) technique is developed to simultaneously improve energy efficiency and anti-corrosion. Ionic liquids (1‑butyl‑3-methylimidazole tetrafluoroborate (BmimBF 4)) as sustainable corrosion inhibitors are chosen to investigate the corrosion inhibition behavior of ionic liquid (ILs) during the LePEO process for LA91 magnesium–lithium (Mg–Li) alloy. Results show that the ionic liquid BmimBF 4 participates in the LePEO coating formation process, causing an increment in coating thickness and surface roughness. The low conductivity of the ionic liquid is responsible for the voltage and breakdown voltage increases during the LePEO with IL process (LePEO-IL). After adding BmimBF 4 , corrosion current density decreases from 1.159 × 10−4 A·cm−2 to 8.143 × 10−6 A·cm−2. The impedance modulus increases to 1.048 × 104 Ω·cm−2 and neutral salt spray remains intact for 24 h. The superior corrosion resistance of the LePEO coating assisted by ionic liquid could be mainly attributed to its compact and thick barrier layer and physical absorption of ionic liquid. The ionic liquid-assisted LePEO technique provides a promising approach to reducing energy consumption and improving film performance. [ABSTRACT FROM AUTHOR]

• Oscillating laser-arc hybrid welding of AZ31B magnesium alloy was carried out. • Beam oscillation was beneficial to inhibit the pore formation. • The grain growth was promoted by secondary recrystallization. • Σ13b boundaries with {101 ̅2} tensile twins were promoted by beam oscillation. • The elongation rate was 12.8% higher than the weld without beam oscillation. Oscillating laser-arc hybrid welding of AZ31B magnesium alloy was carried out, the effects of beam oscillation parameters on pore inhibition, microstructure, grain boundary characteristics and tensile properties were investigated. The results showed that the pore formation can be inhibited with oscillating frequency higher than 75 Hz and radius smaller than 0.5 mm. The columnar grains neighboring the fusion line can be broken by the beam oscillation behavior, while the grain growth was promoted with the increase of frequency or radius. It should be noted that the coincidence site lattice (CSL) boundaries were mainly Σ13b and Σ29 boundaries, which were contributed by {10 1 ¯ 2} tensile twins and {11 2 ¯ 2} compression twins, respectively. The total fraction of CSL boundaries reached maximum at radius of 0.25 mm and frequency of 75 Hz, which was also confirmed as the optimized parameters. In this case, the elongation rate increased up to 13.2%, 12.8% higher than that of the weld without beam oscillation. Finally, the pore formation and inhibition mechanisms were illustrated according to the state of melt flow and keyhole formation, the abnormal growth was discussed basing on secondary recrystallization, and the relationship among the pore formation, grain size, boundary characteristics and weld toughness were finally established. [Display omitted] [ABSTRACT FROM AUTHOR]

• The high rolling temperature would impede the DRX occurrence for these final-rolled sheets. • The reduction of the volume fraction of this β phases led to the highest peak-aging hardness in R-450 °C sheet. • The precipitate chains in R-385 °C + A sheets were beneficial for strength and elongation. • The traditional precipitation characteristic in R-450 °C + A sheet was bad for elongation but good for strength. • The peak-aging R-450 °C sheet showed the highest strength, i.e. UTS of 518±17 MPa and YS of 438±18 MPa. In this investigation, a high-strength Mg-12Gd-1.0Er-0.5Zr (wt.%) alloy sheet was produced by hot extrusion (HE) and subsequent hard-plate rolling (HPR) at different temperatures. The results indicate that the microstructures of these final-rolled sheets are inhomogeneous, mainly including coarse deformed grains and dynamic recrystallized (DRXed) grains, and the volume fraction of these coarse deformed grains increases as the rolling temperature increases. Thus, more DRXed grains can be found in R-385 °C sheet, resulting in a smaller average grain size and weaker basal texture, while the biggest grains and the highest strong basal texture are present in R-450 °C sheet. Amounts of dynamic precipitation of β phases which are mainly determined by the rolling temperature are present in these sheets, and its precipitation can consume the content of Gd solutes in the matrix. As a result, the lowest number density of β phase in R-450 °C sheet is beneficial to modify the age hardening response. Thus, the R-450 °C sheet displays the best age hardening response because of a severe traditional precipitation of β' (more) and β Η / β Μ (less) precipitates, resulting in a sharp improvement in strength, i.e. ultimate tensile strength (UTS) of ∼ 518 ± 17 MPa and yield strength (YS) of ∼ 438±18 MPa. However, the elongation (EL) of this sheet reduces greatly, and its value is ∼ 2.7 ± 0.3%. By contrasting, the EL of the peak-aging R-385 °C sheet keeps better, changing from ∼ 4.9 ± 1.2% to ∼ 4.8 ± 1.4% due to a novel dislocation-induced chain-like precipitate which is helpful to keep good balance between strength and ductility. [ABSTRACT FROM AUTHOR]

• The structure of Mg(OH) 2 /LDH coating is tailored by roughness of Mg alloy surface. • FPG coating on Mg substrate with the lowest roughness has denser and thicker structure. significantly improving the corrosion resistance. • FPG composite coating has the best corrosion resistance and good biocompatibility. Corrosion-resistant and biocompatible films were fabricated on AZ91D Mg alloy substrates by varying their roughness levels using metallographic preparation and subsequent hydrothermal procedures. The coated films comprised a mixed structure of Mg(OH) 2 and Mg-Al layered double hydroxides (LDH) and exhibited excellent compactness. Coating film thickness increased with decreasing surface roughness. Corrosion resistance was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy. Metallographic pretreatment influenced the chemical activity of the Mg alloy surface and helped modulate the dissolution rate of the Mg 17 Al 12 phase during the hydrothermal procedure. With decreasing roughness of the Mg substrate, the Al3+ concentration gradually increased, accelerating the in-situ formation of the Mg(OH) 2 /LDH composite coating and improving its crystallinity. A thick and dense Mg(OH) 2 /LDH coating was synthesized on the Mg substrate with the least roughness, substantially improving the corrosion resistance of the AZ91D alloy. The lowest corrosion current density ((5.73 ± 2.75) × 10−8 A·cm−2) was achieved, which was approximately three orders of magnitude less than that of bare AZ91D. Moreover, the coating demonstrated biocompatibility with no evident cytotoxicity, cellular damage, and hemolytic phenomena. This study provides an effective method for preparing coatings on Mg alloy surfaces with excellent corrosion resistance and biocompatibility. [ABSTRACT FROM AUTHOR]

• The low-cycle fatigue life of T6 alloy is longer than that of T4 alloy. • T4 alloy shows cyclic hardening fatigue behavior, but T6 alloy shows cyclic softening. • Fatigue cracks propagate along PSBs in T4 alloy, but fatigue cracks propagate along grain boundaries in T6 alloy. • Compared with T4 alloy, the enhanced pyramidal slip in T6 alloy plays an important role to accommodate plastic deformation. The low-cycle fatigue behavior of solutionized (T4) and aged (T6) WE43 magnesium alloys was studied at room temperature. The total strain amplitudes (Δε t /2) were 0.4%, 0.5%, 0.6%, 0.7% and 1.0%. Detailed microstructure evolution was characterized by scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). The results showed that plastic strain amplitude decreased with the increasing cycle number in T4 alloy, which is due to the dense persistent slip bands (PSBs) and dynamic precipitates hindering dislocation slip. In contrast, the plastic strain amplitude increases gradually in T6 alloy, which is attributed to the enhanced activation of pyramidal slip. The low-cycle fatigue life of T6 alloy with larger fatigue ductility coefficient is longer than that of T4 alloy. The Coffin-Manson model can accurately predict the fatigue life of T4 and T6 alloys compared to Jahed-Varvani (JV) energy model. For T4 alloy, the fatigue damage mechanism was dominated by basal slip. For T6 alloy, the enhanced pyramidal slip plays an important role to accommodate plastic deformation. [ABSTRACT FROM AUTHOR]

• Effect of parameters on defects, microstructure and tensile properties was studied. • The microstructure changes from large grains with lamellae to equiaxed grains. • The bimodal-grained microstructure leads to better mechanical properties. • The yield drop phenomenon is observed in SLMed Mg-Nd-Zn-Zr alloy. • The average grain size, not the pores, determines the mechanical properties in SLM. Mg–3Nd–0.2Zn–0.4Zr (NZ30K, wt.%) alloy is a new kind of high-performance metallic biomaterial. The combination of the NZ30K Magnesium (Mg) alloy and selective laser melting (SLM) process seems to be an ideal solution to produce porous Mg degradable implants. However, the microstructure evolution and mechanical properties of the SLMed NZ30K Mg alloy were not yet studied systematically. Therefore, the fabrication defects, microstructure, and mechanical properties of the SLMed NZ30K alloy under different processing parameters were investigated. The results show that there are two types of fabrication defects in the SLMed NZ30K alloy, gas pores and unfused defects. With the increase of the laser energy density, the porosity sharply decreases to the minimum first and then slightly increases. The minimum porosity is 0.49 ± 0.18%. While the microstructure varies from the large grains with lamellar structure inside under low laser energy density, to the large grains with lamellar structure inside & the equiaxed grains & the columnar grains under middle laser energy density, and further to the fine equiaxed grains & the columnar grains under high laser energy density. The lamellar structure in the large grain is a newly observed microstructure for the NZ30K Mg alloy. Higher laser energy density leads to finer grains, which enhance all the yield strength (YS), ultimate tensile strength (UTS) and elongation, and the best comprehensive mechanical properties obtained are YS of 266 ± 2.1 MPa, UTS of 296 ± 5.2 MPa, with an elongation of 4.9 ± 0.68%. The SLMed NZ30K Mg alloy with a bimodal-grained structure consisting of fine equiaxed grains and coarser columnar grains has better elongation and a yield drop phenomenon. [ABSTRACT FROM AUTHOR]

Continuous casting processes of metals are the most common in terms of obtaining the input material for metal working processes such as wire drawing. One of the issues regarding the process is maintaining the proper temperature preventing cast rod surface oxidation. Experimental work using a laboratory furnace was conducted to verify the parameters determined using finite element method simulations of continuous casting of CuMg alloys. Furthermore, as the alloys are fully novel and not produced or researched on a large scale, they were subjected to microstructural analysis and basic property tests in order to determine their electrical conductivity, density, hardness, and impact toughness. Additionally, pure copper was cast with the same laboratory furnace and the same parameters to function as a point of reference. The obtained results were also compared to commercial materials used for electrical purposes, such as brasses and bronzes. The obtained results proved that the mechanical properties of tested alloys are 2–2.5 times higher than pure copper. Also, the tested materials exhibit lower densities than commercial brass or bronze alloys and their mechanical properties are similar, while electrical conductivity is significantly higher and, thus, they may be used as a material for electrical applications. [ABSTRACT FROM AUTHOR]

Hot--extruded AZX611Mg alloy was multi--directionally forged under decreasing--temperature conditions (dMDFed) and followed by room--temperature MDFing (rMDFing). Coarse initial grains were gradually fragmented by dynamic recrystallization during dMDFing and ultrafine--grained structure was homogeneously developed over the cumulative strain of ΣΔε = 4.8. Additional rMDFing contributed to further grain fragmentation due to kinking and mechanical twinning. Nevertheless, coarse precipitates in the as--hot--extruded samples and newly formed fine precipitates during dMDFing impeded twinning. The achieved grain size appeared rather larger than that of the dMDFed AZ61Mg alloy. While mechanical properties were drastically improved by simple dMDFing or rMDFing, the combined processes of dMDFing and rMDFing were not so effective to induce additional strengthening. This was attributed to complicatedly combined effects of impediment of twinning by precipitates to grain fragmentation and fracture caused by stress concentration at around precipitates/matrices. [ABSTRACT FROM AUTHOR]

This research addresses the demand for biodegradable orthopedic implants by enhancing magnesium-based alloys. Biodegradable magnesium alloy-based hybrid composites, produced through squeeze casting, incorporate titanium (Ti) and hydroxyapatite (HA) particles to improve microstructure, hardness, and compressive strength. The Mg–3Zn/1Ti/1.5HA composite exhibits a 13% increase in hardness and a 15.8% enhancement in compression strength compared to the base MZA alloy. In corrosion assessments at 216 h, MZA/1Ti/1.5HA shows a 21% lower corrosion rate than MZA/1Ti/0.5HA and a 10% lower rate than MZA/1Ti/1HA. The refined grain structure and formation of protective oxide layers resulting from Ti and HA incorporation contribute to enhanced corrosion resistance. Cytotoxicity assessments reveal excellent biocompatibility, with the Mg–3Zn/1Ti/1.5HA composite exceeding an 80% relative growth rate due to the formation of bone-like apatite layer, surpassing MZA/1Ti/0.5HA and MZA/1Ti/1HA. These findings underscore the potential of squeeze-casted magnesium alloy-based hybrid composites, particularly Mg–3Zn/1Ti/1.5HA, as promising orthopedic implant biomaterials. [ABSTRACT FROM AUTHOR]

The objective of this work was to analyze the in vitro and in vivo tests of a novel Mg-based biodegradable alloy—Mg-0.5%Ca—with various amounts of Zn (0.5, 1, 1.5, 2.0, and 3.0 wt.%). In terms of in vitro biocompatibility, MTT and Calcein-AM cell viability assays, performed on the MG-63 cell line through the extract method, revealed that all five alloy extracts are non-cytotoxic at an extraction ratio of 0.025 g alloy per mL of cell culture medium. In the in vivo histological analysis, Mg-0.5Ca-1.5Zn demonstrated exceptional potential for stimulating bone remodeling and showed excellent biocompatibility. It was observed that Mg-0.5Ca-0.5Zn, Mg-0.5Ca-1.5Zn, and Mg-0.5Ca-3Zn displayed good biocompatibility. Furthermore, the histological examination highlighted the differentiation of periosteal cells into chondrocytes and subsequent bone tissue replacement through endochondral ossification. This process highlighted the importance of the initial implant's integrity and the role of the periosteum. In summary, Mg-0.5Ca-1.5Zn stands out as a promising candidate for bone regeneration and osseointegration, supported by both in vitro and in vivo findings. [ABSTRACT FROM AUTHOR]

This study investigated the effects of solution heat treatment and multi-directional forging (MDF) on the microstructure, mechanical, and corrosion properties of an Mg–2Zn–0.2Ag alloy. Microstructural characterization by field emission scanning electron microscopy indicated that the as-cast material consists of some MgZn2 and Ag-rich MgZn precipitates. These silver-rich MgZn precipitates were entirely and partially dissolved after the solution treatment and MDF, respectively. In addition, the grain size of the as-cast alloy increased by 86% and decreased by 43% after solution heat treatment and MDF, respectively. The ultimate shear strength of the as-cast material increased by 25% and reached 149.5 MPa after MDF processing, while it did not change significantly after solution treatment. The obtained results indicated that the corrosion layer formed on the samples consists of an inner layer (magnesium hydroxide) and an outer layer (phosphate compounds). Based on the corrosion tests, it was found that solution heat treatment and MDF could significantly improve the corrosion resistance of the as-cast Mg–2Zn–0.2Ag. The corrosion resistance (Rp) obtained from the electrochemical impedance spectroscopy (EIS) test exhibited enhancements of 119% and 152% after heat treatment and MDF processes, respectively. This improvement in corrosion resistance was attributed to the higher stability of the outer layer in both solution-treated and MDF-processed samples, compared to the as-cast material. The results of cell studies also indicated a significant improvement in the cell viability of the solution-treated Mg–2Zn–0.2Ag alloy sample compared with pure Mg. [ABSTRACT FROM AUTHOR]

Marine structures are constantly exposed to the corrosive effects of seawater, making effective corrosion protection crucial for their longevity and performance. Sacrificial anodes, commonly made of zinc, aluminum, or magnesium alloys, are widely employed to mitigate corrosion by sacrificing themselves to protect the steel structures. However, the selection and implementation of sacrificial anode materials present various challenges that need to be addressed. This paper explores the challenges associated with sacrificial anode materials for steel structures and provides potential solutions. To overcome these challenges, the paper proposes solutions such as using advanced alloy compositions, protective coatings, hybrid anode systems, and improved design considerations. Furthermore, the importance of monitoring techniques to assess the performance and remaining lifespan of sacrificial anodes is emphasized. Several case studies and experimental findings are discussed to illustrate the effectiveness and limitations of sacrificial anode materials based on zinc alloys, aluminum alloys, and magnesium alloys. The paper highlights the need for ongoing research and development efforts to address the evolving demands of corrosion protection in marine environments. [ABSTRACT FROM AUTHOR]

In this work, the bioabsorbable materials, namely fibroin, polylactide acid (PLA), magnesium, and magnesium oxide are investigated for their application as transient, resistive temperature detectors (RTD). For this purpose, a thin‐film magnesium‐based meander‐like electrode is deposited onto a flexible, bioabsorbable substrate (fibroin or PLA) and encapsulated (passivated) by additional magnesium oxide layers on top and below the magnesium‐based electrode. The morphology of different layered RTDs is analyzed by scanning electron microscopy. The sensor performance and lifetime of the RTD is characterized both under ambient atmospheric conditions between 30°C and 43°C, and wet tissue‐like conditions with a constant temperature regime of 37°C. The latter triggers the degradation process of the magnesium‐based layers. The 3‐layers RTDs on a PLA substrate could achieve a lifetime of 8.5 h. These sensors also show the best sensor performance under ambient atmospheric conditions with a mean sensitivity of 0.48 Ω/°C ± 0.01 Ω/°C. [ABSTRACT FROM AUTHOR]

Metal alloy matrix composites are generally lightweight structural materials with a high strength-to-weight ratio. They can be extensively used in various fields of modern engineering applications, such as aerospace and automotive components and biomedical engineering. This study focuses on the development and characterization of lightweight metal alloy matrix composites for industrial applications, with a particular emphasis on magnesium (Mg) alloys as a replacement for aluminum-based alloys. Mg alloys offer significant weight advantages, being 33% lighter than aluminum and 75% lighter than steel, making them highly desirable for use in various engineering fields. In the present study, Mg (AZ91) alloy reinforced with x-Si3N4 composites (x = 0, 1, 3, 5, 7, 9 wt.%) were fabricated using a liquid state process. The AZ91/x-Si3N4 composites were evaluated through physical, mechanical, wear, and microstructural characterization. The experimental results, supported by statistical analysis, demonstrated that the incorporation of Si3N4 particles amplified the mechanical properties, wear resistance, and porosity of the composites. However, the presence of the reinforced particles resulted in reduced forgeability and elongation, limiting certain deformation characteristics. The existence of the reinforced particles within the composites was confirmed through SEM analysis, providing visual evidence of their distribution and interaction within the Mg alloy matrix. Finally, it was concluded that the implication of the study could be sought for the light structural parts of aerospace, automotive, biomedical, and prosthetic applications. [ABSTRACT FROM AUTHOR]

Magnesium alloys, because of their excellent strength-to-weight ratio, are increasingly used in many industries. When used in external elements, the key factor is to provide adequate anticorrosion protection. High-temperature, cured-powder coatings are widely used to protect most metals, but their use on magnesium alloys is difficult as a result of the instability of the magnesium substrate at elevated temperatures. Another problem is ensuring the proper adhesion of the organic coating to the magnesium substrate. This paper presents the procedure for the synthesis of a duplex coating on AZ91 magnesium alloy. The topcoat was a powder coating based on acrylic resin, the main ingredient of which was glycidyl methacrylate. Because of the presence of epoxy groups, the coating was cured using ultraviolet (UV) radiation (low-temperature technology). The conversion subcoating was produced by plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte. The synthesized coating system was tested, among others, for microscopic (SEM), adhesive (mesh of cuts), and anticorrosion (EIS). The duplex PEO/UV-curable powder coating showed very good adhesion to the metal and increased the anticorrosion properties of the magnesium substrate, compared to the powder coating produced directly on the magnesium alloy and on an alternative conversion coating (synthesized in the process of chemical zircon phosphating). [ABSTRACT FROM AUTHOR]

The emergence of biodegradable stents addresses the limitations of the long-term presence of permanent bare metal stents in the human body. Following implantation, these stents can significantly reduce the occurrence of chronic complications such as inflammation and thrombosis, thus becoming a mainstream approach in the treatment of interventional cardiovascular diseases. Currently, the materials used for biodegradable stents are typically polymers. However, the inherent properties of the materials dictate that polymer stents exhibit lower mechanical performance and biocompatibility. Magnesium alloy materials, on the basis of their biodegradability, exhibit superior mechanical performance when compared to polymers, possessing the potential to address this issue. However, the presence of stress concentration in the stent structure necessitates further designs and mechanical performance analyses of magnesium alloy stents. In this work, a biodegradable stent based on WE43 alloy is designed. The stent incorporates the micro-protrusion structure to enhance the mechanical performance. Furthermore, to evaluate the clinical applicability of the stent, the mechanical performance of the biodegradable magnesium alloy stent is conducted through finite element analysis (FEA). The results show that the maximum equivalent stress in all four aspects is below the ultimate tensile strength of 370 MPa for the WE43 magnesium alloy, demonstrating excellent mechanical performance. Additionally, after crimping and expansion, the radial support strength and radial support force reached 780 mN/mm and 1.56 N, respectively. Compared to the advanced reported stent structures, the radial support strength and radial support force are enhanced by 13% and 47%, respectively. Additionally, flexibility analysis indicated that the flexibility of the stent design in this study is improved by a factor of 9.76, ensuring the stent's capability to navigate through complex vasculature during implantation. [ABSTRACT FROM AUTHOR]

An alternative to the existing method of processing secondary magnesium raw materials by remelting in a salt furnace can be distillation separation into volatile metals (Mg, Zn and Cd), low-volatile metals (Al, Mn and Zr) and rare earth elements. The separation of metals may be tracked based on phase diagrams where the field boundaries of the vapor–liquid equilibrium are plotted. Due to the fact that Mg, Zn and Cd have comparable saturated vapor pressures, the possibility of the distillation separation of Mg–Zn and Mg–Cd systems using full state diagrams including the melt–vapor phase transition boundaries were determined in this work. The boundaries of these systems were calculated based on the partial values of saturated vapor, determined by the boiling point method, and presented in the form of temperature–concentration dependencies with the indicated boundaries. The field boundaries were calculated (L + V) at atmospheric pressure (101.33 kPa) and in vacuum (1.33 kPa and 0.7 kPa,) supposing the implementation of the process. The possibility of the separate extraction of zinc and cadmium from magnesium was considered using complete phase diagrams including the boundaries of the melt–steam phase transition. When considering the boundaries of the vapor–liquid equilibrium in the binary systems Mg–Zn and Mg–Cd, it was established that it is impossible to separate metals in one "evaporation–condensation" cycle in a vacuum of 1.33 and 0.7 kPa. The problem is caused by the small size of the fields (L + V) at the temperature, which suggests processes of the re-evaporation of the condensate from the previous distillation stage. The separation of zinc and cadmium from liquid alloys with magnesium under equilibrium conditions requires several repetitions of the condensate distillation process. In non-equilibrium conditions, the real processes will require a larger number of conversions. This implies the expediency of the joint evaporation of magnesium with zinc and cadmium and the use of condensate for additional charging to liquid magnesium, and the remainder of the distillation, where volatile metals such as Al, Mn, Zr and rare earth elements will be concentrated, should be directed to the preparation of ligatures for special magnesium-based alloys. [ABSTRACT FROM AUTHOR]

The European Green Deal poses a two-pronged challenge for the automotive industry: migrating to solutions based on light structures, requiring lightweight concepts and light materials, while at the same time avoiding dependence on the importation of these advanced materials. Aluminium alloys are lightweight and cost-effective materials that can successfully meet the requirements of many structural applications; however, their production requires bauxite and other Critical Raw Materials (CRMs), such as Si and Mg. Aluminium alloys are fully recyclable, but scrap is usually contaminated and its use is related to an increment of impurities, tramp elements and undesired inclusions. Traditionally, the use of secondary alloys has been restricted to low-performance applications. The present work analyses the effect that the use of scrap has on the quantity of inclusions present in the alloy and on other properties relevant for material processing. This study was carried out using common alloys associated with three of the most common aluminium processes used in the car manufacturing industry: high-pressure die casting (HPDC) (AB-43500), extrusion (6063) and sheet metal forming (5754 and 6181). The reference alloys were mixed with different levels of scrap (0, 20, 40, 60, 80 and 100%), with an aim to keep the chemical composition as unaffected as possible. The inclusion level of the alloy was characterized using the Prefil Footprinter® test. In addition, the obtained materials, after being cast in an open mould, were subjected to metallographic characterization. Relevant properties were measured to assess the processability of the alloys for the corresponding transforming process using the flowability test for the HPDC alloy and high-temperature compression for the extrusion alloys. The results obtained suggest that the number of inclusions present in the melt highly increase with the amount of scrap used to produce the alloy. These inclusions are also related to a significant loss of flowability, but do not have a noticeable impact on microstructure. [ABSTRACT FROM AUTHOR]

In this investigation, the effects of different annealing temperatures (180, 200, 220, 240, 260, and 280 °C) on the microstructure evolution and properties of an extruded Mg–2.0Zn–1.0Y–0.5Zr (wt%) magnesium alloys were determined. Optical microscopy (OM), scanning electron microscopy (SEM), immersion corrosion, electrochemical corrosion experiments, and tensile testing were performed. Research has found that combining hot extrusion with subsequent low-temperature annealing significantly improves the strength, plasticity, and corrosion resistance of alloys due to grain refinement and a reduced dislocation density. The alloy was completely recrystallized at an annealing temperature of 240 °C for 4 h after solid solution extrusion, and the grains were fine and uniform, demonstrating the best comprehensive properties. Its corrosion rate, ultimate tensile strength, yield strength, and elongation were 0.454 ± 0.023 mm/y, 346.7 ± 8.9 MPa, 292.4 ± 6.9 MPa, and 19.0 ± 0.4%, respectively. The corrosion mechanism of the specimens under extruded and annealed conditions was analyzed. After annealing at 240 °C for 4 h, the dislocation and bimodal grain structure of the samples were almost eliminated, resulting in uniform and fine grains, which were conducive to the formation of a more uniform and denser oxide film, thus improving the corrosion resistance of the alloy. [ABSTRACT FROM AUTHOR]

Aviation-integrated communication equipment is integral to modern aircraft to ensure its performance and safety. The heat dissipation problems of equipment have become increasingly prominent for the high electronic integration and system power consumption. To solve the above problem, the heat dissipation performance of aviation-integrated communication equipment based on graphene films is deeply studied. This paper establishes a three-dimensional model of aviation-integrated communication equipment to simulate the distribution of temperature fields. The influence between aluminum alloy and graphene films on the surface of magnesium alloy on the heat dissipation performance of aviation-integrated communication equipment is studied. The simulation results show that the heat balance time of the equipment using graphene films on the surface of magnesium alloy is reduced from 3600 s to 800 s, representing an approximately 77.78% improvement; the measured equipment exhibited a reduction in its overall thermal equilibrium temperature, decreasing from 68.1 °C to 66.3 °C, representing an improvement of approximately 2.64%. [ABSTRACT FROM AUTHOR]

Pure magnesium and Mg-(0.2-0.9 at%) Y rolled sheets were subjected to three-point bending tests to individually investigate the effects of texture and yttrium addition on bending deformation behavior. Yttrium addition increased bending yield stress in both Specimen TR with the neutral plane parallel to the ND (normal direction of the rolled sheets) plane and Specimen TN with the neutral plane perpendicular to the ND plane, resulting from the increase in critical resolved shear stresses (CRSSs) for basal slip and f10-12g twinning with yttrium addition. Bending ductility increased with increasing yttrium addition until 0.5 at% yttrium addition, and then decreased at 0.9 at% yttrium addition in Specimen TN. On the other hand, bending ductility increased until 0.9 at% yttrium addition in Specimen TR since non-basal slip activities increased with increasing yttrium addition. Since the neutral plane in Specimen TN with 0.9 at% yttrium addition moved more to the center than that in Specimen TN with 0.5 at% yttrium addition, resulting in the higher tensile strain at the tension side. Therefore, the bending ductility in 0.9 at% yttrium addition was lower than that in 0.5 at% yttrium addition. [ABSTRACT FROM AUTHOR]

The current study attempted to introduce nano-aluminium oxide (Al2O3) particles into ZE41 alloy via friction stir processing (FSP). The effect of these nano-Al2O3 particles on the mechanical and tribological characteristics of ZE41 alloy is investigated. The results of microstructural studies revealed the uniform distribution of Al2O3 particles and substantial grain refinement in the stir zone by FSP. Enhanced microhardness was observed in the processed region due to the grain refinement and the occurrence of regularly distributed Al2O3 particles. The wear resistance was also seen increased with the incorporation of the Al2O3 particles. Moreover, the effect of FSP parameters on the successful incorporation of nano-Al2O3 particles in ZE41 alloy without any defect is also realised. [ABSTRACT FROM AUTHOR]

In the manufacturing sector, welding has long been a popular method of combining materials. Hence, there has been a lot of research in this area, leading to evolution of conventional welding techniques. These developments widened its feasibility enabling the process to be functional in diverse crucial applications. A detailed review of various research efforts carried out in the field of welding provides an ideal repository which can effectively help identify various research gaps. This paper intends to throw light on the following aspects of welding: a detailed description of different fabrication methods involved in fusion and solid-state welding processes, weld performance evaluation on the basis of mechanical properties, microstructure, corrosion, wear and fatigue behaviour followed by a brief summary of various applications. The mechanical properties and microstructures of various commercially viable alloys like steel, DSS, Ti-6Al-4 V, Al- Mg alloy, AZ31, AA6061, Al-Zn-Mg-Cu and Ni-base super alloys have been discussed in detail. Various mechanisms which influenced the changes in microstructure and resulting mechanical behaviours have been discussed. The inferences obtained as a result of microstructural, mechanical, corrosion and wear property analysis have been correlated to understand major areas of application. The extensive data compiled in this study aims to give readers valuable insights and inferences on a vast topic, which promises great scope for development in the future. [ABSTRACT FROM AUTHOR]

In this study, we aim to enhance the corrosion and wear resistance of AZ31 magnesium alloy using electrophoretic deposition (EPD) technology to apply a hydrophobic polytetrafluoroethylene (PTFE) coating. Polyethyleneimine (PEI) serves as a charged dispersant, facilitating uniform deposition of PTFE particles on the alloy surface. Results demonstrate a significant reduction in corrosion current density (from 67.5 μA/cm2 to 5.2 μA/cm2) and improved wear resistance (wear volume decreased from 0.24167 mm3 to 0.00167 mm3) in a 3.5 wt% NaCl solution compared to uncoated alloy. Moreover, the friction coefficient of the coated sample decreases. These findings underscore the potential of nano-PTFE coatings prepared via EPD in enhancing AZ31 magnesium alloy's corrosion and wear resistance, providing a foundation for future protective coating design and optimization. [ABSTRACT FROM AUTHOR]

Fibre metal laminates (FMLs) are the most interesting composite materials of the past decade. They possess the properties of both polymer composites and metallic alloys. However, there is a problem with corrosion when the outer layers are made of aluminium or magnesium. The electrochemical changes that occur during the corrosion process and the mechanisms associated with the corrosion phenomenon are still being investigated. Recently, self-healing phenomena have emerged as a useful approach to prevent corrosion. However, there is limited research on the combination of FMLs and self-healing layers. Therefore, the main purpose of this article is to evaluate the self-healing ability of a magnesium/PEO layer based on microcapsules in a corrosion environment. It was observed that the corrosion mechanism in magnesium alloys is very complex. However, the use of a barrier layer with PEO treatment and microcapsules yielded positive anti-corrosion results. The FML samples were subjected to a 6-week corrosion test, and the addition of microcapsules to the layers showed positive results. In contrast, the samples without microcapsules exhibited intergranular corrosion. In the future, comprehensive tests using self-healing microcapsules in FMLs could greatly enhance their anti-corrosion properties and improve the integrity of the structure. [ABSTRACT FROM AUTHOR]

With the increasing attention received by lightweight metals, numerous essential fields have increased requirements for magnesium (Mg) alloys with good room-temperature and high-temperature mechanical properties. However, the high-temperature mechanical properties of commonly used commercial Mg alloys, such as AZ91D, deteriorate considerably with increasing temperatures. Over the past several decades, extensive efforts have been devoted to developing heat-resistant Mg alloys. These approaches either inhibit the generation of thermally unstable phases or promote the formation of thermally stable precipitates/phases in matrices through solid solution or precipitation strengthening. In this review, numerous studies are systematically introduced and discussed. Different alloy systems, including those based on Mg–Al, Mg–Zn, and Mg–rare earth, are carefully classified and compared to reveal their mechanical properties and strengthening mechanisms. The emphasis, limitations, and future prospects of these heat-resistant Mg alloys are also pointed out and discussed to develop heat-resistant Mg alloys and broaden their potential application areas in the future. [ABSTRACT FROM AUTHOR]

The strength of the joints in the Mg/Ti laser welding is difficult to meet the requirement because of the metallurgical incompatibility. This study investigates the influence of microgroove width on the diffusion of molten Mg and the mechanical properties of joints by laser welding Ti6Al4V and AZ31B, employing femtosecond lasers to fabricate microgrooves on the surface of Ti alloys. The optimal contact angle of 56.4° is achieved at the microgroove width of 100 μm because the leading and trailing edges of the microgroove texture can stimulate the formation of the microriveted structure, facilitating the fluidity of the liquid AZ31B. The joint's tensile–shear capability is increased to 2449.9 N, which is 2.8 times stronger compared to joints without microgroove textures, when using a microgroove width of 100 μm and a laser power of 52%. The numerical simulation of the laser welding process was implemented to analyze the temperature field and the fluid characteristics within the melt pool. In the results, it is shown that the microgroove enhanced the material exchange at the interface and accelerated the interfacial reaction, which stimulates the formation of Ti–Al and Mg–Al intermetallic compounds at the central interface of the joint and enhances the Mg/Ti metallurgical bonding. [ABSTRACT FROM AUTHOR]

2D materials have exhibited great potential for applications in anticorrosion nanocoatings. However, the nanocoating of prefocused graphene shows "corrosion‐promoting activity" due to its high conductivity. Metal oxide nanosheets obtained by delaminating layered oxides have been another attractive candidate. This study demonstrates a water‐based Ca2Nb3O10 (CNO) ink spray coated on magnesium alloys to form a continuous coating without complex functionalization and structural control. The composite coating of Ca2Nb3O10 (CNO) and polydopamine (PDA) is fabricated by combining spray‐ and dip‐coating methods. The surface composition and microstructure of the as‐prepared coatings are characterized by X‐ray diffractometry, Fourier transform infrared, X‐ray photoelectron spectroscopy, scanning electron microscopy, and energy‐dispersive spectrometry. The anticorrosion performance of the composite coating is evaluated by potentiodynamic polarization, electrochemical impedance spectroscopy, and salt spray tests. The electrochemical results show that the CNO/PDA heterostructure coating provides an enhanced corrosion inhibition efficiency (99.62%) with a corrosion current density of 5.49 × 10−7 A cm−2, three orders of magnitude lower than bare AZ31. The immersion tests before and after heat treatment and salt spray tests indicate that the composite coating has good stability and long‐term anticorrosion performance. Solution‐processed nanocoating and extensible materials design provide a green and facile route to anticorrosion nanotechnology for industrial demands. [ABSTRACT FROM AUTHOR]

In cold-chamber high pressure die casting (HPDC), some pre-solidification occurs in the shot sleeve prior to being injected into the die cavity. Here, we study the effects of pre-solidification on the development of microstructure and defects in the HPDC of magnesium alloy AE44 (Mg–4Al–4RE–0.2Mn, wt pct, where RE are mixed La and Ce) and on subsequent tensile properties. Samples with a high fraction of pre-solidification contained both externally solidified crystals (ESCs) and cold flakes, which also induced large pockets of positive macrosegregation. Variations in the morphology and length scale of α -Mg grains and eutectic Al 11 RE 3 are discussed in terms of the different cooling conditions for each microstructural feature using a grain morphology map for α -Mg. A high fraction of pre-solidification resulted in a small decrease in yield stress due to the larger microstructural length scale, and a substantial decrease in ultimate tensile strength and ductility due to the presence of a non-bonded interface between cold flakes and the surrounding material. The results provide insights into microstructure formation in the HPDC of AE44 and highlight the importance of controlling the extent of pre-solidification that is injected into the die cavity. [ABSTRACT FROM AUTHOR]

The purpose of this project is to build an accurate prediction model for the maximum thinning rate of the truncated cone made of magnesium alloy AZ31B by single-point incremental forming. A truncated cone's thickness distribution is analyzed using ABAQUS. Orthogonal experiments and supplementary data were performed as training samples within the maximum refinement rate obtained from the finite element (FE) results. Back-propagation (BP) neural network is established by taking into account tool diameter, initial sheet thickness, and forming angle as input responses, and maximum thinning rate as output responses, and nine hidden layers are involved. The results showed that the incidence of process parameters on the maximum thinning rate of the truncated cone is in the order of forming angle, initial thickness of sheet, and diameter of tool from large to small; The correlation coefficient of BP neural network model training R = 0. 9 9 3 4 4. The test results and FE results contrast, and the average error rate of the maximum thinning rate is only 0.97%. The results indicate that the model is reliable and accurate for the prediction of incremental forming, and it is a useful reference value. [ABSTRACT FROM AUTHOR]