Precipitation and its effect on the mechanical properties of a cast Mg-Gd-Nd-Zr alloy
Precipitation and its effect on the mechanical properties of a cast Mg-Gd-Nd-Zr alloy
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DOI：
10.1016/j.msea.2007.11.080
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发表时间：
2008-08
期刊：
影响因子：
6.4
通讯作者：
K. Zheng;J. Dong;X. Zeng;W. Ding
中科院分区：
文献类型：
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作者：
K. Zheng;J. Dong;X. Zeng;W. Ding
采用透射电镜对经250℃等温时效处理的Mg-11Gd-2Nd-0.5Zr （wt.%）合金进行了显微组织表征，并采用维氏硬度、室温和高温拉伸试验对时效不同时间后合金的力学性能进行了评价。合金的四阶段析出顺序为：过饱和α-Mg固溶体→β″（D019）→β′（bco）→β1（fcc）→β(fcc)，其中后相可与前相共存。晶粒内部的析出伴随着晶界相（GBPs）和无析出带（PFZs）的形成和生长。通过对组织-性能关系的讨论，发现三角形密集的β′相是该合金的最佳强化组织。gps和pfz的存在使合金的力学性能恶化。
Microstructural characterization of a Mg–11Gd–2Nd–0.5Zr (wt.%) alloy processed by isothermal aging at 250°C has been performed using transmission electron microscopy, and the mechanical properties of the alloy after aging for different time have been evaluated using Vickers hardness, room- and high-temperature tensile tests. A four-stage precipitation sequence of the alloy can be described as follows: supersaturated α-Mg solid solution→β″(D019)→β′(bco)→β1(fcc)→β(fcc), where the later precipitate can coexist with the former. The precipitation inside the grains is accompanied by the formation and growth of grain boundary precipitates (GBPs) and precipitation free zones (PFZs). Discussion on the structure–properties relationships reveals that microstructure with dense β′ precipitates in triangular arrangement is the optimum strengthening structure for the alloy. The existence of GBPs and PFZs in the alloy deteriorates the mechanical properties.