Microstructure and deformation mechanism of 0 0 0 1 magnesium single crystal subjected to quasistatic and high-strain-rate compressiveloadings
Microstructure and deformation mechanism of 0 0 0 1 magnesium single crystal subjected to quasistatic and high-strain-rate compressiveloadings
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DOI：
10.1016/j.msea.2013.01.028
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发表时间：
2013-04
期刊：
影响因子：
6.4
通讯作者：
Qizhen Li
中科院分区：
文献类型：
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作者：
Qizhen Li
分别在准静态应变率(0.001s−1)和动态应变率(1000s−1)下对0001镁单晶样品进行了压缩加载力学试验。然后，通过各种微观结构表征技术对测试样品进行了研究。动态加载比准静态加载具有更高的最大强度和更大的应变硬化率。两种加载条件下的显微组织特征明显不同，表明准静态试验和动态试验的变形机制不同。显微组织分析表明：(A)在准静态加载和动态加载下，样品中发生了棱柱状和二次锥体位错操作，而在准静态加载下，还发生了拉伸孪晶和拉压双孪晶；(B)在高应变率动态加载下，样品保持了单晶，而在准静态加载下，样品被细化为多晶；(C)准静态加载下的孪晶操作导致了晶粒的细化。
0001 magnesium single crystal samples were mechanically tested under compressive loadings at a quasistatic strain rate (0.001s−1) and a dynamic strain rate (1000s−1), respectively. The tested samples were then investigated through various microstructural characterization techniques. Dynamic loading led to much higher maximum strength and larger strain hardening rate than quasistatic loading for the tested material. The microstructure features were clearly different from each other for the two loading conditions, which indicated that the deformation mechanisms for the quasistatic testing were different from those for the dynamic testing. The microstructure analysis showed that (a)prismatic and secondary pyramidal dislocation operations happened in the samples under quasistatic loading and dynamic loading, while tension twinning and tension–compression double twinning also happened in the sample under quasistatic loading; (b)the sample under high-strain-rate dynamic loading remained as single crystal, while that under quasistatic loading was refined to become polycrystalline; and (c)twinning operations under quasistatic loading led to grain refinement.