Abstract

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Author(s):: ZENG Xiaoqin1; 2; ZHU Qingchun1; 2; LI Yangxin1; 2; DING Wenjiang1; 2; （1. National Engineering Research Center of Light Alloy Net Forming，School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240，China）
（2. State Key Laboratory of Metal Matrix Composites，School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240，China)

Keywords:: magnesium alloy; second phase; age-hardening; long period stacking ordered (LPSO) phase; Mg-based reinforcement

Abstract:: As the lightest structural metals, magnesium alloys have been widely used in fields of aerospace, automotive industry and digital electronic products. Compared with steels and aluminum alloys, magnesium alloys exhibit limited strengthening methods, so the second phase strengthening in magnesium alloys becomes particularly important. In this review paper, microstructure, strengthening effect as well as strengthening mechanism of the second phases (including aged precipitates, long-period stacking ordered (LPSO) phase and reinforcements in Mg-based alloy) in different magnesium systems are summarized as follows: ① in RE-free magnesium alloys, the most effective strengthening phases are mainly formed during ageing; ② Mg-RE based alloys show more options of strengthening second phases, as compared with RE-free magnesium alloys; ③ the strengthening effect of reinforcement depends on its own composition, morphology, size and bonding ability with the α-Mg matrix. In future, the research on the second phase strengthening in magnesium alloys should be focused on the following aspects: ① the introduction of advanced nano-strengthening phases; ② the manipulation of synergistic strengthening effect of the LPSO phase and other precipitates; ③ the design of inexpensive magnesium-based reinforcements.