Effect of solution treatment on microstructures and mechanical properties of industrial 7050 thick plate

¹ International Joint Laboratory for Light Alloys (Ministry of Education), College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
² Electron Microscopy Center of Chongqing University, Chongqing 400044, China
³ Southwest Aluminum (Group) Co., Ltd, Chongqing 401326, China
⁴ Key Laboratory for Light-weight Materials, Nanjing Tech University, Nanjing 210009, China

^* Corresponding author: zhihongjia@cqu.edu.cn.org

Abstract

In this work, effect of solution treatments on the microstructures and mechanical properties of industrial 7050 aluminum alloy thick plate was investigated by tensile test, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and transmission electron microscopy (TEM). The results show that the area fraction of residual phases decreases with increasing solution temperature from 475°C to 500°C. The overheating phenomenon identified by compound melting ball and crystal separating phase was observed at a temperature of 485°C or above. The compound melting balls are composed of S(Al₂CuMg) phase dissolved with Zn atoms and Al matrix. The crystal separating phase is consisted of Al₂Cu phase and the amorphous structure containing solute atom Mg. The maximum tensile strength of 529 MPa was obtained for the alloy solution treated at 475°C for 3h followed by peak aging at 120°C for 24h.