Length-scale-dependent deformation mechanisms in incoherent metallic multilayered composites
Length-scale-dependent deformation mechanisms in incoherent metallic multilayered composites
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DOI：
10.1016/j.actamat.2005.06.025
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发表时间：
2005-10-01
期刊：
影响因子：
9.4
通讯作者：
Hoagland, RG
中科院分区：
文献类型：
--
作者：
Misra, A;Hirth, JP;Hoagland, RG
测量了Cu-Nb多层膜的纳米压痕硬度与双层膜周期的关系。对于这个面心立方/体心立方系统与非相干界面，我们开发的多层流动强度的位错模型作为长度尺度的函数从大于一微米到小于一纳米。基于位错堆积的Hall-Petch模型被发现适用于亚微米的长度尺度和Hall-Petch斜率被用来估计的多层膜的峰值强度。在几个到几十个纳米的长度尺度上，单位错的限制层滑移被视为操作机制。该模型考虑了位错核沿界面沿着扩展、界面应力和界面位错排列对约束层滑移应力的影响，能正确预测强度随层厚减小而增加的规律。在几纳米或更小的层厚度处，强度达到峰值。我们假设，这个峰值强度设置的界面阻力单位错传输，并计算从限制层滑移的界面切割机制的过渡。(c)2005 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Nano-indentation hardness as a function of bilayer period has been measured for sputter-deposited Cu-Nb multilayers. For this face-centered cubic/body-centered cubic system with incoherent interfaces, we develop dislocation models for the multilayer flow strength as a function of length scale from greater than a micrometer to less than a nanometer. A dislocation pile-up-based Hall-Petch model is found applicable at the sub-micrometer length scales and the Hall-Petch slope is used to estimate the peak strength of the multilayers. At the few to a few tens of nanometers length scales, confined layer slip of single dislocations is treated as the operative mechanism. The effects of dislocation core spreading along the interface, interface stress and interface dislocation arrays on the confined layer slip stress are incorporated in the model to correctly predict the strength increase with decreasing layer thickness. At layer thicknesses of a few nanometers or less, the strength reaches a peak. We postulate that this peak strength is set by the interface resistance to single dislocation transmission, and calculate the transition from confined layer slip to an interface cutting mechanism. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.