Deforming Nanocrystalline Metals: New Insights, New Puzzles
Deforming Nanocrystalline Metals: New Insights, New Puzzles
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DOI：
10.1002/adem.200400211
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发表时间：
2005-04
影响因子：
3.6
通讯作者：
J. Weissmüller;J. Markmann
中科院分区：
文献类型：
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作者：
J. Weissmüller;J. Markmann
最近的实验为纳米晶金属的塑性机制带来了新的见解。特别是，新的机会已经出现的发现，大块纳米晶体样品具有非常小的晶粒尺寸，制备的惰性气体冷凝技术，可以变形到大的真应变。研究结果阐明了蠕变，部分位错活动沿着及其后果，断层和孪生，以及晶界滑动和晶粒旋转的作用。然而，他们也提出了有趣的新问题，特别是在晶界位错成核的机制，并在孪晶晶粒的滑移系选择和对齐。一个新兴的见解是，在小晶粒尺寸没有“的”变形机制;相反，变形机制地图，例如，由应变速率和晶粒尺寸跨越的参数空间，是更合适的各种过程的表示，控制材料的行为。
Recent experiments have brought new insights into the mechanisms which govern the plasticity of nanocrystalline metals. In particular, new opportunities have arisen from the finding that bulk nanocrystalline samples with extremely small grain size, prepared by the inert gas condensation technique, can be deformed to large true strain. The findings elucidate the roles of creep, partial dislocation activity along with its consequences, faulting and twinning, as well as grain boundary sliding and grain rotation. However, they also rise intriguing new questions, specifically with respect to the mechanisms of dislocation nucleation at grain boundaries, and with respect to slip system selection and alignment in twinned grains. An emerging insight is that there is not ‘the’ deformation mechanism at small grain size; instead, deformation mechanism maps in, for instance, the parameter space spanned by the strain rate and the grain size, are more appropriate representations of the various processes that control the materials behavior.