Microstructure, age-hardening behavior and mechanical properties of Mg-7Sn-Zn(Y) alloy

Abstract

Abstract: The microstructure, age-hardening behavior and mechanical properties of Mg-7Sn-Zn(Y) alloy were investigated. The as-cast Mg-7Sn alloy was mainly composed of α-Mg and eutectic(α-Mg+Mg₂Sn) phase. The addition of Zn refines Mg₂Sn phase, increases volume fraction of Mg₂Sn phase and promotes precipitation of Mg₂Sn phase on non-basal plane, and thus enhances the ageing hardening capacity of the alloy. The peak-ageing hardness of the Mg-7Sn-1Zn alloy increases from 64.6 HV to 69.7 HV, and the peak-ageing time decreases from 166 h to 142 h. The addition of Zn and Y elements forms the needlelike MgSnY phase. Although the peak-ageing time of the alloy is effectively decreased(166 h to 120 h), the peak-ageing hardness of the alloy reduces.The Mg-7Sn-1Zn alloy exhibits the best mechanical properties,Which was mainly attributed to the precipitation strengthening of fine Mg₂Sn phasewith high volume fraction.

Key words: Mg-Sn-Zn-Y alloy, microstructure, age-hardening behavior, mechanical properties

CLC Number:

TG146.2

BI Guang-li, XU Zuo-cheng, GU Jia-rui, JIANG Jing, JIANG Chun-hong, LI Yuan-dong. Microstructure, age-hardening behavior and mechanical properties of Mg-7Sn-Zn(Y) alloy[J]. Journal of Lanzhou University of Technology, 2020, 46(6): 1-8.

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