Enhanced mechanical properties of Mg-Gd-Y-Zn-Mn alloy by tailoring the morphology of long period stacking ordered phase
Enhanced mechanical properties of Mg-Gd-Y-Zn-Mn alloy by tailoring the morphology of long period stacking ordered phase
复制标题
通过调整长周期堆叠有序相的形貌来增强 Mg-Gd-Y-Zn-Mn 合金的机械性能
DOI：
10.1016/j.msea.2018.07.050
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发表时间：
2018-08-22
期刊：
影响因子：
6.4
通讯作者：
Pan, Fusheng
中科院分区：
文献类型：
--
作者：
Wang, Kui;Wan, Jingfeng;Pan, Fusheng
采用半连续铸造、热处理、挤压、时效等工艺制备了高性能的Mg-9.2Gd-3.3Y-1.2Zn-0.9Mn （wt%）挤压峰时效合金。研究了不同热处理工艺对合金组织和力学性能的影响。不同热处理形成片状和块状14h型长周期有序堆积相（LPSO）和少量富RE （RE：稀土元素）颗粒。热挤压后，块状LPSO相的热处理合金表现为等轴组织，而片层状LPSO相的热处理合金表现为由细小等轴晶粒和粗变形晶粒组成的双峰组织。热处理合金的片层状LPSO相越丰富，变形晶粒的体积分数越高，等轴晶越细，强度越高，塑性越低。时效后，具有丰富的LPSO和β′相的合金具有优异的力学性能，极限抗拉强度（UTS）为525 MPa，抗拉屈服强度（TYS）为420 MPa，失效伸长率（EL）为6.3%。合金的强化主要表现为双峰晶组织、IPSO相、Mg5Gd （β）相和β′相。
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 beta' phases achieves the superior mechanical properties with ultimate tensile strength (UTS) of 525 MPa, tensile yield strength (TYS) of 420 MPa and elongation to failure (EL) of 6.3%. The alloy strengthening is mainly attributed to the bimodal grain microstructure, IPSO phase, Mg5Gd (beta) phase and beta' phase.