Experimental Investigation on Heat Treatment Process of Compound-Formed 6A02 Component with Bracket Shape

The orthotropic heat treatment experiment of 6A02 Al bracket-shape component formed by thixoforming-plastic deformation compound forming technology was conducted. After heat treatment, yield strength σ_s and maximum tensile strength σ_b were improved by 145.6% and 42.0%, respectively, but the elongation was decreased. The largest σ_s and σ_b after heat treatment were 319.0 and 346.1 MPa, respectively. Under various heat treatment conditions, the solid solution degree and precipitated hardening phases were different. Solid solution degree of No. 4 sample was low (solid solution temperature T_S of 500 °C, solid solution time t_S of 80 min, aging temperature T_A of 180 °C and aging time t_A of 14 h) and dispersed needlelike β′′ phase with the size of ~ 400 nm × 30 nm × 30 nm precipitated. However, for verification sample A3B2C1D1(T_S of 520 °C, t_S of 40 min, T_A of 150 °C and t_A of 8 h), the solid solution degree was larger and the main dispersoid was α-Al(FeMn)Si. The precipitation strengthening was the main strengthening mechanism for 6A02 compound-formed component with heat treatment, occupying 63.3%.