Untangling dislocation and grain boundary mediated plasticity in nanocrystalline nickel
Untangling dislocation and grain boundary mediated plasticity in nanocrystalline nickel
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DOI：
10.1016/j.actamat.2013.10.071
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发表时间：
2014-02-15
期刊：
影响因子：
9.4
通讯作者：
Gruber, Patric A.
中科院分区：
文献类型：
--
作者：
Lohmiller, Jochen;Grewer, Manuel;Gruber, Patric A.
纳米晶（nc）材料具有独特的机械性能，如非常高的强度。然而，对变形机制和变形过程中发生的相关微观过程的连续性的理解仍然是不完整的。我们利用同步加速器原位压缩实验来研究晶粒尺寸为30 nm的块体纳米镍的变形机制。这项研究是伴随着高分辨率的晶粒尺寸分析和晶体取向映射使用透射电子显微镜。无论初始的微观结构，电沉积纳米镍的变形行为是由不均匀的弹性晶格应变和它的住宿内的晶界网络，其次是位错塑性的发病，这是从织构演化推断，和应力驱动的晶粒生长。这一观察结果表明，数控金属的变形是由一系列不同的，部分重叠的机制。据估计，晶内位错塑性仅占总变形量的40%左右。(C)2013 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Nanocrystalline (nc) materials possess unique mechanical properties, such as very high strength. However, an understanding of the deformation mechanisms and the succession of related microscopic processes that occur during deformation is still incomplete. We used synchrotron-based in situ compression testing to investigate the sequence of deformation mechanisms emerging in bulk nc nickel with a grain size of 30 nm. The study was accompanied by high-resolution grain size analysis and crystal orientation mapping using transmission electron microscopy. Regardless of the initial microstructure, the deformation behavior of electrodeposited nc Ni is initiated by inhomogeneous elastic lattice straining and its accommodation within the grain boundary network, followed by the onset of dislocation plasticity, which was inferred from texture evolution, and stress-driven grain growth. This observation indicates that deformation in nc metals is governed by a succession of different, partly overlapping mechanisms. It is estimated that intragranular dislocation plasticity contributes only about 40% to the overall deformation. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.