Effect of Annealing Treatment on the Interface Structure and Properties of 1070A/7075 Composite Plate Produced by Liquid-Solid Cast-Rolling

The effect of annealing temperature and time on the interfacial organization and properties of the liquid-solid cast-rolled 1070A/7075 aluminum alloy composite plates are investigated. Optical and electron microscopy, energy-dispersive x-ray spectroscopy, mechanical shear and tensile tests were used in the study. It is shown that annealing promotes the diffusion of elements between the 1070A/7075 aluminum alloys of the composite, and the interface region of the composite forms an obvious intermediate transition layer. It is found that in order to ensure the bonding strength of the composite plate after annealing, the width of the transition layer should be between 1.5 – 7.9 μm. After annealing at 300°C for 3 h, the element diffusion distance is 30 μm, and the width of the interface transition zone is 2.4 μm. In this case, the bond strength at the interface reaches a maximum value of 105 MPa, and the tensile strength, yield strength and relative elongation are 150 MPa; 70 MPa and 27% respectively.