Mechanism of grain growth during severe plastic deformation of a nanocrystalline Ni-Fe alloy
Mechanism of grain growth during severe plastic deformation of a nanocrystalline Ni-Fe alloy
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DOI：
10.1063/1.3065025
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发表时间：
2009-01
影响因子：
4
通讯作者：
Yanbo Wang;J. C. Ho;Xiaozhou Liao;H. Q. Li;S. Ringer;Yuntian Zhu
中科院分区：
文献类型：
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作者：
Yanbo Wang;J. C. Ho;Xiaozhou Liao;H. Q. Li;S. Ringer;Yuntian Zhu
在纳米晶材料中，形变诱导的晶粒长大已被广泛报道。然而，晶粒生长机制仍然是一个悬而未决的问题。本研究采用高压扭转的方法对块体纳米晶Ni-20wt%Fe圆盘进行了严重变形，并用透射电子显微镜对其晶粒长大过程进行了表征。我们的结果提供了可靠的证据表明，对于小于100 nm的颗粒，高压扭转诱导的颗粒长大主要是通过颗粒的旋转来实现的。在晶粒长大过程中，位错主要出现在小角度的亚晶界，长大后在晶内随处可见位错。
Deformation induced grain growth has been widely reported in nanocrystalline materials. However, the grain growth mechanism remains an open question. This study applies high-pressure torsion to severely deform bulk nanocrystalline Ni-20 wt % Fe disks and uses transmission electron microscopy to characterize the grain growth process. Our results provide solid evidence suggesting that high pressure torsion induced grain growth is achieved primarily via grain rotation for grains much smaller than 100 nm. Dislocations are mainly seen at small-angle subgrain boundaries during the grain growth process but are seen everywhere in grains after the grains have grown large.