Effect of annealing on microstructure evolution and age-hardening behavior of dilute Mg–Al–Ca–Mn alloy
Jing Zuo, T. Nakata, Chao Xu, Yifan Xia, Hailong Shi, Gen‐Shuh Wang, Guoyuan Tang, Guohua Fan, S. Kamado, Lin Geng
Abstract
Microstructure evolution and mechanical properties of the as-drawn dilute Mg-0.8Al-0.1Ca-0.6Mn (wt. %) alloy wires during annealing and peak-aging treatment were investigated in this paper. The results show that the high density of nano-sized Al–Mn precipitates strongly hindered grain boundary migration to restrict grain growth during annealing under 300 °C and 400 °C, while grain growth was obvious and the uniformity of recrystallization grain size increased due to partial dissolution of Al–Mn precipitates at 500 °C. In addition, there was a growth preference in grains with (0001) <2 1¯1¯ 0> orientation, which was closely associated with the texture changes. The alloy annealed at 500 °C for 10min exhibits remarkable age-hardening response and both the tensile yield strength and elongation to failure were improved simultaneously after peak-aging treatment, which was mainly attributed to the monolayered Guinier-Preston (G.P.) zones and planar Al2Ca precipitates.