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Mg-2.2Gd-0.4Zr sheets were prepared using transverse gradient extrusion (TGE) technology to improve their formability. The effects of different TGE processes (inclination angles of the die are 15°, 30°, 37°, 45° and 49°) on the microstructure, texture, mechanical properties, and formability of extruded sheets were researched. Furthermore, the flow behaviors of Mg-2.2Gd-0.4Zr sheets during extrusion were analyzed by the finite element simulation method. For comparison, Mg-2.2Gd-0.4Zr sheets were processed by conventional extrusion (CE) process. Results showed that the texture of TGE sheets was effectively altered. With the increase of the TGE dies tilt angle, the deviation of the basal pole in the center region of the extruded sheet towards the extrusion direction (ED) increased, while in the 1/4 edge region the basal pole deviated towards the transverse direction (TD) along the ED. The multi-type textures formed in TGE sheets are mainly attributed to the extra flow velocity along the TD and the flow gradient along the ED during extrusion. High elongation of 45.6% and low yield stress of 98.9 MPa are obtained for TGE-45 sheets. In addition, the Erichsen value (IE) of the TGE-45 sheet is 5.46 mm, which is about 47% higher than the 3.72 mm of the CE Mg-2.2Gd-0.4Zr sheet. The improved formability is due to the effective coordination of multi-directional strains during the Erichsen test for the TGE sheets.

Magnesium (Mg) matrix composites (Mg-MMCs) with high strength and ductility properties are crucial for the development of lightweight automobiles. In this study, a novel method is proposed for fabricating Mg-MMCs by incorporating nanocopper (Cu) decorated titanium (Ti) particles (Cu@Ti) to reinforce AZ91 alloys. The in-situ generation of the AlCuMg phase at the interface between the Ti particles and the Mg matrix enhances interface integration and promotes the formation of massive twins. The 5.0 wt% Cu@Ti/AZ91 composite exhibits notable mechanical properties, with a yield strength of 238 MPa, ultimate tensile strength of 368 MPa, elongation of 12%, and modulus of elasticity of 46 GPa. These values represent increases of 8.9%, 5.3%, 50.0%, and 2.0%, respectively, compared to those of AZ91 alloys. The strengthening mechanism is mainly attributed to grain refinement strengthening, thermal expansion coefficient mismatch strengthening, Orowan strengthening, and load transfer strengthening. The plasticity improvement benefits from the optimization of the interface structure, grain refinement and twin formation.

In this study, nano Ti/AZ31 composites were successfully prepared by powder metallurgy method, and the strength and plasticity of the composites were improved in both directions. The SEM shows that the Ti particles were evenly distributed at the grain boundary in the sintered composite, and the Ti particles pin the grain boundary to make the grain of the composite significantly refined. EBSD shows that the addition of nano Ti particles significantly reduces the texture strength of the composite and increases the starting probability of the slip system. TEM shows that nano Ti and AZ31 matrix formed stable Al3Ti and MgO phases at the interface, and shows a strong coherent relationship. The nanoindentation test shows that the Ti/AZ31 interface of the composite was stable, the interface bonding energy and interface fracture toughness were gradiently distributed, and the bonding energy and fracture toughness of the interface bonding area were better than those of the matrix. Tensile test shows that the 1.5 wt%Ti/AZ31 composite obtained the best comprehensive mechanical properties with yield strength, ultimate tensile strength and elongation of 143 MPa, 243 MPa and 11.5%, respectively, obviously higher than those of AZ31 alloys. The increased strength was mainly due to the grain refinement and strengthening at grain boundaries. The improved ductility was the result of weakened texture, increase of slip system start-up probability and strong interfacial bonding between Ti particles and AZ31 matrix.

The preparation of Al/Mg/Al laminated metal composites (LMCs) by lamination technique can well combine the good corrosion resistance of Al alloy and the lightweight characteristics of Mg alloy. In this paper, the atmospheric corrosion behavior and underlying mechanism of 6082/AZ31/6082 LMCs with and without side exposure for one year of filed exposure to the tropical marine atmospheric environment were investigated. The results showed that the corrosion rates of AZ31 and 6082 and LMC-C were 55.967, 1.167, and 0.925 g m−2·a−1, respectively. The microstructure of the Al layer on the surface of LMCs underwent a significant transformation, characterized by a noticeable grain refinement and a concomitant increase in dislocation density. Moreover, the potential disparity between the second phase (AlMnFeSi and Mg2Si) and the matrix was diminished. These findings collectively contribute to the enhanced resistance of 6082/AZ31/6082 LMCs to intergranular corrosion and pitting corrosion. However, the accelerated dissolution of the intermediate Mg layer, facilitated by the galvanic corrosion effect during field exposure of the LMCs, resulted in a 4.5-fold increase in corrosion-induced mass loss. Notably, the ultimate tensile strength of the LMCs exhibited insensitivity to field exposure duration, while their plasticity underwent a gradual decline. This comprehensive study elucidates the corrosion behavior and underlying mechanisms of 6082/AZ31/6082 LMCs subjected to a tropical marine atmospheric environment, providing valuable insights for the rational design and development of LMCs with enhanced comprehensive performance.

A novel magnesium-based multi-principal element alloy with the chemical formula Mg54Al22Li11Zn11Ti2 was prepared using the vacuum induction melting method and subsequently extruded at 350 °C. The phase composition of the alloy in its as-cast state and the microstructural changes after extrusion were investigated using various analytical techniques, including SEM, EBSD, EPMA, and TEM. The presented outcomes showed that the as-cast alloy exhibited lattice distortion and fine grain with segregation, while the average grain size decreased significantly and the second phase became more dispersed after extrusion. The mechanical properties of both the as-cast and extruded alloys, including microhardness, tensile strength, compressive strength, and wear characteristics, were evaluated. The extruded alloy demonstrated significant improvements in mechanical properties compared to the as-cast alloy, with a compressive strength of up to 460 MPa, which can be attributed to both fine grain and precipitation strengthening. Both the as-cast and extruded alloys exhibited high hardness due to the accumulation of local dislocations caused by the interlaced precipitation of sub-grains during the super-solid solution state in the as-cast condition. The hardness enhancement in the extruded state resulted from grain refinement induced by DRX. Furthermore, wear tests revealed that the extruded alloy, characterized by smaller second phase sizes, exhibited excellent wear resistance, with wear failure occurring in the form of abrasive and oxidative wear in both the cast and extruded alloys.

In this study, four high-chromium wear-resistant steels with varying vanadium contents were prepared. Their mechanical properties, corrosion behaviour and impact–abrasion–corrosion behaviour were comprehensively investigated in a simulated corrosive slurry environment. The result indicated the effectiveness of vanadium in enhancing the impact toughness of the steel. Notably, high-chromium steel with 0.2% vanadium exhibited notable characteristics, including a Rockwell hardness of 56.2 HRC and an impact toughness of 113.5 J. Introducing vanadium enhanced the corrosion resistance of high-chromium steels in electrochemical experiments. In terms of impact–abrasion–corrosion performance, the high-chromium steel containing 0.2% vanadium exhibited the highest resistance to impact–abrasion–corrosion when subjected to both the impact energies of 3 J and 6 J. Comprehensive examinations of surface and cross-sectional damage, coupled with detailed microstructure and microhardness analyses, revealed that the development of a white etching layer on the material's surface is crucial to enhancing its resistance to impact–abrasion–corrosion.

The necessity for high performance and low-cost materials caused the researchers worldwide to switch the focus from traditional steel materials to new particle-reinforced steel matrix composites (PR-SMCs). In the recent pasts, a significant effort has been made in this direction to fabricate numerous types of PR-SMCs. Especially, PR-SMCs have attracted much attention in the field of wear resistance due to their excellent overall performance. However, the PR-SMCs preparation process and the choice of reinforcement particles can vary considerably depending on the performance requirements under different conditions of use. This review article aims to explore the recent advancements in the preparation of PR-SMCs. The advantages and disadvantages of the composites under different preparation processes are analyzed and summarized in detail. The future scope of the PR-SMCs is also briefly discussed at the end of the manuscript.

To control the microstructure and improve the mechanical properties of Mn–Cu alloy additive manufacturing components, this work adopts various scanning strategies (rotations of 0°, 45°, 67°, and 90° between successive layers) to change the heat input distribution and heat dissipation. The results show that the scanning strategies can impact the porosity, cracks, grain size, and grain growth direction of Mn–Cu alloy additive manufacturing parts. By adjusting scanning strategies to change the heat flow direction the columnar-to-equiaxed transition can be achieved. The samples exhibit minimal cracks and pores (porosity of 0.0006 %). Using a scanning rotation angle of 67° during processing, the maximum tensile strength can reach 510 MPa with a 29 % elongation, attributed to effective grain refinement and a high dislocation density. This study demonstrates the feasibility of grain refinement and improved mechanical properties for the Mn–Cu alloys by changing the scanning strategies.

Transverse gradient extrusion (TGE) processes with different die inclined angles of 15°, 30°, 45°and 60° were used to produce Mg–3Al–1Zn sheets, thereby tailoring texture and mechanical properties of Mg alloy sheets. Microstructure, deformation texture and final mechanical properties of the obtained sheets were detected and discussed. Furthermore, the rheological behavior of Mg alloys during extrusion was analyzed by finite element method. As the TGE die inclined angle changed, the flow velocity along the transverse direction (TD) and effective strain difference along extrusion direction (ED) were changed during extrusion, and therefore the microstructure and texture of extruded sheets are altered. With increase of TGE die inclined angles, fine grain size and uniform microstructure were obtained. The base poles of most grains for the extruded sheets gradually deviate from normal direction (ND) to ED at center region and inclined from ED to TD at 1/4 edge region. A large elongation of 33.9 % and a low yield stress of 125 MPa can be obtained in the TGE-45 sheet.

It is a great challenge to simultaneously improve the strength and ductility of magnesium matrix composites (MMCs). In this work, AZ91 alloys reinforced with 1 wt%, 2 wt%, and 3 wt% Ti particles were produced using stir casting combined with ball milling process. The microstructure of the extruded composite sheets was analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), electron backscatter diffraction (EBSD). Transmission electron microscopy (TEM) was utilized to observe the structure of the Ti/Mg interface. The mechanical properties of the composite sheets were also investigated. The results show that the adding Ti particles, the texture strength decreased, and the growth of recrystallization grains was also restrained. Due to the interfacial reaction between Ti and Al, the formation of β-phase (Mg17Al12) was inhibited. The tensile test demonstrated that the Ti particles could significantly improve the mechanical properties of the AZ91 alloy sheets. Compared to AZ91 sheet, 2Ti/AZ91 composite sheet along extrusion direction (ED) showed the best comprehensive mechanical properties. The improvement in mechanical properties was mainly attributed to grain refinement, texture weakening, mismatched coefficient of thermal expansion (CTE), and work hardening.

This study aims to synthesize composite materials using TC4 particles and AZ91D alloy through semi-solid stirring and hot extrusion techniques. The main objective is to investigate the microstructure, mechanical properties, wear resistance, and corrosion behavior of composites comprising a minor volume fraction (0, 2, and 5 vol%) of spherical TC4 particles. The findings showed that the dual synergistic effect of TC4 particles and the β-phase leads to a refinement in the grain size of the composite material. Moreover, the incorporation of TC4 particles enhances the hardness, yield strength (YS), and ultimate tensile strength (UTS) of the magnesium matrix, with almost no reduction observed in ductility. Additionally, the TC4/AZ91D composite displays lower wear rates and friction coefficients compared to the matrix when subjected to forces of 150 N and 300 N. However, the corrosion performance of the composite material deteriorates due to the influence of the galvanic effect between the particles and the matrix.

Magnesium (Mg) based composites are often difficult to achieve the trade-off between strength and ductility. The titanium (Ti) metal particles, which show better wettability and ductility than ceramic particles, are selected as reinforcements to simultaneously enhance the strength and plasticity of Mg alloys. In this work, the TC4 (Ti-6Al-4V) particles (2, 4 and 6 vol %) reinforced AZ91 composites were successfully fabricated by the mechanical and ultrasound-assisted stirring method. By incorporating 4 vol% TC4 particles, the composite reached the optimum yield stress, ultimate tensile stress, and elongation of 257 MPa, 370 MPa and 18.7%, respectively. The microstructural characterizations revealed that the fine and coarse grains were observed in the AZ91 and TC4/AZ91 composites. The dynamic recrystallization behavior was retarded in the TC4/AZ91 composites, which was rooted in the TC4 particles and fine Mg17Al12 phase. Transmission electron microscopy (TEM) showed that the interfacial product at TC4/Mg interface was Al3Ti phase. Based on the quantitative calculations, the strengthening effects of the 4TC4/AZ91 composite were mainly the coefficient of thermal expansion strengthening, grain refinement strengthening and the deformable TC4 particles.

In this study, a composite steel plate for marine construction was fabricated using 316L stainless steel and A6 carbon steel through hot rolling. Neutral salt spray tests and electrochemical experiments were performed to analyse the corrosion behaviours of the cladding material, the carbon steel substrate, and the interface between stainless steel and carbon steel in a marine atmosphere and seawater. The results showed that an evident elemental overlap region was observed at the composite interface of the composite steel plate. After long salt spray test, the A6 carbon steel part showed significant accelerated corrosion along the interface, resulting in the interface specimens corroding at a faster rate than the carbon steel substrate. However, the composite interface showed better corrosion resistance than the carbon steel substrate in the electrochemical tests. A corrosion resistant layer with a width of 15 μm was found on the stainless-steel side of the composite interface.

For magnesium matrix composites (MMCs), it is crucial to enhance their strength while maintaining plasticity. In this work, Ti particle (TiP) reinforced VW94 composites (TiP/VW94 composites) with varying amounts of Ti particles were prepared using a semi-solid stirring-assisted ultrasonic vibration method followed by homogenizing treatment. Microstructural analysis revealed that the addition of Ti particles resulted in grain refinement and facilitated the formation of lamellar long period stacking ordered structure (LPSO) during homogenizing treatment due to the increasing dislocation density. In addition, the jagged interfacial product of MnTi phase was generated at the interface between Ti particles and Mg matrix, and a strong interfacial bonding was formed at the Mg/Ti interface. The tensile test results show that the strength and elongation of TiP/VW94 composites all improved than VW94 matrix alloy and the 5%TiP/VW94 composite presents the best tensile properties with yield strength (YS), ultimate tensile strength (UTS), and elongation of 173 MPa, 256 MPa and 5.9%, respectively. The improved tensile properties of TiP/VW94 composites can be attributed to grain refinement, load transfer, dispersion strengthening, dislocation strengthening, and an increase in lamellar LPSO.

Generally, edge crack of rolled magnesium alloy sheets initiates in the RD (rolling direction)-ND (normal direction) plane and then propagate in the RD-TD (transverse direction) plane. Hence, the Mg-2Zn-1.5Mn (ZM21) alloy sheets with and without crack notch were designed to carry out in-situ tensile experiments under 150 °C (the same temperature of rolling), with the aim to understand their crack propagation mechanism. The scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) techniques were utilized to reveal microstructural evolution in real time at designated displacements. The results show that the prismatic slip, basal slip, and extension twining play synergistic role in coordinating strain during the tensile process in ZM21 alloy sheet at 150 °C. In both tensile samples with and without crack notch, localized strain is mainly concentrated at relatively fine grain area and the grain boundaries or triple junctions of the grains with large basal Schmid factor (SF) difference, which eventually leads to severe surface roughening and subsequent crack initiation. Compared with the sample without crack notch, the pre-cracked sample exhibits severer deformation at the crack tip due to strain concentration. Strain gradient distribution is observed at the crack tip region in the pre-cracked sample. The crack propagation path of the sample with pre-crack is identified and the underlying mechanism is also discussed.

In this work, the 3D-SiCp/A356 composites with interpenetrating microstructure were prepared by pressure infiltration of A356 aluminum alloy into a porous 3D-SiC ceramic preform, which served as reinforcement. The effects of the surface oxidation treatment of the SiC particles on microstructure, thermal expansion coefficient, and bending strength of as-fabricated composites were investigated. The results revealed that the initial structure of the 3D-SiC ceramic preform could be retained after pressure infiltration, the pores of the preform were filled with A356 aluminum alloy, and the particles were uniformly distributed in the A356 matrix alloy. The thermal expansion coefficient of the SiC/A356 composite reinforced by oxidized SiC particles was lower than that of the unoxidized SiC particle-reinforced composite. It increased with increasing temperature for both, eventually reaching maxima at 420 °C and 350 °C, respectively, and decreased thereafter. However, a rapid decrease in the thermal expansion coefficient was evident at 565 °C because of the over-burning of the A356 aluminum matrix. In particular, the surface oxidation treatment of SiC particles changed the nature of bonding between SiC and Al, which reduced the strength of the composites. As a result, the bending strength of the unoxidized SiC particle-reinforced composite was approximately twice that of the oxidized SiC particle-reinforced composite. Additionally, the bending strength values of the SiC–Al showed an obvious anisotropic behavior. The bending strength measured by loading parallel to the infiltration direction was 2.5 times larger than that of a perpendicular loading.

Titanium (Ti) particles reinforced AZ91 matrix composite (Tip/AZ91) was prepared by powder metallurgy method. In the present work, we investigated the hot deformation behavior of Tip/AZ91 composite by isothermal compression tests at a range of temperature from 250 °C to 400 °C and strain rates from 0.001 s−1 to 1 s−1. Microstructure observations revealed that Ti particles were distributed uniformly in the composite, with the presence of a diffusion layer containing Mg, Ti, and Al elements between the Ti particles and the magnesium (Mg) matrix. The strain-compensated Arrhenius constitutive model was constructed, and the accuracy was evaluated by error analysis. The stress index exponent (n) was calculated as 4.98, indicating that the dislocation climb mechanism dominates the thermal deformation of Tip/AZ91 composite. Moreover, the calculated activation energy (Q) of 153.7 kJ/mol was observed to be lower than that of the pure AZ91 alloy, which can be attributed to the presence of a particle deformation zone (PDZ). Further microstructure analysis indicated that the continuous dynamic recrystallization mechanism (CDRX) occurred. As the recrystallized grains grow, the texture changes from a bimodal texture to a typical unimodal texture, resulting in a recrystallized //normal direction texture. In addition, the particle stimulated nucleation (PSN) phenomenon was observed around Ti particles at low Zener-Hollomon parameter (lnZ = 20.73) condition.

The knowledge graph embedding model aims to use low-dimensional real-valued vectors to represent the entities and relations in the triples, where operations such as link prediction and triple classification can be performed based on these representations. However, existing embedding models only consider the structural embedding of triples, while ignoring the semantic information of triples. This paper proposes a knowledge graph embedding learning framework combined with triple semantic information (KGSE). KGSE comprehensively considers the structural embedding and semantic embedding of triples, where semantic embedding is used as a supplement to improve the quality of embedding. Specifically, KGSE uses the improved TransD model to obtain the structural embedding of triples, and employs the deep convolutional neural model combined with an attention mechanism to obtain the semantic embedding of triples. In addition, a novel energy function is designed to jointly train the above two embeddings. Experimental results show that the proposed framework improves significantly compared with Trans-based models and other baseline models in link prediction and triple classification tasks, which verifies the effectiveness of the proposed framework.

Ti particles (5 wt%) reinforced AZ91 Mg matrix composites (TiP/AZ91 composites) were prepared by powder metallurgy. As a result, the strength and ductility of TiP/AZ91 composites were improved compared with AZ91 alloy. The ultimate tensile stress (UTS) increased significantly from 163 MPa to 221 MPa, and the elongation increased from 3.5% to 10.9%. The YS and hardness decreased due to the slightly coarser grain size. The microstructural results showed that Ti particles were uniformly dispersed in the Mg matrix and the content of Mg17Al12 was reduced, indicating that Ti particles can inhibit the precipitation of the second phase. The interface between Ti particle and Mg matrix showed that the Al3Ti layer was formed at the edge of the Ti particles. EBSD was used to analyze the twins and dislocations at different tensile strains. During the tensile deformation at room temperature, many tensile twins and dislocations formed in the TiP/AZ91 composites. The tensile twins and dislocations could coordinate plastic deformation, thus improving the elongation of the TiP/AZ91 composites.

The recrystallization behavior of extruded Mg–Zn–Mn alloys was systematically investigated under different aging treatment prior to extrusion. Electron backscattered diffraction analysis was used to explore the recrystallization mechanism and corresponding effects on the basal texture of alloys during extrusion. The results show that the primary coarse particles can effectively promote recrystallization nucleation. Moreover, the precipitation of nanoscale particles during the aging process play a role in pinning the grain boundaries. Therefore, after peak-aged treatment (16 h), the extruded Mg alloy obtains uniform and fine microstructure, showing good mechanical properties: the tensile yield strength, tensile strength, elongation, compressive yield strength, and tension-compression yield asymmetry were 298 MPa, 363 MPa, 26%, 260 MPa, and 0.87, respectively.

Currently, many gratifying signs of progress have been made in magnesium (Mg) matrix composites (MMCs) by virtue of their high mechanical properties both at room and elevated temperatures. Although the commonly used reinforcements in MMCs are ceramic particles, they often provide improved yield and ultimate stresses by a significant loss in ductility. Therefore, hard metallic phases were introduced as alternative candidates for the manufacturing of MMCs, especially titanium (Ti). It has a high melting point, high Young's modulus, high plasticity, low level of mutual solubility with Mg matrix, and closer thermal expansion coefficient to that of Mg metal than that of ceramic particles. It is highly preferable to provide both high ultimate stress and ductility in Mg matrix. However, many critical challenges for the fabrication of Ti-reinforced MMCs remain, such as Ti's homogeneity, low recovery rate, and the optimization of interfacial bonding strength between Mg and Ti, etc. Meanwhile, different fabrication methods have various effects on the microstructures, mechanical properties, and the interfacial strength of Ti-reinforced MMCs. Hence, this review placed emphasis on the microstructural characteristics and mechanical properties of Ti-reinforced MMCs fabricated by different techniques. The influencing factors that govern the strengthening mechanisms were systematically compared and discussed. Future research trends, key issues, and prospects were also proposed to develop Ti-reinforced MMCs.

In Mg matrix composites, the interface between Ti2AlC and Mg plays a vital role in the strengthening mechanism and fracture process. Using first-principles calculations, a systematic analysis is carried out for the atomic structures, work of adhesion, interfacial energy, chemical bonding of the Mg(0001)/Ti2AlC(0001) coherent interface. The results of the relaxed interface structure show that, for all the interface studied, the bridge site (MT) configurations are unstable and convert into the hollow site (HCP1 or HCP2) configurations. Moreover, the work of adhesion and interfacial energy measurements reveal that C-HCP2 configurations are more thermodynamically stable. Furthermore, due to the formation of a strong Mg–C covalent bond across the interface, the electronic structure studies indicate that the C-terminated Mg(0001)/Ti2AlC(0001) interface is more thermodynamically stable. The Al-, Ti(C)-, and Ti(Al)-terminated interfacial fractures are found to initiate at the Mg/Ti2AlC interface, whereas the C-terminated interfacial fracture could initiate in the Mg bulk phase.

The compromise between strength and plasticity has greatly limited the potential application of particles reinforced magnesium matrix composites (MMCs). In this work, the Ti particles reinforced AZ31 magnesium (Mg) matrix composites achieved simultaneous improvement in strength, elongation and wear resistance. The Ti particles reinforced AZ31 composites were fabricated by ultrasonic-assisted stir casting with hot extrusion. The results showed that a strong interfacial bonding was obtained at Ti/Mg interface because of the formation of semi-coherent orientation relationship of TiAl/Mg, TiAl/Al2Ti and Al2Ti/Mg interfaces. The as-extruded 6 wt.%Ti/AZ31 composite presented the best compressive mechanical properties and wear resistance with ultimate tensile strength, elongation and wear rate of 327 MPa, 20.4% and 9.026 × 10−3 mm3/m, obviously higher than those of AZ31 alloys. The enhanced mechanical properties were attributed to the grain refinement and strong interfacial bonding. The improved wear resistance was closely related to the increased hardness of composites and the formation of protective oxidation films.

Laminated metal composites (LMCs) are a unique composite material and have great application prospects in automobiles, ships, aircraft, and other manufacturing industries. As lightweight materials, the Mg/Al LMCs are expected to combine the advantages of both Mg and Al alloys to broaden their application prospects. Roll-bonding is the most popular process for the fabrication of Mg/Al LMCs due to high production efficiency and good product quality stability. The roll-bonding process involves the deformation of the substrates and the formation of the interfacial diffusion layer. The latter will directly determine the interface bonding strength of Mg/Al LMCs. Bonding strength is very sensitive to the thickness of the reaction layer in the diffusion layer. When the thickness of the reaction layer exceeds 5 µm, the bonding strength decreases sharply. Therefore, controlling the thickness of the reaction layer is very important for the design of rolling parameters. The latest research also showed that the addition of intermediate layer metal and the construction of three-dimensional interfaces can further improve the interface bonding strength. How to apply these methods to roll-bonding is the focus of future research. Recently, a new rolling technique, corrugated roll/plat roll rolling+flat roll/flat roll rolling has been developed to fabricate Mg/Al LMCs. It can effectively promote the deformation of the hard layer and generate a wavy interface, resulting in the enhancement of the bonding quality and rolling quality. In the current review, the effects of rolling parameters and subsequent annealing on the interface structure of Mg/Al LMCs were elaborated in detail. The application of some special rolling techniques in the preparation of Mg/Al LMCs was also summarized. The latest research results on the relationship between interface structure and mechanical properties of Mg/Al LMCs were reviewed. Finally, further research directions in this field were proposed.

In this study, the coupled ordinary differential equations for the galloping of the first two modes in iced bundled conductors, including in-plane, out-of-plane, and torsional directions, are derived. Furthermore, through numerical analysis, the critical conditions of this modal galloping are determined in the range of wind speed–sag parameters, and the galloping patterns and variation laws in different parameter spaces are analyzed. The parameter space is then divided into five regions according to the different galloping modes. Under the multimodal coupling mechanism of galloping, the impact of single and two kinds of coupled mode galloping on the spatial nonlinear behavior is explored. The results reveal that the system exhibits an elliptical orbit motion during single mode galloping, while an “8” motion pattern emerges during coupled mode galloping. Moreover, two patterns of “8” motion are displayed under different parameter spaces. This research provides a theoretical foundation for the design of transmission lines.

In magnesium–rare earth–transition metal (Mg-RE-TM) alloys, the γ” phase (with a hexagonal structure with the space group P6¯2m) is a critical strengthening phase that can significantly improve their mechanical properties. However, compared to other phases in Mg-RE-TM alloys, research on the γ” phase is less documented, and an understanding of the γ” phase is not well established. As a result, different models of the structure of the γ” phase have been proposed. In this review, we summarize these structural models and find that the γ” phase is different from the Guinier–Preston (G.P.) zone, as revealed via Cs-corrected high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) and density functional theory (DFT) calculations. In addition, we briefly summarize the stability of the γ” phase and its effect on the mechanical properties of Mg-RE-TM alloys.

Low-alloying and low-cost magnesium alloy sheets have the potential for large-scale application. Therefore, the edge cracking developed during the rolling is of great importance. In this work, Mg-1.0Mn-0.5Al (MA10), Mg–2Zn-1.5Mn (ZM21), and Mg-3.0Al-1.0Zn (AZ31) alloy sheets were rolled at 150 °C in different single-pass reductions using online heating rolling. Their edge cracking behaviors at the edge of rolled sheets after large strain rolling were investigated and compared through the scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and digital image correlation (DIC) technique. The results show that compared with ZM21 and AZ31 rolled sheets, MA10 rolled sheets exhibit the most severe edge cracking behavior after large strain rolling. This is mainly attributed to the lower recrystallization degree and ultimate compressive strength, as well as higher strain localization during the plastic deformation. Meanwhile, both coarser second phase particles at the edge and larger grain size difference also promote the initiation and propagation of edge crack in MA10 alloy rolled sheets. In addition, the small crack is developed in front of the crack tip in all of Mg alloys rolled sheets after a single-pass reduction of 75% due to the stress concentration at triple junctions caused by large rolling reduction and maximum shear stress along the plane collinear with the major crack.

Hot compression tests are carried out for the 2219 Al alloys, which are prepared by conventional direct chill casting and internal electromagnetic stirring direct chill casting respectively. The processing maps are constructed and the as-deformed microstructures are observed to investigate the effects of internal electromagnetic stirring on the hot deformation of 2219 Al alloy. The results show that the internal electromagnetic stirring expends of stability domain, especially increasing the corresponding range of strain temperature. The suitable deformation parameters of internal electromagnetic stirring direct chill casting 2219 Al alloy includes a relatively lower strain temperature and a relatively higher strain rate. The internal electromagnetic stirring promotes the formation of more homogeneous as-deformed microstructures and more dynamic recrystallization grains.

Transverse gradient extrusion (TGE) process was firstly proposed to fabricate Mg–3Al–1Zn (AZ31) alloy sheet, thereby tailoring the strong basal texture of conventional extruded (CE) sheet. A novel texture formed in the TGE sheet, which tilted about 65° from normal direction (ND) to extrusion direction (ED) and elongated along transverse direction (TD). The basal texture component disappeared completely. Because of the formation of unique texture and uniform fined grain structure by TGE process, the extruded sheet exhibited a large Erichsen value (IE) of 6.7 mm at room temperature, which was approximately 258% of the CE sheet.

In this study, Ti particles reinforced Mg AZ31/Al 6082 composite sheets were successfully prepared by hot rolling, with the aim of revealing the effect of Ti particles addition on the mechanical behavior and microstructure of Mg AZ31/Al 6082 composite sheets. The results showed that Ti particles were uniformly distributed at the interface of the Mg/Al-Ti composite sheets, which could greatly reduce the amount of Mg-Al intermetallic compounds during annealing treatment. Compared to the Mg/Al sheet, the tensile strength and elongation of the Mg/Al-Ti sheet could be improved simultaneously after the annealing treatment. Ti particles addition hardly affected the grain size, texture type, and tensile fracture morphology of the Mg layer and Al layer in the composite sheets before and after annealing. This present study provides a new perspective on the mechanical behavior and microstructure of Mg/Al composites through the addition of metal particles.

The viscous fingering phenomenon often occurs when a low-viscosity fluid displaces a high-viscosity fluid in a homogeneous porous media, which is an undesirable displacement process in many engineering applications. The influence of wetting gradient on this process has been studied over a wide range of capillary numbers (7.5 × 10−6 to 1.8 × 10−4), viscosity ratios (0.0025 to 0.04), and porosities (0.48 to 0.68), employing the lattice Boltzmann method. Our results demonstrate that the flow front stability can be improved by the gradual increase in wettability of the porous media. When the capillary number is less than 3.5 × 10−5, the viscous fingering can be successfully suppressed and the transition from unstable to stable displacement can be achieved by the wetting gradient. Moreover, under the conditions of high viscosity ratio (M > 0.01) and large porosity (Φ > 0.58), wetting gradient improves the stability of the flow front more significantly.

In this paper, a new nanoscale metal Ti particle-reinforced Mg-3Al-1Zn matrix composite was successfully designed and prepared, which is mainly characterized by the fact that in addition to the “light” advantages of magnesium matrix composite, it also realizes bidirectional improvement of strength and ductility of the composite, and can be used as an alternative material for military light vehicle armor and individual armor. The SEM test shows that the nano-Ti particles are uniformly distributed at the grain boundary under the extruded state, which nails the grain boundary, inhibits the grain growth, and significantly refines the grain. XRD tests show that the addition of nano-Ti particles increases the crystallinity of the composite, which is consistent with the SEM test results. In addition, the EBSD test shows that the weakening of the texture of Ti/Mg-3Al-1Zn matrix composites and the increase in the starting probability of slip system are the main reasons for the improvement in ductility. Mechanical tests show that the yield strength, tensile strength, and elongation of the 0.5 wt% Ti/Mg-3Al-1Zn matrix composites exceed the peak values of ASTM B107/B107M-13 by 38.6%, 26.7%, and 20%, respectively.

The copper-clad magnesium composite wire with a diameter of 3.12 mm and good interface bonding was prepared by cold rotary swaging. The effects of cold rotary swaging and annealing temperature on microstructure and properties of the wire were studied by electron backscatter diffraction, transmission electron microscopy, as well as mechanical and electrical properties tests. The results show that the multi-pass cold rotary swaging composite has a great effect on grain refinement, microstructure recovery and structural unit reorientation, and can also make the wire obtain good interfacial bonding quality, improve mechanical properties, and the tensile strength can reach 289 MPa. The width of the interface layer widened with the increase of temperature, and the increase improved significantly at annealing temperatures of 450 °C and 500 °C, and the intermetallic compounds Mg2Cu and MgCu2 were found in the longitudinal section of the wire, respectively. After a reasonable annealing process of 400 °C/1 h, the interface layer did not thicken significantly, and the ductility and conductivity of the wire were the best, and the elongation after fracture and conductivity could reach 17% and 81.1% IACS, which increased by 15.2% and 3.8% compared with before annealing, respectively.

Accurate electricity consumption forecasting can be treated as a reliable guidance for power production. However, traditional electricity forecasting models suffer from simultaneously capturing the periodicity and the volatility of sequential electricity consumption data, while the periodicity and the volatility are important for electricity forecasting. In order to effectively model this sequential data and predict electricity consumption accurately, we propose a multi-scale prediction (Long Short Term Memory, LSTM) algorithm based on Time-Frequency Variational Autoencoder (TFVAE-LSTM). The proposed algorithm treats the sequential data as a superposition of data in different frequencies, it defines an encoder in frequency domain to extract frequency features to model the periodicity and volatility, and defines a decoder in time domain to capture the sequential features of data. Based on the extracted Time-Frequency features in a TFVAE, a multi-scale LSTM model is defined to further extract sequential features from different scales to predict electricity consumption. Experiments show the effectiveness of the proposed TFVAE-LSTM for electricity consumption forecasting tasks.

In recent years, knowledge graphs are applied to provide knowledge support and data support for power grid monitoring and decision-making. To construct a power metering knowledge graph, the power metering entities should be effectively recognized and extracted. However, the existing machine learning models do not fully consider the situation that some power metering entities’ names are partially overlapping and boundaries of some power metering entities are fuzzy. In this paper, we propose a Bi-order-Transformer-CRF to recognize power metering entities. Specifically, to alleviate the problem of fuzzy entity boundaries, we train our power metering word-vectors, and then we design Neural Cosine Similarity Function for distinguishing similar entities and Bi-order Feature Extracting Mechanism for recognizing overlapping entity names in the proposed Bi-order-Transformer-CRF. Moreover, we analyze the complexity of the proposed methods and verify that Bi-order-Transformer-CRF achieves better power metering entity recognition results compared with the commonly used machine learning methods in experiments.

Named Entity Recognition (NER) is one key step for constructing power domain knowledge graph which is increasingly urgent in building smart grid. This paper proposes a new NER model called Att-CNN-BiGRU-CRF which consists of the following five layers. The prefix Att means the model is based on attention mechanism. A joint feature embedding layer combines the character embedding and word embedding based on BERT to obtain more semantic information. A convolutional attention layer combines the local attention mechanism and CNN to capture the relationship of local context. A BiGRU layer extracts higher-level features of power metering text. A global multi-head attention layer optimizes the processing of sentence level information. A CRF layer obtains the output tag sequences. This paper also constructs a corresponding power metering corpus data set with a new entity classification method. The novelties of our work are the five layer model structure and the attention mechanism. Experimental results show that the proposed model has high recall rate 88.16% and precision rate 89.33% which is better than the state-of-the-art models.

Multivariate electricity consumption series clustering can reflect the trend of power consumption changes in the past time period, which can provide reliable guidance for electricity production. The dimensionality reduction-based method is an effective technology to address this problem, which obtains the low-dimensional features of each variate or all variates for multivariate time series clustering. However, most existing dimensionality reduction-based methods ignore the joint learning of the common representations and the variable-based representations. In this paper, we build a multivariate extreme learning machine based autoencoder model for electricity consumption clustering (MELM-EC), which performs common representation learning and variable-based representation learning simultaneously. MELM-EC maps the common representation and multiple variable-based representations to the original multivariate time series and computes the common output weights within a few iterations. Experimental results on realistic multivariate time series datasets and multivariate electricity consumption series datasets demonstrate the effectiveness of the proposed MELM-EC model.

In the present study, three types of bimetal composites, Al 6082 sleeve/Al 6082 core, Mg AZ31 sleeve/Mg AZ31 core and Al 6082 sleeve/Mg AZ31 core, were fabricated by drilling and assembling. The rule of mixtures (ROM) for the flow curves and yield strengths during compressive test were addressed. Our results show that the ROM can predict well the experimental flow curves and yield strengths of bimetal composites without bonding, irrespectively of the different strain hardening behavior between the two components.

The Echo State Networks (ESNs) is an efficient recurrent neural network consisting of a randomly generated reservoir (a large number of neurons with sparse random recurrent connections) and a trainable linear layer. It has received widespread attention for its simplicity and effectiveness, especially for time series prediction tasks. However, there is no explicit mechanism in ESNs to capture the inherent multi-scale characteristics of time series. To this end, we propose a model consisting of multi-reservoir structure named long-short term echo state networks (LS-ESNs) to capture the multi-scale temporal characteristics of time series. Specifically, LS-ESNs consists of three independent reservoirs, and each reservoir has recurrent connections of a specific time-scale to model the temporal dependencies of time series. The multi-scale echo states are then collected from each reservoir and concatenated together. Finally, the concatenated echo states representations are fed to the linear regression layer to obtain the results. Experiments on two time series prediction benchmark data sets and a real-world power load data sets demonstrate the effectiveness of the proposed LS-ESNs.

In the field of metal matrix composites, it is a great challenge to improve the strength and elongation of magnesium matrix composites simultaneously. In this work, xTC4/AZ31 (x = 0.5, 1, 1.5 wt.%) composites were fabricated by spark plasma sintering (SPS) followed by hot extrusion. Scanning electron microscopy (SEM) showed that nano-TC4 (Ti-6Al-4V) was well dispersed in the AZ31 matrix. We studied the microstructure evolution and tensile properties of the composites, and analyzed the strengthening mechanism of nano-TC4 on magnesium matrix composites. The results showed that magnesium matrix composites with 1 wt.%TC4 had good comprehensive properties; compared with the AZ31 matrix, the yield strength (YS) was increased by 20.4%, from 162 MPa to 195 MPa; the ultimate tensile strength (UTS) was increased by 11.7%, from 274 MPa to 306 MPa, and the failure strain (FS) was increased by 21.1%, from 7.6% to 9.2%. The improvement in strength was mainly due to grain refinement and good interfacial bonding between nano-TC4 and the Mg matrix. The increase in elongation was the result of grain refinement and a weakened texture.

Ex situ and in situ synchrotron X-radiography study on Al-Cu-Zr alloys with addition of Al-5Ti-1B and TiCN nanoparticles (TiCNnp) were carried out at different cooling rates. Al-Zr alloy can be effectively refined by TiCNnp via Ultrasonic treatment as compared with Al-5Ti-1B which has Zr poisoning effect. The influence of cooling rate on the nucleation and growth of grains have been studied quantitatively. The results show that the grain size was decreased and the growth rate was increased with the increasing of cooling rate. At the same cooling rate, the grain size with addition of 0.5% TiCNnp was smaller than that with the same addition of Al-5Ti-1B. The blocking factor f of TiCNnp decreases with increasing cooling rate. Based on the free growth model, a new numerical model considering the growth restriction effect of nanoparticles was established. The growth of grain was inhibited by the combining effect of solute and nanoparticles. The growth rate of grain is reduced due to part of the solid/liquid interface coated by nanoparticles. The blocking factor f is linearly decreased with the coverage ratio ω which is proportional to the critical grain radius. The grain size decreases with increasing cooling rate and decreasing f . This study is especially beneficial for Al alloys that have poisoning phenomenon inoculated by traditional refiner.

Good solid-liquid mixing homogeneity and liquid level stability are necessary conditions for the preparation of high-quality composite materials. In this study, two rotor-stator agitators were utilized, including the cross-structure rotor-stator (CSRS) agitator and the half-cross structure rotor-stator (HCSRS) agitator. The performances of the two types of rotor-stator agitators and the conventional A200 (an axial-flow agitator) and Rushton (a radial-flow agitator) in the solid-liquid mixing operations were compared through CFD modeling, including the homogeneity, power consumption and liquid level stability. The Eulerian–Eulerian multi-fluid model coupling with the RNG k–ε turbulence model were used to simulate the granular flow and the turbulence effects. When the optimum solid-liquid mixing homogeneity was achieved in both conventional agitators, further increasing stirring speed would worsen the homogeneity significantly, while the two rotor-stator agitators still achieving good mixing homogeneity at the stirring speed of 600 rpm. The CSRS agitator attained the minimum standard deviation of particle concentration σ of 0.15, which was 42% smaller than that achieved by the A200 agitators. Moreover, the average liquid level velocity corresponding to the minimum σ obtained by the CSRS agitator was 0.31 m/s, which was less than half of those of the other three mixers.

Grain refinement of cast alloys, especially aluminum–silicon and magnesium-based alloys, is an effective approach to improve the strength of alloys. Grain size is the most representative parameter used to characterize grain refinement in the industry, thereby attracting increasing attention for developing accurate grain size prediction models. In this paper, several important grain size prediction models under different adaptation conditions are reviewed. These models are obtained either by regression of experimental data or by physical/mathematical inference under certain assumptions of specified cases, focusing on the effects of alloy composition, solidification temperature gradient, grain growth rate, and fining agent composition, among others. The trends of grain size prediction models were also discussed. The results revealed machine learning as an effective tool to establish a data-driven prediction model of grain size in cast aluminum alloys.

Internal electromagnetic stirring is an advanced melt treatment method, which can be used in direct chill casting to prepare large-scale Al alloy billets. Intercooling intensity is a primary parameter of internal electromagnetic stirring; its effects on temperature fields and microstructures have been investigated via numerical simulations and industrial experiments, respectively. The simulated results show an increase in the intercooling affected area and a decrease in sump depth with an increase in the intercooling heat transfer coefficient. The heat transfer coefficient should not exceed 500 W/(m2 °C) because the solid fraction of the intercooling end bottom may exceed 50%. The experiment’s results demonstrate that the average grain sizes in the edge, 1/2 radius, and center are 151 ± 13 μm, 159 ± 14 μm, and 149 ± 16 μm, respectively, under a liquid nitrogen flow rate of 160 L/min, which is much finer than that of 80 L/min and more homogeneous than that of 240 L/min. Furthermore, an experimental liquid nitrogen flow rate of 80 L/min, 160 L/min, and 240 L/min approximately correspond to the simulated heat transfer coefficient of 200 W/(m2 °C), 300 W/(m2 °C), and 400 W/(m2 °C), respectively.

The interfacial mechanics and electrical properties of SiC reinforced copper matrix composites were studied via the first principles method. The work of adhesion (Wad) and the interfacial energies were calculated to evaluate the stabilities of the SiC/Cu interfacial models. The carbon terminated (CT)-SiC/Cu interfaces were predicted to be more stable than those of the silicon terminated (ST)-SiC/Cu from the results of the Wad and interfacial energies. The interfacial electron properties of SiC/Cu were studied via charge density distribution, charge density difference, electron localized functions and partial density of the state. Covalent C–Cu bonds were formed based on the results of electron properties, which further explained the fact that the interfaces of the CT-SiC/Cu are more stable than those of the ST-SiC/Cu. The interfacial mechanics of the SiC/Cu were investigated via the interfacial fracture toughness and ultimate tensile stress, and the results indicate that both CT- and ST-SiC/Cu interfaces are hard to fracture. The ultimate tensile stress of the CT-SiC/Cu is nearly 23 GPa, which is smaller than those of the ST-SiC/Cu of 25 GPa. The strains corresponding to their ultimate tensile stresses of the CT- and ST-SiC/Cu are about 0.28 and 0.26, respectively. The higher strains of CT-SiC/Cu indicate their stronger plastic properties on the interfaces of the composites.

As-cast irons and aluminum alloys are used in various industrial fields and their phase and microstructure properties are strongly affected by the undercooling degree. However, existing studies regarding the undercooling degree are mostly limited to qualitative analyses. In this paper, a quantitative analysis of the undercooling degree is performed by collecting experimental data and employing machine learning. Nine machining learning models including Random Forest (RF), eXtreme Gradient Boosting (XGBOOST), Ridge Regression (RIDGE) and Gradient Boosting Regressor (GBDT) methods are used to predict the undercooling degree via six features, which include the cooling rate (CR), mean atomic covalence radius (MAR) and mismatch (MM). Four additional effective models of machine learning algorithms are then selected for a further analysis and cross-validation. Finally, the optimal machine learning model is selected for the dataset and the best combination of features is found by comparing the prediction accuracy of all possible feature combinations. It is found that RF model with CR and MAR features has the optimal performance results for predicting the undercooling degree.

The TiB _2 /Al particle reinforced composites were prepared successfully through metal-salt reaction with different process conditions (mechanical stirring, one-stage and two-stages of ultrasonic vibration). It was usually taken more than 60 min to complete metal-salt reaction under mechanical stirring condition, lots of reinforcement agglomerations and residual intermediate such as Al _3 Ti was in the matrix. The reaction time was greatly shortened from 60 min to 5 min and particle agglomerations were eliminated successfully by the introduction of ultrasonic vibration at 850 °C. Through the introduction of ultrasonic vibration at 730 °C, not only most of the residual Al _3 Ti phase was broken or dissolved, but also the size of TiB _2 was refined. The composite prepared by two-stage ultrasonic vibration has the optimal improvements of yield strength and ultimate tensile strength, which increased by are 108% and 98% respectively, hardness increased 61.5%. When only introducing the first stage of UVT, the elongation decreased from 34% to 20% owning to lots of rod-like Al _3 Ti in the matrix, after the second stage of UVT, the elongation restored to 33%. The effects of ultrasonic vibration on phase transformation, microstructure, and mechanical properties were studied by x-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and Electron Backscattered Diffraction (EBSD). Moreover, the effects of Orowan strengthening, thermal expansion mismatch strengthening, and grain refinement strengthening on mechanical properties were also discussed.

A damage estimation method based on continuous wavelet transformation (CWT) of the normalized Lamb wave signals is proposed here. Lamb waves are actuated and sensed using piezoelectric (lead zirconate titanate, PZT) transducers arranged in the form of square detection cells on a plate-like structure. Excitation sequences based on pitch–catch and pulse–echo configurations are tested for the same arrangement of the transducers. The possibilities of the existence of damage for each actuator–senor pair are formed by using the normalized coefficient of CWT. The size of the possible damage region is directly controlled through envelopes defined by the coefficients of CWT, and no additional parameter is required to define its size. The aggregate damage image is constructed by the fusion of damage possibilities from all actuator–sensor pairs using damage indices based on conjunctive and compromised fusion schemes. The results indicate that the proposed method can estimate the location and severity of multiple damage with signals directly from the damaged plate, without the need of baseline signals from the undamaged plate, and the time-compensated signals provide better damage imaging than the raw signals. The most accurate and computationally inexpensive combination is the pulse–echo configuration with damage index based on conjunctive image fusion scheme. The method is computationally inexpensive and can be applied for multiple damage estimations in large structures to reduce the evaluation cost and inspection time during on-line structural health monitoring.

Under compressive testing at 400C and a strain rate range of 0.05-5 s-1, the hot deformation behavior and microstructure evolution of an as-cast (AC), as-extruded (with a bimodal grain structure (named as Ex-1) or a relatively uniform fine grain structure (Ex-2)) WE43 alloy have been investigated and compared. The results indicate that the AC sample exhibits the highest peak stress, while the Ex-2 sample has the lowest value. Within the AC material, fine grains were firstly formed along the pancake-like deformed grains (as a necklace structure). The necklace structure was also formed within the Ex-1 and Ex-2 materials at high strain rates of 0.5 and 5 s-1. However, a lamellar structure that the coarse elongated grains divided by parallel boundaries was formed within the Ex-1 material. A relatively more homogeneous fine grain structure is achieved after a true strain of 1.0 within the Ex-2 material at a low strain rate of 0.05 s-1. In addition, a discontinuous dynamic recrystallization mechanism by grain boundary bulging is found to occur. After a true strain of 1.2, a (0001) fiber texture, a typical rare earth (RE) texture, and a relatively random texture are formed within the AC, Ex-1, and Ex-2 WE43 alloy material, respectively.