Effect of laser rapid quenching on microstructure evolution and mechanical properties of 7B04 aluminum alloy

This paper is aimed at solving the problem of poor room temperature plasticity of 7B04 aluminum alloy at the T74 state. In this study, a method of rapid heat treatment by laser scanning was adopted. Mechanical properties coupled with the related microstructure evolution of 7B04 aluminum alloy after laser heat treatment were analyzed simultaneously. The results show that the large impurity phase where the microcracks usually generate in the material at the T74 state can be eliminated under appropriate parameters in laser heat treatment. At the same time, a large number of fine strengthening phases precipitated during the subsequent aging process, which plays a strong pinning role in dislocations and increases the deformation resistance, thus effectively improving the strength of 7B04 aluminum alloy. Under the action of both factors, its plasticity can be greatly improved while the strength remains essentially unchanged, and the elongation after fracture can be increased by up to 51.3%.