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在纳米晶中以粒度边界为媒介的可塑性

Zhiwei Shan¹, E A Stach, J M K Wiezorek

¹Department of Mechanical Engineering, University of Pittsburgh, 648 Benedum Hall, Pittsburgh, PA 15261, USA.

Science (New York, N.Y.)

|August 3, 2004

概括

纳米晶 (10纳米颗粒) 的变形转移到颗粒边界过程中. 这是由于随着颗粒大小的减少,脱位运动和扩散辅助的颗粒边界机制之间的竞争造成的.

科学领域:

材料科学材料科学材料科学
纳米技术纳米技术
固体力学固体力学是什么

背景情况:

晶体材料中的塑性变形主要由晶格脱位核和运动控制.
了解纳米晶体材料的变形机制对于它们的应用至关重要.

研究的目的:

在纳米尺度上研究纳米晶薄膜的变形机制.
阐明颗粒边界在具有较小颗粒大小的材料的塑性行为中的作用.

主要方法:

在现场使用动态传输电子显微镜 (DTEM).
对纳米晶薄膜进行了观察,平均颗粒大小约为10纳米.

主要成果:

在10nm膜中,以粒度边界为媒介的过程被确定为主要的变形模式.
观察到格子脱位在变形后被困在个体粒中.
观察到变形机制的转变,受粒径的大小的影响.

结论:

观察到的变形模式的变化归因于基于脱位和基于谷物边界的过程之间的竞争.
扩散辅助的谷物边界机制在控制塑料行为方面变得重要,因为谷物大小减少.
纳米级的颗粒大小从根本上改变了晶体材料中的塑性变形路径.

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