Microstructure and mechanical properties of Al-5.8Mg-Mn-Sc-Zr alloy after annealing treatment

An Al-5.8Mg-0.4Mn-0.35(Sc+Zr) (mass fraction,%) alloy sheet was prepared using water chilling copper mould ingot metallurgy processing which was protected by active flux. The influence of stabilizing annealing on mechanical properties and microstructure of the cold rolling sheet was studied. The results show that the strength and hardness of the alloy decrease,while the elongation increases with increasing the stabilizing annealing temperature. With the increase of stabilizing annealing time,the strength and hardness of the alloy drop slightly but its ductility exhibits no change. Partial recovery and recrystallization orderly occur with the increase of annealing temperature during stabilizing treatment. Only different degrees of recovery occur in the alloys annealed below 400 °C for 1 h. Partial recrystallization occurs after annealed at 450 °C for 1 h. By annealing at 300 °C for 1 h,the alloy can obtain the optimum application values of σb,σ0.2 and δ,which are 436 MPa,327 MPa and 16.7%,respectively.