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5356 aluminum alloy welding wire is widely used in automotive, aerospace, and marine, due to its excellent corrosion resistance, high strength-to-weight ratio, and excellent weldability. The properties of aluminum alloys are primarily determined by their microstructure. This study investigates the microstructure evolution, mechanical properties, and texture of 5356 aluminum alloy welding wire produced using the continuous casting direct rolling (CCDR) method. The results show that continuous rolling led to an increased generation of dislocations in the matrix, and dynamic recovery plays an important role in reducing dislocation density. As a result of dynamic recovery, the microstructures of 3RPs consist of extensive deformed grains and numerous substructures. The continuous casting direct rolling textures are characterized to be cube and shear textures. After 10 rolling processes, the 5356 aluminum alloy welding wire shows a highest tensile strength of 365 MPa with a lowest elongation of 8.8%. This research provides theoretical guidance to produce high-performance 5356 aluminum alloy welding wires, paving the way for their more efficient and reliable applications. [ABSTRACT FROM AUTHOR]

This study investigates the microstructural behavior of laboratory-produced Al–Mg–Si(X)–Mn aluminum alloys, focusing on the influence of varying Si content during biaxial hot tensile testing. Alloys with Si contents of 0.7%, 0.9%, and 1.3% were subjected to biaxial deformation at temperatures of 200 °C, 300 °C, and 400 °C. Using digital image correlation analysis, the impact of Si content on microstructural evolution under biaxial tensile loading was analyzed. Force–displacement analysis revealed a consistent inverse relationship between temperature and the maximum force required to initiate strain. At the temperature of 200 °C, the Al–Mg–Si(1.3)–Mn alloy required a maximum force of 1500 N, while at the temperature of 400 °C this force decreased to 900 N. The degree of anisotropy varied, with higher Si alloys exhibiting increased resistance to deformation in the transverse direction. In particular, the Al–Mg–Si(1.3)–Mn alloy showed pronounced strain anisotropy, with large major true strain φ1 values reaching up to 0.32 at 400 °C, compared to 0.26 at 300 °C and 0.2 at 200 °C. Microstructural analysis using electron backscatter diffraction (EBSD) and energy dispersive X-ray spectrometry (EDS) showed minimal changes at low temperatures, while increased dislocation density and grain boundary distortion were observed at elevated temperatures. The β-Mg2Si precipitates, influenced by Si content and temperature, significantly affected the mechanical properties. In the Al–Mg–Si(0.7)–Mn alloy, precipitates were predominantly 1–3 µm in diameter, whereas in the Al–Mg–Si(1.3)–Mn alloy, precipitates grew to 4–8 µm at higher Si content. These findings provide critical insights into the mechanical response and deformation mechanisms of aluminum alloys under biaxial tensile conditions, essential for optimizing material performance in engineering applications. [ABSTRACT FROM AUTHOR]

The twin-roll casting (TRC) of light metal alloys, in particular aluminium and magnesium alloys, represents a promising technology for the production of lightweight components thanks to its short process chain and promising combinations of properties. In the production of strip products, TRC is susceptible to a number of defects due to the coupled process steps of casting and forming, which prevent its use for more complex alloy combinations in the field. In this review, the defects in TRC of light metal alloys will be summarized and discussed. In addition to a basic classification of the defect types and definition of these, the formation mechanisms and avoidance strategies will be discussed. Special focus is placed on centreline segregation defects and surface bleeds, which occur in a large number of investigations in the literature. Effective avoidance strategies are defect-specific, but are mostly due to the combination of the plant design of the TRC process, the TRC parameters or the use of alloying elements to influence the solidification process. [ABSTRACT FROM AUTHOR]

The importance of comprehensive multiscale characterisation in advancing our understanding of engineering materials is undeniable but remains a challenging pursuit. Combining complimentary microstructure characterisation techniques, including transmission electron microscopy, electron backscatter diffraction and dark-field X-ray microscopy (DFXM), the formation of deformation microstructures is investigated in presence of shearable and non-shearable hardening precipitates in an industrial aluminium alloy (AA) 2024 (Al–Cu–Mg family). The alloy was used in naturally aged T3 (with shearable co-clusters and Guinier–Preston–Bagaryatsky (GPB) zones) and peak-hardened T8 (with non-shearable S-phase precipitates) states. After cold rolling with thickness reductions varying from 25 to 60% (or corresponding von Mises strain from 0.33 to 1.06), the T8 state revealed a higher sub-boundary density with slightly smaller mean disorientation angle, as compared to those in the T3 state. At a von Mises strain of 0.33, the T8 state exhibited higher long-range orientation gradients, as compared to the T3 state, for higher strain orientation gradients in T3 surpass those in T8 state. With DFXM, distinct 3D substructures are shown, revealing ellipsoidal sub-grains in the T8 state and pancake-like sub-grains in the T3 state. Moreover, the stored energy induced by cold rolling is higher for the T8 state. These results indicate different deformation microstructures, formed in the same AA2024 but hardened by shearable and non-shearable precipitates. [ABSTRACT FROM AUTHOR]

In this study, the effect of zirconium addition (1, 1.5, 2 wt%) on the microstructural morphology and wear behavior of Al-Si-Cu-Ni-Mg alloys, known as light metals in which intermediate phases solidify rapidly at high temperatures, was investigated. The study aimed to obtain a stronger material by modifying the Al81Si12Cu4Ni2Mg alloy. It was observed that the Zr added to the alloy was homogeneously distributed throughout the samples. Aluminum and silicon formed compounds with zirconium (Al3Zr and ZrSi2), leading to the formation of a thinner and stronger structure. With the heat treatment applied to the aluminum alloys, the structure became more ductile. Additionally, as a result of Zr addition, microhardness increased, and wear values improved. [ABSTRACT FROM AUTHOR]

The phenomenon of rapid phase transition induced by electroshock treatment (EST) in metals has been widely observed, but its kinetic process is rarely quantitatively analyzed. In this work, the dissolution of the second phases in the Al–Zn–Mg–Cu alloys caused by EST was investigated using scanning electron microscopy and transmission electron microscopy. It was found that EST can sufficiently dissolve nanoscale precipitates, Al2CuMg phases and the short rod-shaped dispersed phases in the alloys. Additionally, a non-isothermal dissolution kinetics model has been proposed to depict the dissolution process of the second phase in the Al–Zn–Mg–Cu alloys during EST. The evolution laws and key factors of the second phase dissolution during EST were obtained by numerically solving these models. The solving results are basically consistent with the phenomena monitored in the experiment. These models are expected to be adopted to illustrate the phase transition induced by EST in other metal materials. [ABSTRACT FROM AUTHOR]

Aluminum alloy is widely used in modern manufacturing industry but whose deformation when under certain regime of loading rates or temperature involves prominent Portevin–Le Chatelier (PLC) effect. In the present work the PLC effect in AA5052 aluminum alloy under different loading rates has been characterized via combined usage of digital image correlation (DIC) and acoustic emission (AE) techniques. Under the loading rates considered, different types of PLC bands have been found to yield distinct distribution of stress drops. The spatiotemporal evolution of the PLC bands at low loading rate may be accessible by both the DIC and AE techniques while those at high loading rates are accessible only by the AE technique. All the results may support that the PLC bands are nucleated rather than continuously propagating at high loading rates, which is in contrast to the conventionally held views. [ABSTRACT FROM AUTHOR]

High-performance conductors are essential for economically and environmentally sustainable ways of electricity transfer in modern infrastructure, manufacturing and transportation, including electric vehicles. This report reviews the aluminum conductors, their fundamentals, classification and utilization markets, focusing on metallurgical characteristics of present commercial solutions and the strategy of future development directions. The inherent features of aluminum, both beneficial and detrimental, for electrical engineering are emphasized along with alloying concepts that provide the accelerated decomposition of matrix solid solution to minimize the electron scattering. Development activities are assessed of new generation of aluminum conductors that in addition to alloying utilize novel processing techniques such as ultra-fast crystallization, severe plastic deformation and complex thermomechanical treatments aiming at grain reduction to nanometer scale, crystallographic texture control and grain boundary engineering. Transition metals and rare earths are considered as the promising alloying candidates for high-strength conductors having superior thermal stability with extra importance given to immiscible systems of Al–Ce, Al–La and Al–Y along with multiply additions, combined to generate the synergy effects. The composites with cladding configuration and particulate reinforcement including via carbon-type strengtheners are discussed as the effective solutions of advanced conductors. A variety of strategies that aim at overcoming the strength–conductivity trade-off in conductor materials are presented throughout the report. [ABSTRACT FROM AUTHOR]

This study investigates the potential of employing ceramic particles (CrC, NbC, and TaC) and their combinations to enhance several properties of AA6061 aluminum alloy during friction stir processing (FSP). FSP greatly enhances the reduction in the grain size compared to the original metal. Adding ceramic particles to the material strengthens the resistance to grain growth; thus, FSP significantly reduced grain size compared to the base metal by an average of 91.98%. In particular, composites containing TaC and a combination of CrC and TaC have the smallest grain size, possibly due to the combined impacts of these materials. Nevertheless, there were difficulties in the dispersion of particles, as they tended to be distributed randomly during FSP. Adding ceramic particles can significantly decrease friction compared to the alloy without reinforcement, but the extent of the decrease depends on the type and amount of ceramic particles added. Hybrid composites consisting of CrC and TaC have the most minimal friction coefficient. This hybrid also demonstrated exceptional mechanical properties, with increased stiffness by 34.7% and shear strength by 34.1% compared to the base alloy. Microhardness was significantly enhanced by up to 55.90% with reinforcements, particularly in the CrC + TaC hybrid and TaC composites. The microhardness is improved substantially by including reinforcements, with the hybrid CrC + TaC composites and TaC demonstrating the most substantial gains. The results indicate that adding ceramic particles, specifically CrC and TaC, dramatically enhances the wear resistance, mechanical strength, and microstructural characteristics of the AA6061 aluminum alloy. [ABSTRACT FROM AUTHOR]

The damage mechanisms of ductile fracture under shear loading of an aluminum alloy 2198T8R were studied using flat thin-sheet samples. One sample was loaded until 85% of the failure displacement and then unloaded, and another one was loaded up to failure. To overcome the inherent shortcomings of nanotomography concerning the investigation of flat samples, synchrotron nano-laminography was applied to the pre-loaded sample and provided structural information down to the nanometer scale, allowing ductile damage nucleation and evolution to be studied. The damage features, including flat cracks and intermetallic particle-related damage, were visualized in 3D from the highly-deformed shear band region. Using nano-laminography, no nano-voids were found. The damaged shear ligament was also observed after polishing via destructive correlative scanning electron microscope (SEM) and electron back-scatter diffraction (EBSD) which suggests that the detrimental flat cracks were both intergranular and transgranular. The flat cracks were related to highly-deformed bands. No nano-voids could be found using SEM analysis. Fractography on the second broken sample revealed that the flat cracks contained hardly observable nanometer-sized dimples. The final coalescence region was covered by sub-micrometer-sized dimples, inside which dispersoid particles were present. The fact that no nano-void was found for the pre-deformed sample implies that the nucleation, growth and coalescence of these sub-micrometer-sized voids occur at late stages of the loading history. [ABSTRACT FROM AUTHOR]

In order to inhibit the corrosion of ADC12 aluminum alloy caused oxalic acid in engine coolant, corrosion inhibitor technology is usually used because of its simple operation, low cost, no impact on metal heat dissipation, and effectively suppressing metal corrosion at a lower concentration. In this paper, the corrosion inhibition, long-term and adsorption mechanisms of humic acid (HA) on ADC12 aluminum alloy were studied using electrochemical testing, surface analysis techniques, and theoretical calculations. The results showed that HA was a mixed corrosion inhibitor that followed the Langmuir adsorption model and belonged to physical chemical mixed adsorption. The corrosion inhibition efficiency of HA was the highest at a concentration of 1500 ppm and enhanced with the extension of soaking time. After soaking for 72 h, the corrosion inhibition efficiency of HA reached its maximum (92.7%), indicating that HA had a good long-term corrosion inhibition effect. HA had a high adsorption energy on the surface of ADC12 aluminum alloy, and HA molecules adsorbed on its surface through the carboxyl groups linked to N atom to form a protective corrosion inhibitor film, effectively inhibiting its corrosion. [ABSTRACT FROM AUTHOR]

Nanocomposites containing impermeable two-dimensional materials are attracting considerable attention for their ability to shield metals from corrosion. Incorporating m-aminophenyltrimethoxysilane functionalized niobium nitride (NbN) into a coating matrix can bolster the barrier effect owing to its remarkable chemical and thermal stability. When integrated into graphitic carbon nitride (GCN) within polyurethane (PU), functionalized NbN enhances corrosion protection and imparts fire-retardant properties. Utilizing electrochemical techniques in chloride-rich environments, the protective efficacy of aluminum coated with polyurethane containing varying proportions of functionalized NbN/GCN was investigated. Electrochemical impedance spectroscopy measurements demonstrated improved coating resistance (Rcoat: 5.65 × 1011 Ω cm2) for PU/functionalized NbN/GCN, even after 600 h of electrolyte exposure. Furthermore, the resulting PU composite exhibited superior flame-retardant capabilities, manifesting significant reductions in peak heat release rate, total heat release, and total smoke production compared to pure PU. Featuring a water contact angle of 165°, the newly developed PU/functionalized NbN/GCN coating showcased exceptional water repellency. In terms of mechanical properties such as adhesion strength and hardness, PU/functionalized NbN/GCN demonstrated favorable characteristics within the PU substrate, maintaining structural integrity even after prolonged immersion. Consequently, the PU/functionalized NbN/GCN nanocomposite presents itself as a promising coating component for aerospace applications. [ABSTRACT FROM AUTHOR]

In order to improve the accuracy of the corrosion fatigue life prediction model for the 7050 aluminum alloy, this study presents a corrosion fatigue life prediction model based on back-propagation (BP) neural network optimized by improved grey wolf optimization (IGWO) algorithm that takes into account different sampling orientations and stress magnitudes. The model determines the mapping relationship between corrosion fatigue life, sample direction, and stress level. It also compares the improved grey wolf optimization-backpropagation (IGWO-BP) prediction error with three other models: BP, particle swarm optimization-back propagation (PSO-BP), and genetic algorithm-backpropagation (GA-BP). The IGWO-BP model's performance measures are as follows: a determination coefficient (R2) of 0.9740, a mean absolute error (MAE) of 0.0479, a root mean square error (RMSE) of 0.0596, and a mean absolute percentage error (MAPE) of 0.9443%. For both the training and test sets, the predicted results are within an error margin of 1.5 times. When compared with the conventional BP neural network, the R2 of IGWO-BP is increased by 5.69%, and the RMSE, MAE, and MAPE of IGWO-BP are the smallest, reduced by 26.24, 26.19, and 26.72%, respectively. [ABSTRACT FROM AUTHOR]

Effects of heat treatment on the microstructure and performance of laser-welded joint for the novel heat-resistant aluminum alloy Al–12Ce–0.4Sc were studied. The results show that heat treatment has little effect on the tensile properties of welded joints at room temperature but exhibits a significant effect on the creep properties at high temperature of 300 ℃. The microhardness distribution in the fusion zone is uniform, with a value significantly higher than that of the aluminum base in the base material, but lower than that of the large blocky Al11Ce3 phase. Fractures occurred in the base material during the tensile tests at both room temperature and 300 ℃ high temperature for all joints. The elongation during the tensile test at 300 °C high temperature of the joint welded by cast base material (CA-LW) was approximately twice as high as that of the joint with post-heat treatment welded by cast base material (CA–LW–HT). The CA–LW–HT joint exhibited the best creep resistance with a steady-state creep rate of 3.2 × 10–8 s−1 at 300 ℃ and 55 MPa, which was two orders of magnitude lower than that of the CA–LW joint. A significant reduction in grain size and change in the form of the precipitated phases in the fusion zone were identified as the primary reasons for higher microhardness and strength in the fusion zone than in the base material. The grain size in the fusion zone was less than 1/10 of that in the base material, and large blocky primary Al11Ce3 in the base material almost completely disappeared after the welding process, as the microstructure transformed into eutectics of primary α-Al and nanoscale Al11Ce3/Al. Mild Sc enrichment observed at the Al11Ce3/Al matrix interface in the fusion zone significantly contributed to the maintenance of outstanding high-temperature performance in the fusion zone. [ABSTRACT FROM AUTHOR]

The study systematically examined how Mn impacts the precipitates and mechanical properties of 6082 aluminum alloy during the peak state of artificial aging following various natural aging durations, elucidating the underlying mechanisms. It is found that α-Al(Mn,Fe)Si precipitated during homogenization is less in amount in the alloy with lower Mn content, resulting in the less consumption of Si and a lower real Mg/Si ratio to create a relatively Si-rich environment in matrix. The Si-rich environment promotes the nucleation of the precipitates, so that the low Mn alloy precipitates more and finer precipitates in the artificial aging process, and has higher strength than the high Mn alloy. Additionally, it is also found that with the increase of natural aging time, the precipitates of 6082 aluminum alloy are significantly coarsening, and the alloy with lower Mn content can better resist the coarsening process of the precipitates, so that the strength of the alloy decreases more slowly than that of higher Mn alloys, and the negative effects of natural aging are lighter. [ABSTRACT FROM AUTHOR]

Lightweight strategy is essential for the development of transportation vehicles and aerospace industries. As a type of lightweight material, high-strength aluminum alloys are limited to service temperatures below 200 °C due to the rapid coarsening of strengthening nano-precipitates, which cannot satisfy the increasing demands of practical applications. High-temperature applications beyond 250 °C become the bottle-neck problem of Al alloys. In this paper, we review existing literature on the improvement of high-temperature performance of aluminum alloys by stabilizing nano-precipitates. On the basis of atomic-scale microstructure regulation, several design strategies, such as interface segregation, co-precipitation, core/shell structure, and interstitial ordering, have been proposed, resulting in the development of a number of heat-resistant Al alloys for use at 300–400 °C. Moreover, the fundamental theories of solid-state phase transformation, especially precipitation aging and coarsening, are correspondingly advanced on the frontiers of science. [ABSTRACT FROM AUTHOR]

With development of present energy-saving society, lightweight and green development in the automotive and aerospace industries have put forward urgent demands for heat-resistant cast aluminum alloys. Present cast aluminum alloys are of lightweight and have excellent mechanical properties when serving in ambient environment. However, when serving at temperatures of 200–300 ℃ or even higher, the alloys inevitably soften and the high-temperature mechanical properties decline rapidly, hardly meeting the requirements for high-performance equipments. This paper summarizes the development process of classic heat-resistant aluminum alloys, especially the microstructural characteristics of heat-resistant cast aluminum alloys in the past decade, and reviews the current microstructure tuning strategies of heat-resistant aluminum alloys from the aspects of intrinsic heat resistance of the second phases, phase interface modification, diffusion-controlled phase transition, grain boundary stabilization and composite material design. Finally, we propose the prospects for the future development of heat-resistant aluminum alloys. [ABSTRACT FROM AUTHOR]

Al alloys and aluminum matrix composites (AMCs) are characterized by high specific strength, high specific modulus, and low density. As one of the most promising advanced lightweight materials, Al alloys and AMCs are widely used in high-speed railway, aerospace, defense, and other cutting-edge fields. However, with the urgent demand for lighter and more complex structures in these high-tech fields, traditional processing methods have shown huge limitations, such as long manufacturing process, low material utilization, restricted design and structure of parts. Fortunately, the rapid development of additive manufacturing technology in recent years has greatly expanded the flexibility of design and manufacturing. As a representative technology of metal additive manufacturing, laser powder bed fusion (LPBF) has outstanding advantages such as high accuracy, high material utilization and short production cycle. LPBF of Al alloys and AMCs is an effective method for producing complex and lightweight structural parts, however, at the meantime, it also faces huge challenges. In this article, the current research status of the LPBF processed Al alloys and AMCs are reviewed with main focus on powder preparation, LPBF technology and subsequent treatments. [ABSTRACT FROM AUTHOR]

Microalloying has been an important method in aluminum alloy development for decades. Large number of papers have shown that the addition of trace element Erbium (Er) can effectively improve the comprehensive properties of aluminum alloys. Similar with the trace element Scandium (Sc), addition of trace element Er in aluminum alloys could form nano-sized L12-ordered Al3Er precipitates, which was coherent with the Al matrix. However, the dispersion precipitation strengthening effect of Al3Er was more significant than that of Al3Sc, at the same atomic content. In the case of the addition of both Er and Zr, core–shell-structured Al3(Er, Zr) precipitates formed instead of Al3Er precipitates. Those thermally-stable nanosized precipitates could significantly refine the grain size, retard the recrystallization, improve the mechanical properties and corrosion resistance. This paper reviewed several typical Er-containing microalloyed commercial aluminum alloys, like 2xxx (Al–Cu) alloys, 4xxx (Al–Si) alloys, 5xxx (Al–Mg) alloys, 7xxx (Al–Zn–Mg–Cu) alloys, as well as selective laser melting aluminum alloys. [ABSTRACT FROM AUTHOR]

The special wettability of superhydrophobic aluminum alloys has a broad applied foreground in important industrial fields, such as aviation, automobiles, and ships. However, the microstructures of superhydrophobic surfaces are easily destroyed, causing them to lose superhydrophobicity, which seriously restricts the application of superhydrophobic surfaces. To solve this problem, we developed a simple and low-cost fabrication method by the blasting and chemical deposition of Ni and P to process robust micro/nano-composite structures on an aluminum alloy material and then obtained a superhydrophobic nickel–phosphorus–aluminum surface (SHP-NiP-Al) with a water contact angle of 163° and a water rolling angle of 3° through low surface energy modification. The prepared SHP-NiP-Al had an excellent self-cleaning performance and antifouling property. In addition, it showed great mechanical robustness and chemical stability performance in the sand impact, blade scratch, and acid/base solution tests. It also demonstrated good corrosion resistance performance. Electrochemical corrosion tests indicated that the corrosion resistance of SHP-NiP-Al was better than that of the original aluminum. Moreover, SHP-NiP-Al could collect the water from the fog environment. This method is helpful for the practical use of superhydrophobic aluminum alloy surfaces. [ABSTRACT FROM AUTHOR]

To improve the wear resistance of 6061 aluminum alloys, we reported the fabrication of Fe–Al coatings by laser surface alloying with mixed Fe and Al powders. The alloyed coatings mainly consisted of Fe4Al13, FeAl, Fe3Al and α-Al phases. Due to its high specific gravity, the Fe-rich melt segregated at the bottom of the molten pool during the laser process, and special microstructures characterized by a bright white stripe at the interfacial zone were formed. Additionally, the nonuniform exothermic reactions occurring along the width of the interfacial zone resulted in the formation of a rough sawtooth interface. The typical microstructures from the top layer to the interfacial zone of the alloyed coatings were investigated to explore the formation and solidification processes of the molten pool. Additionally, the microhardness of the coatings markedly improved with increasing Fe concentration in the mixed powders, reaching 720 HV0.2. Moreover, a 92.3% reduction in the volume loss of the 70Fe–30Al coating compared with that of the substrate significantly enhanced the wear resistance. [ABSTRACT FROM AUTHOR]

We propose pathways to produce high-strength thermal resistant Mg-doped Al–Zr-based conductors to be manufactured in the form of ultrafine-grained wires via deliberate thermomechanical treatment, including aging, continuous equal-channel angular pressing and cold drawing. Al–0.97Mg–0.35Zr and Al–1.17Mg–0.34Zr (wt.%) alloys were chosen as objects for investigation to reveal the effect of Mg on the alloys' properties in the processed states. Prior to deformation, the initial rods of the studied alloys were aged at 400 °C for 72 h to attain precipitation of nano-sized particles of the metastable phase Al3Zr (L12) in the aluminum matrix. The following refinement of microstructure in the aged alloys by severe straining followed by cold drawing allows achieving a promising combination of ultimate tensile strength over 320 MPa, plasticity with elongation to failure over 2% and electrical conductivity about 50% IACS. We show that the produced wires exhibit thermal resistance similar to that of the commercial high-strength heat-resistant aluminum alloy (KTAL) type AT2 wire, but with a markedly superior strength. The Mg concentrations and parameters of thermal and mechanical processing that maintain a reasonable trade-off between high strength and acceptable electrical conductivity are discussed on the basis of the presented and earlier reported data to produce high-performance heat-resistant UFG Al–Mg–Zr wires. [ABSTRACT FROM AUTHOR]

A commercial purity of an Al-2mass% Mg alloy (A5052) was processed by severe plastic deformation using high-pressure sliding (HPS) for grain refinement. Mechanical properties and microstructures were examined after the HPS processing and subsequent annealing. Dislocation density decreased and grain growth occurred by the annealing. However, annealing at 150 °C led to an increase in the yield stress σ y to 420 MPa as well as the strain hardening coefficient (n = 0.49) defined in Ludwik's equation in comparison with σ y = 375 MPa and n = 0.25 in the as-HPS-processed state. It was shown that a Hall–Petch relation holds with a coefficient, k = 0.16 MPa m−1/2. The ratio of Vickers harness to tensile stress ( H v / σ TS ) was ~ 3, while the ratio to the yield stress ( H v / σ y ) was 3.3–4.8. Furthermore, plotting of several SPD methods including this study for tensile strength against equivalent strain resulted in a linear relationship and indicated that the HPS process yielded the highest strengthening. The strengthening mechanism was evaluated for the HPS-processed A5052 alloy so that the dominant contribution to the strengthening was from the grain boundary hardening due to significant grain refinement, which was up to 70% of the total strength. [ABSTRACT FROM AUTHOR]

In this paper, the effect of deep cryogenic treatment (DCT) on the microstructure and properties of automotive 6063 aluminum alloy at different times was investigated with automotive 6063 aluminum alloy as the research object. The results show that under the conditions of deep cryogenic treatment, the lattice distortion occurs in the alloy matrix microstructure, and the resulting internal stress promotes the large proliferation of dislocations within the alloy and the increase of dislocation density; meanwhile, after the deep cryogenic treatment, the deformed grains are transformed into recrystallized and sub-crystals structural grains, the grains are refined, and the size of the grains is refined from the original 25.2 μm to 20.3 μm, with fine equiaxed crystals. Among them, the mechanical properties of the DCT36h specimen were the best, and its hardness, tensile strength, yield strength and elongation reached 142.44 HV, 328.32 MPa, 177.42 MPa, and 29.29%, which were 34.17%, 5.62%, 11.10%, and 32.77% higher than the original sample, respectively. We believe that the main mechanism for the increase in toughness is multiple reinforcement such as dislocation strengthening, grain refinement strengthening, precipitated phase strengthening and texture strengthening. [ABSTRACT FROM AUTHOR]

This work focuses on understanding the mechanical behavior of CMT (cold metal transfer)-welded joints in AA6061-T651 aluminum alloy while establishing a correlation with the microstructural features observed in the weld zones. Furthermore, the mathematical framework of a coupled continuum damage mechanics and anisotropic plasticity model under finite strain formulation is presented. The aim is to accurately describe the mechanical behavior, fracture, and damage evolution of CMT-welded joints in AA 6XXX alloys. The calibration of the proposed model is performed using experimental data obtained from uniaxial tensile tests conducted on various weld zones, including the base material, heat-affected zone, and fusion zone. To capture the overall behavior of the welded joint, a composite framework is employed. This framework incorporates multiple in-series elasto-viscoplastic elements, each representing a specific welding zone. Demonstrating robust predictive capabilities, the model successfully predicts critical mechanical properties, including yield stress, ultimate tensile stress, and strain to fracture, for 6061-T651 aluminum alloy CMT welds and their respective weld zones. Notably, the model achieves a high degree of accuracy, with accuracy of approximately 0.8, 0.98, and 0.9, respectively, compared with experimental values. The experimental results and numerical simulations exhibit a close agreement, validating the accuracy and predictive capability of the proposed model. Additionally, the model demonstrates its ability to capture the evolution of damage throughout the loading process. The proposed modeling approach effectively captures the unique characteristics of each welding zone and provides valuable insights into the fracture and damage evolution of the welds. [ABSTRACT FROM AUTHOR]

This study presents a comparative analysis of texture evolution, deformation mechanisms, and dislocation density evolution in pure copper, Al-1100 alloy, and Mg AZ31 alloy subjected to equal-channel angular pressing (ECAP). For that purpose, a unique grain fragmentation model combining continuum dislocation dynamics with Taylor-Lin crystal plasticity is presented. Copper and aluminum alloys, with their face-centered cubic (FCC) crystal structures, exhibit similar micromechanical processes during grain fragmentation. The post-ECAP textures for both materials align with ideal orientations, indicating a rotation of grains around the center of the flow direction. On the other hand, the magnesium AZ31 alloy, with its hexagonal close-packed (HCP) crystal structure, displays a rolling-like texture. Al-1100 showed high dislocation multiplication rate favored by dislocation glide, while Mg AZ31 displayed slower dislocation density evolution at 200 °C which can be associated with dynamic recrystallization and twinning low activity. Indeed, driven by elevated temperatures, dynamic recrystallization could form new grains, resulting in a gradual increase in dislocation density. Furthermore, the comparison of average grain size reduction rates aligns with the dislocation density findings, with aluminum alloys experiencing significant grain fragmentation and Mg AZ31 alloy undergoing the slowest rate of grain fragmentation. The employed continuum dislocation dynamics (CDD) coupled with a crystal plasticity modeling approach enables the prediction of material responses, offering a powerful tool for understanding and optimizing deformation behavior. Further research opportunities lie in exploring additional factors and refining the understanding of deformation behavior in FCC and HCP materials, as well as expanding the applicability of the modeling approach to other materials and processing techniques. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced thermoplastic composites (CFRTPs) are widely used in industrial manufacturing due to their excellent mechanical properties, and the joining of lightweight metal/CFRTP hybrid structure has gained more attention. Ultrasonic welding is a promising method for achieving metal/CFRTP dissimilar joining. In this study, 6061 aluminum alloy and carbon fiber-reinforced polyamide-66 (CF/PA66) were ultrasonically welded by preparing a PA6 coating on the surface of aluminum sheet as an interlayer. This paper investigates the effects of welding parameters on the joint mechanical property. Optimized process parameters (welding force 600 N, amplitude 60% and welding time 0.6 s) are determined by experiments. The effects of the thickness and crystallinity of the PA6 coating on the joint strength are investigated. The results show that there exists an optimal coating thickness that maximizes the joint strength. Low crystallinity of the coating contributes to high joint strength. Mixed failure mode (adhesive failure, substrate failure and cohesive failure) is observed based on the analysis on the fracture surface. [ABSTRACT FROM AUTHOR]

This paper presents experimental ductile fracture data for 2139-T8 aluminum alloy under various stress states for the ultimate purpose of probing the fracture envelope as a function of stress triaxiality and normalized Lode angle. A new ductile fracture model is also proposed and validated by experimental data, along with the evaluation of existing ductile fracture models. The data extracted from published literature on 2024-T351 aluminum alloy was also used as an additional experimental data set for validation. An extensive experimental program was implemented to produce data in a wide range of stress states, including tensile tests (with round smooth, round notched, and plate specimens), torsion, compression (with round smooth and round notched specimens), and shear-compression experiments (two different sizes). The combined effects of stress triaxiality and normalized Lode angle were used to define a 3D fracture envelope for fracture strain. A parallel finite element simulation (fine-tuned by the experimental results) has been performed for each experiment to evaluate the evolution of stress triaxiality and normalized Lode angle in the critical section of the specimens with complex geometries. Finally, these results were used to develop two fracture models whose predictions were compared with some of the existing models. [ABSTRACT FROM AUTHOR]

The traditional design process for aluminium alloys has primarily relied upon iterative alloy production and testing, which can be time intensive and expensive. Machine learning has recently been demonstrated to have promise in predicting alloy properties based on the inputs of alloy composition and alloy processing conditions. In the search for optimal alloy concentrations that meet desired properties, as the search space expands, the optimisation process can become more time intensive and computationally expensive, depending on the methodology used. We propose a faster workflow for inverse alloy design by using multi-target machine-learning models. We train a random forest regressor to predict the concentration of alloying elements and a random forest classifier to determine the processing condition. We further analysed the inverse model and validated findings against alloys reported in the literature. [ABSTRACT FROM AUTHOR]

Electromagnetic treatment (EMT) plays a critical role in the manipulation of microstructures and properties in aluminum alloys. This study aims to investigate the impact of EMT on stress corrosion cracking (SCC) resistance in 7075 aluminum alloy and to reveal the underlying mechanisms from both thermodynamic and kinetic perspectives. The results demonstrate that EMT has a significant positive effect on the stress corrosion resistance of the aluminum alloy. It effectively reduces the elongation loss from 11.2 to 2.6% and the SCC susceptibility index from 3.9 to 1.4%. This improvement can be attributed to two primary mechanisms: (1) the energy supplied by the electromagnetic field lowers the thermodynamic barriers for the dissolution of precipitates, even at temperatures below the critical threshold. This facilitates the dissolution and coarsening of precipitates, ultimately reducing the alloy's susceptibility to stress corrosion in various environments. (2) The activation energy provided by the electron wind force facilitates the movement and annihilation of dislocations, leading to a reduction in residual stresses and further enhancing the aluminum alloy's resistance to stress corrosion. [ABSTRACT FROM AUTHOR]

This paper presents a method for joining Si3N4 and 7A52 aluminum alloy using femtosecond laser surface modification of Si3N4 ceramics. This study investigated the impact of laser scanning speed on the morphology, chemical composition, and wettability of Si3N4 ceramic surfaces, as well as the mechanism behind the laser-assisted joining of Si3N4 and 7A52. After undergoing femtosecond laser processing, the ceramic material underwent modifications resulting in the creation of a periodic groove structure. This structure featured an ideal depth-to-width ratio that effectively increased the surface area for bonding with the solder. Furthermore, the surface of Si3N4 experienced thermal decomposition, which produced a recrystallized layer of 'Si.' This layer improved the solder's wetting effect on the ceramic surface, which led to a stronger diffusion of Al and Mg elements to the ceramic interface. The presence of the periodic groove structure also changed the fracture path of the joint, ultimately enhancing the strength of the brazed joint by approximately 52.4% when compared to the original joint. Notably, this significant improvement was achieved without the need for surface metallization. In summary, the femtosecond laser processing method significantly improved the strength of the ceramic–metal brazed joint through surface modifications, promoting a more reliable and robust bond. [ABSTRACT FROM AUTHOR]

NiTip/1060Al lamellar composites exhibiting low-temperature phase transformation damping characteristics were synthesized through composite rolling technology. This study explores the impact of varying volume ratios of NiTi particles and 1060Al particles in the particle layer and the rolling temperature on the phase transformation characteristics and damping behavior of the composites. The NiTi particle layer in the composites features numerous interparticle interfaces with weak bonding. Notably, the composite displays the phase transition characteristic of NiTi alloy, which is absent in aluminum alloy. In comparison to 1060Al alloy, the failure mode of the interlaminar interface enhances the tensile strength of hot-rolled composites. Furthermore, the damping properties of NiTip/1060Al lamellar composites significantly surpass those of the 1060Al alloy. While the volume ratio of NiTi particles to 1060Al particles in the particle layer and the rolling temperature have minimal effects on the internal friction peak temperature of the composites, an increase in NiTi particle volume content or a decrease in rolling temperature gradually elevates the peak value of phase-transition internal friction. At 62 °C, the internal friction value of the composite with the highest NiTi particle volume content is 435% higher than that of the 1060Al alloy. The internal friction peak temperature of the composites primarily depends on the phase transformation of NiTi particles. During vibration deformation, the micro-slip motion of the weak bonding interface between particles induces the interface damping behavior of the interface, significantly improving the low-temperature damping performance of the composites. [ABSTRACT FROM AUTHOR]

Two A356 aluminum alloys (Al–Si–Mg), one with 0.09 wt.% Fe and one with 0.91 wt.% Fe, were cast in a graphite mold with simultaneous local ultrasonic processing to refine the as-cast microstructure. Ultrasonication during casting transformed the morphology of primary Al grains from dendritic (~ 140–290 microns in size) to globular (~ 33–36 microns in size). The alloy with high Fe exhibited globular grains at distances up to 45 mm away from the ultrasound probe, while the alloy with low Fe exhibited globular grains at distances only up to 6 mm away from the ultrasound probe. Near the location of the ultrasound probe (< 2 mm away), a second non-dendritic microstructural morphology was observed with fine aluminum grains (~ 9–25 microns in size). This unique fine-grained morphology has not been previously reported, contains a greater area fraction of Si relative to the globular microstructure, and may be a large, fully eutectic region. Ultrasonication during casting also transformed the morphology of the β-Al5FeSi phase particles (which are deleterious to the strength and ductility of the alloy) in the high Fe alloy from needle-like to rectangular, which could enable the greater use of secondary Al alloys. Thermodynamic simulations conducted to calculate the solidification paths of the two alloys studied predict that the β-Al5FeSi phase begins to form earlier in the alloy with high Fe. Data suggest that the β-Al5FeSi phase (which is more abundant in alloys with high Fe content) may enhance ultrasonically-induced grain refinement. [ABSTRACT FROM AUTHOR]

Traditional isothermal aging treatments could not balance the relationship between mechanical properties and corrosion resistance of ultra-high-strength Al–Zn–Mg–Cu alloys. Therefore, the effect of non-isothermal aging (NIA) treatments on the microstructure and properties of TiC-TiB2 (BC) ceramic particles-reinforced spray-formed 7055 aluminum alloy tungsten inert gas (TIG) weld metal (WM) has been investigated. Weld joints were solid soluted at 475 °C for 2.5 h and quenched in water at 65 °C. Then, they were heated from 100 to 180 °C firstly at the rates of 60, 40, and 20 °C h−1 and cooled from 180 to 100 °C at the rate of 20 °C h−1. The results show that the mechanical properties of WM improve as the variable temperature rates decrease and its corrosion resistance deteriorates. The tensile strength of BC-20 is the best (580 ± 25 MPa), and the corrosion resistance of BC-60 is the best. The NIA treatments promote the formation of narrower precipitate free zones and finer-dispersed precipitates. Therefore, the mechanical properties (565 ± 25 MPa, 4.20 ± 0.21%) and corrosion resistance of BC-40 are excellent in the shorter aging time. [ABSTRACT FROM AUTHOR]

A recently emerged XRD-based cosα residual stress measurement method, which utilizes imaging plate detectors, has attracted special attention from both academia and industry. There are uncertainties about to which extent the method could be used and about the accuracy of the measurements when analyzing industrial components. This work investigates the accuracy of the method by targeting four common types of material structures for the XRD experiments: preferred orientation of the microstructure (texture effect), coarse grain microstructure (coarse grain effect), a combination of both, and materials with steep lateral or in-depth residual stress gradients. The analysis was carried out by the conventionally used sin2ψ and the newly developed cosα methods on ferritic and austenitic steels, aluminum alloys, and SiSiC ceramics. The results indicate that both methods are reliable in most cases. However, cosα method has higher uncertainties and is more sensitive to the initial microstructure of the material. [ABSTRACT FROM AUTHOR]

This study investigates the influence of hot rolling on the quench sensitivity and heterogeneous precipitation behavior of 7150 aluminum alloy using an end-quenching process combined with conductivity testing, hardness testing, scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy, scanning transmission electron microscopy, and high-resolution transmission electron microscopy. The results reveal that hot rolling significantly increases the quenching sensitivity of the 7150 aluminum alloy, as evidenced by the enhancement in conductivity difference from 0.7 to 1.6% IACS and the rise in hardness drop from 5.5 to 12% at both ends after hot rolling. Microstructural analysis indicates the presence of equiaxed grains with low dislocation density and well-coherent Al3Zr particles in the primitive alloy, with small precipitates of the η phase on the Al3Zr particles. Subsequent to hot rolling, recrystallization occurs, thereby resulting in the generation of numerous high-angle grain boundaries (HAGBs), incoherent Al3Zr particles, dislocations, and coherent Al3Zr particles. Consequently, this leads to increased variety, nucleation sites, sizes, and quantities of heterogeneous precipitates. HAGBs, characterized by high interfacial energy, are found to be the most favorable for the nonuniform nucleation and precipitation of the η phase, followed by low-angle grain boundaries. Significant precipitation of the η and T phases is observed on the noncoherent Al3Zr dispersoids within the recrystallized grains and some subgrains (SGs). Furthermore, the high-dislocation-density SGs not only facilitate the precipitation of the η and T phases but also result in the precipitation of the S and Y phases. [ABSTRACT FROM AUTHOR]

A novel electromagnetic shocking treatment (EST) was put forward to selectively embellish interface microstructure of solid alloy and improve its performance in our previous work. However, considering the nonlinear response characteristic of phase evolution under EST, the effect of precipitates evolution on precipitate and microhardness distribution of Al7075-T73 alloy is worth of attention and still unknown. Herein, microhardness distribution test and TEM characterization of precipitates for Al7075-T73 alloy are carried out to explore the influence mechanism of EST on the precipitate and microhardness distribution. Compared with the received sample, the microhardness distribution turns more homogeneous, while the average microhardness remains basically constant for EST sample. Besides, for EST sample, grain boundary precipitates (GBPs) dissolve and coarsen obviously, while there also exists that the distribution of matrix intragranular precipitates remains basically constant with that of the received sample. Meanwhile, stripy grain boundaries (GBs) can be observed more commonly and GB wetting occurs for EST sample. It indicates that EST promotes nonlinear interface wetting and results in nonlinear phase transition, inducing significant GBPs transformation and then gradient phase transition of precipitates within grain size scale. The resultant gradient phase distribution combined with nonlinear interface bridging promotes a more homogeneous microhardness distribution without losing the mechanical properties of aluminum alloy. This work provides a new understanding about the effect of EST on the microstructure evolution process of solid alloy and is beneficial to the optimization of EST process to improve the service performance of alloys and even finished parts. [ABSTRACT FROM AUTHOR]

Marine biofouling presents a significant challenge to the sustainable development of the maritime industry. Antimicrobial peptide (AMP) offers a promising strategy to combat biofouling. However, the inherent susceptibility of natural AMPs composed of L-amino acids to proteolytic degradation limits their practical application. This study investigated the stability of peptides containing d-amino acids against proteolytic degradation and evaluated their antifouling performance through the modification of aluminum-based surfaces with these peptides. d-peptides exhibited remarkable stability compared to the l-peptides counterpart when exposed to pepsin. Furthermore, the surfaces modified with d-peptides displayed excellent antifouling capacity by significantly inhibiting the adhesion of Bacillus sp. (58.6%) and E. coli (88.7%), the comparable effects observed with l-peptides (61.7%) and (87.5%), respectively. Coarse-grained molecular dynamics simulations and scanning electron microscopy results analyses revealed that immobilized d-peptides effectively disrupted bacterial cell membranes, thereby preventing bacterial adhesion. This research provided a viable approach to enhance the stability of peptides against proteolytic degradation while maintaining outstanding antifouling performance, contributing to the development of effective strategies for antifouling in the maritime industry. [ABSTRACT FROM AUTHOR]

Enhancing the high temperature mechanical properties and the thermal stability of aluminum alloys are in urgent demand for the lightweight application scenarios (such as pistons, fan blades, crankshafts) working at elevated temperatures. The fabrication of aluminum matrix composites is a promising solution. In this work, TiB2 nanoparticles were in-situ introduced to a typical heat resistant Al–Cu–Mg–Fe–Ni (Al2618) alloy matrix and subjected to hot extrusion. Microscopically, the extruded TiB2/Al composite exhibited refined and bimodal sized grain structure, which was stable after long-time thermal exposure associated with TiB2 particle banding along the extrusion direction. The TiB2/Al composite showed an evident improvement in high temperature strength as well as the strength retention after long-time thermal exposure up to 300 °C, compared to the unreinforced alloy. The strengthening effect was remarkable especially at 200 °C with an increase of ~ 20% (60–70 MPa) in tensile strength and strength retention after thermal exposure but without the trade-off of ductility. The effects of TiB2 particles on the temperature-dependent strengthening mechanisms and microstructure evolutions were investigated. This work inspires the design, processing and evaluation of novel high strength and heat resistant particle-reinforced aluminum matrix composites for the potential applications under elevated temperature service conditions. [ABSTRACT FROM AUTHOR]

Aluminum anodes with fine grain have stronger electrochemical activity and higher corrosion resistance, but the microwave-smelted aluminum alloy anode can be prepared with fine grain. In this work, microwave smelting has been used to refine grain size and optimize the precipitated phase in an aluminum alloy anode. The results show that microwave can not only refine the grain and improve the corrosion resistance of aluminum anode, but also the distribution of precipitated phase is more uniform. The fine grain reduces the potential difference inside the aluminum anode, thus activating the electrochemical activity of the anode and improving the corrosion resistance. The corrosion form is also changed from the conventional pit corrosion to uniform corrosion, so as to improve the utilization rate of anode. The capacity density and energy density of 1000 W microwave-smelted aluminum anode were 1554.404 mAh/g and 1955.181 Wh/kg, respectively. Compared with conventional aluminum anode, the energy density and capacity density increased by 92.7% and 64.5%, respectively. Therefore, microwave technology can improve electrochemical performance and battery performance by optimizing microstructure uniformity and refining grain size. [ABSTRACT FROM AUTHOR]

The need for 2219 aluminum alloy and 2195 Al–Li alloy dissimilar friction stir welding (FSW) arises as the conventional 2219Al alloy was gradually replaced by the novel 2195Al alloy in fabrication of fuel tanks. However, the systematic investigation about the effect of welding parameters and material positioning on the microstructure evolution and mechanical properties of dissimilar FSW 2219Al/2195Al joints is lacking. In the present study, 2219Al-T8/2195Al-T8 plates were subjected to FSW under rotation rates of 800–1200 rpm and welding speeds of 200–800 mm min−1 with placing 2219Al-T8 alloys on the advancing side (AS) and retreating side (RS), respectively. The results showed that sound FSW joints were obtained under all the welding conditions. Welding parameters and material positioning affected the joint strength and fracture failure behavior. The FSW thermal cycle resulted in low hardness zones (LHZs) on both the 2219Al-T8 and 2195Al-T8 sides. The LHZ on the 2219Al-T8 side, characterized by partial coarsening of θ′ (Al2Cu) precipitates and dissolution of the residual precipitates, showed the minimum hardness in the entire FSW joints. When 2219Al-T8 alloy was placed on the AS, the LHZ on the 2219Al-T8 side experienced higher peak temperature, and therefore more dissolution of θ′ than that on the RS, thereby obtaining higher tensile strength. The tensile strength of the FSW joints at room temperature and − 196 °C largely increased as the welding speed increased from 200 to 400 mm min−1. The FSW joints presented much higher tensile strength at − 196 °C than that at room temperature under the identical welding parameters and material position. The FSW joints fractured along the LHZ on the 2219Al-T8 side during tension. For the bending testing, the up and down bending failure angles were about 91–117° and 88–109°, respectively, with the weak zone appearing in "S" line or HAZ on the 2195Al-T8 side. [ABSTRACT FROM AUTHOR]

AA6101 Al alloy is widely used as a high-strength conductive aluminum alloy, and the contents and existence of Mg and Si can influence its electrical conductivity and mechanical properties obviously. In this paper, experiments were conducted to find the optimal Mg, Si additions and Mg/Si ratio and then combined with heat treatment to improve the EC and mechanical properties at the same time. Firstly, considering the proper Mg/Si ratio, two optimal Mg and Si additions were determined: Al–0.7Mg–0.5Si and Al–0.4Mg–0.7Si with EC of 51.5%IACS and 51.4%IACS, and through homogenization treatment, their EC improved to 57.0%IACS and 55.7%IACS, respectively. Then, appropriate Fe was added to further control Si to achieve the balance of EC and mechanical properties. Results showed that for AA6101 Al alloy the ideal Mg/Si mass ratio was 1.4 and high Mg and low Si can obtain good EC and mechanical properties. Besides, it can be found that at low Mg/Si ratio, the alloy conductivity takes longer to reach its peak hardness. So the best performance Al–0.7Mg–0.5Si–0.2Fe alloy was obtained within the range of AA6101 national standard. The EC of Al–0.7Mg–0.5Si–0.2Fe can reach 56.3%IACS, and hardness is 91.3 Hv. Based on the study, a schematic diagram was drawn to analyze the influence mechanisms of Mg, Si and Fe on EC and hardness of AA6101 Al alloy. [ABSTRACT FROM AUTHOR]

In this work, micro-arc oxidation was applied to fabricate a high voltage resistance Al2O3-based ceramic coating on the surface of aluminum alloy. The microstructure and insulating properties of the coatings were characterized by XRD, SEM and breakdown voltage testers. The growth behavior and insulation property of the oxide layer in "soft" regime conditions of micro-arc oxidation were determined. The relative contents of α-Al2O3 increased with "soft" plasma discharge time. The soft plasma discharge brought about a tendency of the micro-arc oxide coating to grow outward, further repairing the coating defects and yielding a denser coating layer with improved corrosion protection. Due to the presence of negative currents, the thickness of the whole layer increased, while the inner layer became denser and thicker as a consequence of soft sparks, favoring an increase in the density of the bulk coating layer. The breakdown voltage reached values above 1000 V after 20 min of soft plasma discharge, improving the of micro-arc oxidation coating insulation properties. The oxide layer is thus proposed as a potential candidate for insulation shielding of etching equipment. [ABSTRACT FROM AUTHOR]

Macrostructure, microstructure, and distribution of phases through the interface were analyzed for friction-stir-welded joints 5083 aluminum alloy and 316L steel. Several analytical techniques, including light microscopy, transmission and scanning electron microscopy, elemental analysis using X-ray spectroscopy, and electron diffraction, were used to thoroughly analyze the weld interface. The interface is characterized by a significant reduction in grain size for both aluminum alloy and stainless steel. New compounds, not corresponding to thermodynamically stable phases in the binary Al–Fe phase diagram, were found in the stirred zone (SZ) as dispersed particles. On the steel side of the welding, thin slabs of new compounds were found, as well, being interlaced with the stainless steel. The observations support that the grain refinement of stainless steel is likely due to a continuous dynamic recrystallization. The intermetallic compounds present as a layer at the interface, exhibiting nanometric grain size, were identified by electron diffraction as Al13Fe4 and Al5Fe2 phases. Concerning the intermetallic compound formed in SZ, the elemental analysis showed a compound containing principally Al and Fe, with admixture of Si and Mn. It was concluded that it is a pseudo-ternary compound with body-centered cubic structure, Im-3 space group, which is for the first time reported in this kind of dissimilar assembly, and is known as α-Al(Fe,Mn)Si. [ABSTRACT FROM AUTHOR]

The August 2024 issue of the Journal of Materials Science features a cover paper titled "Stabilized CsPbBr3 quantum dots in flower-like LYH matrix for high-performance white light-emitting diodes" by Yanrui Yang and colleagues at Fuyang Normal University in China. The paper explores the production and properties of these materials, with a focus on their luminescence data. The paper is part of the "Chemical routes to materials" Topical Collection, but could also be relevant to the "Electronic materials" Topical Collection. The article is freely accessible online through the SharedIt link provided. The publisher, Springer Nature, maintains a neutral stance on jurisdictional claims and institutional affiliations. [Extracted from the article]

The June 2024 cover image of the Journal of Materials Science features a paper by Liss et al. titled "Recrystallization of bulk nanostructured magnesium alloy AZ31 after severe plastic deformation: an in situ diffraction study." The image is an artistic representation of nanostructured magnesium alloy AZ31 undergoing heating, showcasing the process of recrystallization in reciprocal space. The paper is part of a Special Issue on "Processing Bulk Nanostructured Materials," which includes a total of 28 articles covering various aspects of severe plastic deformation (SPD) in the processing of bulk nanostructured materials. The Special Issue aims to highlight the enduring significance and resilience of research in this field. Both the paper and the preface of the Special Issue have SharedIt links for easy sharing with readers. [Extracted from the article]

The microstructure and elemental composition evolution of Cf/SiC–Al composites prepared by combined precursor infiltration pyrolysis (PIP) and vacuum-pressure infiltration processes after high-temperature oxidation for different times was investigated. Meanwhile, the mechanical properties of the composites after oxidation treatment were characterized by nanoindentation and compressive performance tests. The results show that when the oxidation temperature was 400 °C and above, the weight loss rate of the composites gradually increased with the prolongation of the oxidation time, and the interface separation between the carbon fiber and SiC matrix became more obvious. Moreover, the nanoindentation elastic modulus of the Al alloy matrix and the SiC matrix decreased significantly with the increase in oxidation time, while the nanoindentation hardness of the aluminum alloy hardly changed. After oxidizing at 400 °C for 7 h, the in-plane compressive strength of the composites reached the maximum (584.7 MPa), and after oxidizing at 500 °C for 9 h, the compressive strength decreased to the minimum (347.8 MPa). [ABSTRACT FROM AUTHOR]

Cold rolling the CC AA 5754 aluminum alloy to different reductions was followed by an hour of annealing at 537 °C under varied pressures. The changes in microstructure and texture were studied. According to the findings, high-pressure heat treatment restricts recrystallization, and the restriction effect is stronger as pressure rises. The refining impact of high-pressure heat treatment can refine recrystallized grains, and it becomes stronger as the rolling reduction gets higher. The variation of recrystallization texture is significantly affected by high-pressure heat treatment. The sheet with a 19.6% reduction is found to have a weak cube texture at atmospheric pressure and 2 GPa, but the sheet that has been annealed at 4 GPa and 6 GPa has a strong cube texture and a weak β fiber rolling texture. High-pressure heat treatment improves the intensities of the cube and R textures in the fully recrystallized sheets with the same reduction. The strengthening impact of R texture from high-pressure heat treatment improves with increasing rolling reduction. [ABSTRACT FROM AUTHOR]

Friction stir spot welding on Al 6061-T6 aluminium alloy was performed to examine the influence of parameters, e.g. tool pin profile, shoulder plunge depth, diameter of shoulder and SiC particles on mechanical properties, macro-structural and micro-structural properties of welds. During the detailed experimentation the behaviour of hook formation, stir zone width, bonded region width and tensile-shear strength was scientifically measured, studied and discussed. Distribution of SiC particles was analysed as it affected the weld quality. Homogeneous distribution of SiC particles helped in entrapping the dislocations during tensile-shear loading of welds. A stronger weld was witnessed with the increase in diameter of the tool shoulder, while there was an increase and then a sudden decrease in weld strength with increase in shoulder plunge depth. Square tool pin was identified as optimum tool pin profile for obtaining stronger welds. The reduction in hook formation was observed with increased shoulder diameter and shoulder plunge depth. Square tool pin increased the material flow and reduced hook length by pushing it away from key hole due to increased stir zone width. SiC particles were observed to be homogeneously distributed with square tool pin profile, greater diameter of tool shoulder and optimum shoulder plunge depth. [ABSTRACT FROM AUTHOR]

A change in the heat treatment state of aluminum matrix before anodization was used to change the state of Mg in this work. The effects of Mg on the interface structure of the film/substrate of anodized AA6082 alloys were systematically studied when Mg existed in the state of Mg5Si6, supersaturated solid solution, and atomic clusters or GP zones. The cross-sectional morphology and film/aluminum alloy interface structure of the oxide film were characterized by SEM and HRTEM, respectively, and the reciprocating friction test was used to compare and analyze the effect of different film/aluminum alloy interface structures on the friction resistance of the oxide film. The results show that the state of Mg before anodization plays a key role in the stability of the film/aluminum alloy interface after anodization, which also has an important impact on the wear performance. Before anodization, the anodized AA6082 alloys have the best friction resistance when the Mg exists in atomic clusters or GP zones, follow by the supersaturated solid solution, and the last is the β″ phase. [ABSTRACT FROM AUTHOR]