Ti/Al laminated composite fabricated by explosive welding has received widespread attention due to their potential in achieving excellent performance. However, investigations on the crack evolution and fracture behavior were still limited. In this paper, the morphology and elemental distribution of the bonding interface were investigated. And the crack initiation and propagation of Ti/Al laminated composite was investigated by in-situ tensile test. It is shown that local melted zone (LMZ) was formed along the wavy interface, which was mainly consisted of TiAl2 + TiAl3 intermetallic compounds. The brittle intermetallic compounds on the LMZs are places where cracks initiate. As the internal stress accumulation, cracks generate at the tip of the wavy interface where the Ti layer is thinnest, and they locally form delamination along the interface. Subsequently, the crack tip is released from the Ti layer, leading to a catastrophic fracture to the whole Ti layer. Finally, the crack propagates to the Al layer until the material eventually fractured. Graphical Abstract

Anisotropy is the difference in the microstructure or mechanical properties of materials in different directions. Anisotropic behavior occurs in rolled sheets, and this anisotropy is very obvious in laminated composites. In this work, the influence of anisotropy on the microstructure and mechanical properties of Ti/Al laminated composites fabricated by rolling was investigated. The results show that the microstructure and mechanical properties of the Ti/Al laminated composites were obviously anisotropic. The grains in the Al layer of the composites were elongated along the rolling direction and were compressed perpendicular to the rolling direction. The grains in the Ti layer of the composites had no obvious preferential orientation and comprised mainly twins. With the rolling direction as 0°, the mechanical properties of the Ti/Al laminated composites varied greatly as the angle of the composites increased. The tensile strength, elongation and bond strength of the Ti/Al laminated composites decreased with increasing angle of the composites. In addition, the microhardness of the Ti/Al laminated composites increased with increasing angle of the composites.

AZ63 magnesium alloy sheets were fabricated by accumulative roll bonding (ARB) process at 350 °C up to 5 cycles. The aim of this work is to study the effect of ARB process on the microstructure and corrosion behavior of AZ63 magnesium alloy. The ARBed sheets were investigated via microstructure observations, electrochemical tests, hydrogen evolution measurements and immersion tests. After ARB process, the average grain size decreased. The coarse Mg₁₇Al₁₂ phase was broken under the action of rolling force and it distributed more dispersed in the magnesium matrix. The corrosion resistance of samples increased significantly with increasing the number of ARB cycles. The influence of microstructure on the corrosion behaviors was discussed. Fine grain produced more passive oxide layers which acted as a corrosion barrier. The Mg₁₇Al₁₂ phase acted primarily as a micro-galvanic cathode during the corrosion process because of its low volume fraction and isolated distribution. The volume fraction of Mg₁₇Al₁₂ phase decreased after ARB process, which results in the reduction of the effect of galvanic corrosion.

Copper matrix composites (Cu-MCs) have garnered significant attention due to their exceptional electrical, wear-resistant, and mechanical properties. Among them, Al₂O₃/Cu composites, reinforced with Al₂O₃, are a focal point in the field of high-strength, high-conductivity copper alloys, owing to their high strength, excellent electrical conductivity, and superior resistance to high-temperature softening. Cold deformation is an effective method for enhancing the mechanical properties of Al₂O₃/Cu composites. However, during cold deformation of large-cross-sectional Al₂O₃/Cu composites, the inhomogeneity in microstructure and properties induced by varying stress states cannot be overlooked. In this study, cold deformation of 1.12 wt% Al₂O₃/Cu large-cross-sectional composites was performed using a rolling process, coupled with finite element numerical simulations, to investigate the distribution characteristics of microstructure and properties during the rolling process. The results indicate that under cold deformation, the hardness of the material increases linearly from the surface layer to the core, while the change in electrical conductivity is minimal. The increase in hardness is closely related to variations in dislocation density and grain size, with dislocation density being the dominant strengthening mechanism. Quantitative analysis reveals that strain inhomogeneity during cold deformation is the primary cause of microstructural differences, leading to variations in mechanical properties at different positions. This study provides a theoretical basis for understanding the inhomogeneity of cold deformation in large-sized Al₂O₃/Cu composites and for controlling their microstructure–property relationships.