Comprehensive study of hot deformation behavior and fracture mechanism of Al/Cu laminated composite

The hot deformation behavior of Al/Cu laminated composite was studied by isothermal tensile experiments in the temperature range of 200–500 °C and strain rate range of 0.001–1/s. The Arrhenius constitutive model was established to predict the flow stress by determining the constants of composites. In addition, based on the dynamic material model (DMM), the hot working map is established. The results show that the power dissipation efficiency is high under the conditions of high temperature, medium and low strain rate. When the strain is 0.25, there are few areas of stability due to the increasing frictional resistance at the interface. It is found that the dynamic recrystallization (DRX) is promoted by hot tensile and laminate structure. The softening mechanism of Al side is mainly dynamic recovery (DRV) and discontinuous dynamic recrystallization (DDRX), while that of Cu side is DRX. During the tensile process, the Al side grains always maintain stable Brass, Copper and S textures; the Cu side grains always maintain the Cube texture with stable-end orientation and when the deformation exceeds 60 %, the Goss unstable texture appears. It is conducive to dislocation movement and increases the recrystallization ratio. Then, the fracture mechanism of Al/Cu laminated composite is revealed. Due to the presence of the interface, the Cu side shows brittle fracture at room temperature. The snake-like sliding occurs on both sides of Al and Cu under hot deformation, showing ductile fracture, and the defects on Cu side are more serious than those on Al side. These results lay a foundation for optimizing the hot working parameters, improving the performance of the forming parts and clarifying the fracture damage mechanism of Al/Cu laminated composite.