Effect of grain size on high strain rate deformation of rolled Mg-4Y-3RE alloy in compression
Effect of grain size on high strain rate deformation of rolled Mg-4Y-3RE alloy in compression
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DOI：
10.1016/j.msea.2015.03.020
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发表时间：
2015-05
期刊：
影响因子：
6.4
通讯作者：
H. Asgari;J. Szpunar;A. Odeshi;Lunjie Zeng;E. Olsson
中科院分区：
文献类型：
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作者：
H. Asgari;J. Szpunar;A. Odeshi;Lunjie Zeng;E. Olsson
镁合金广泛应用于汽车和航空航天行业，在这些行业中，它们可能暴露在高应变率条件下，如汽车碰撞和弹道撞击。晶粒度是影响镁合金在高应变率下力学行为的重要因素。因此，评价晶粒度对冲击加载条件下镁合金动态力学响应的影响具有重要意义。本文研究了晶粒度分别为8、25和46μm的Mg-4Y-3RE合金轧制后在压缩冲击载荷下的织构演化、显微组织变化和动态力学行为。用分离式霍普金森压杆在室温下进行了动态冲击加载试验，应变速率为1200t S−1。织构测量表明，所有样品在冲击加载过程中都发展了双峰(00.2)基面织构。然而，对于粗晶样品，观察到的强度略高。强度和塑性均随晶粒度的增大而降低，而孪生分数和应变硬化率则随晶粒度的增大而增大。双孪晶和收缩孪晶的活动随着晶粒度的增大而增加。此外，用‘G.B’分析方法证实了在冲击载荷作用下，Mg-4Y-3RE合金中存在着锥体<；c+a>；滑移系统的激活。
Magnesium alloys are widely used in automotive and aerospace industries, where they can be exposed to high strain rate conditions such as car crash and ballistic impact. Grain size is an important factor that can affect the mechanical behavior of magnesium alloys at high strain rates. Therefore, it is very important to evaluate the effects of grain size on the dynamic mechanical response of magnesium alloys under shock-loading conditions. In this research, texture evolution, microstructural changes and dynamic mechanical behavior of rolled Mg–4Y–3RE alloy samples, with grain sizes of 8, 25 and 46 μm, deformed under compressive shock-loading are investigated. Dynamic shock loading tests were conducted using Split Hopkinson Pressure Bar at room temperature at a strain rate of 1200 s−1. Texture measurements indicate development of a double-peak (00.2) basal texture in all the samples during shock loading. However, slightly higher intensities were observed for coarse-grained samples. Both strength and ductility were found to decrease with increasing grain size, while twining fraction and strain hardening rate increase with increasing grain size. The activity of double and contraction twins increased with increase in grain size. Furthermore, activation of pyramidal <c+a> slip system during the shock loading of the Mg–4Y–3RE alloy was confirmed using the ‘g.b’ analysis method.