Ma Tao, Zhao Sicong, Wang Liping, Wang Zhiwei, Guo Erjun, Feng Yicheng, Li Jingfang
School of Material Science and Chemical Engineering, Harbin University of Science and Technology, Harbin 150000, China.
Key Laboratory of Advanced Manufacturing and Intelligent Technology (MOE), Harbin University of Science and Technology, Harbin 150000, China.
Materials (Basel). 2021 Sep 3;14(17):5037. doi: 10.3390/ma14175037.
The effect of solution treatment time on the microstructure and mechanical properties of aged the Mg-2.0Nd-2.0Sm-0.4Zn-0.4Zr (wt.%) alloy were investigated to give full play to the performance of the alloy. As the solution treatment time increased from 2 h to 12 h at 788 K, the grain size of the solution-treated alloy significantly increased, and the network-like -Mg(Nd, Sm, Zn) phase gradually dissolved into the -Mg matrix. It should be noted that no obvious residual phase can be observed when the solution treatment time was more than 8 h. After the solution-treated alloy was further aged at 473 K for 18 h, a large number of nanoscale precipitates were observed in the -Mg matrix. The solution treatment time was 2 h, the -Mg matrix mainly consisted of spherical-shaped and basal plate-shaped precipitates. Upon the increase of solution treatment time to 8 h, the key strengthening phases transformed from spherical-shaped precipitates and basal plate-shaped precipitates to prismatic plate-shaped ' precipitates. The orientation relationship between ' precipitates and -Mg matrix was (1¯10) // (11¯00) and [112] // the [224¯3]. Further increasing of solution treatment time from 8 h to 12 h, the key strengthening phases mainly were still ' precipitates. The solution treatment of aged alloy was carried out at 788 K for 8 h, which achieved optimal ultimate tensile strength (UTS) of 261 ± 4.1 MPa, yield strength (YS) of 154 ± 1.5 MPa, and elongation of 5.8 ± 0.1%, respectively.
