Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7971639 | Materials Science and Engineering: A | 2018 | 9 Pages |
Abstract
High-performance as-extruded and peak-aged Mg-9.2Gd-3.3Y-1.2Zn-0.9Mn (wt%) alloys have been fabricated by semi-continuous casting, heat-treating, extruding and ageing processes. The effects of different heat treatments on the microstructure and mechanical properties have been investigated. Lamellar and bulk-shaped 14H-type long-period stacking ordered (LPSO) phase and few RE-rich (RE: rare earth element) particles form by different heat treatments. After hot extrusion, the heat-treated alloy with bulk-shaped LPSO phase exhibits an equal-axial microstructure, while the heat-treated alloy with lamellar LPSO phase across the grains shows bimodal grain microstructure consisting of fine equal-axial grains and coarse deformed grains. The more profuse lamellar LPSO phase in heat-treated alloy generates higher volume fraction of deformed grains and finer equal-axial grains, hence leads to higher strength but lower ductility. After ageing, the alloy with profuse LPSO and βⲠphases achieves the superior mechanical properties with ultimate tensile strength (UTS) of 525â¯MPa, tensile yield strength (TYS) of 420â¯MPa and elongation to failure (EL) of 6.3%. The alloy strengthening is mainly attributed to the bimodal grain microstructure, LPSO phase, Mg5Gd (β) phase and βⲠphase.
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Authors
Kui Wang, Jingfeng Wang, Song Huang, Shiqing Gao, Shengfeng Guo, Shijie Liu, Xianhua Chen, Fusheng Pan,