The hardness and related deformation mechanisms in nanoscale crystalline-amorphous multilayers
The hardness and related deformation mechanisms in nanoscale crystalline-amorphous multilayers
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纳米级结晶非晶多层膜的硬度和相关变形机制
DOI：
10.1016/j.tsf.2015.01.067
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发表时间：
2015-06-01
期刊：
影响因子：
2.1
通讯作者：
Xu, K. W.
中科院分区：
文献类型：
--
作者：
Cui, Y.;Huang, P.;Xu, K. W.
最近发现，由于纳米层有限的结构，纳米晶-非晶多层可以同时具有高强度和延展性，因此采用深度传感纳米压痕来评估纳米级晶-Cu/非晶-CuZr (C/A)多层在各种非晶层厚度和恒定晶铜层厚度下的硬度和剪切带变形行为。通过改变非晶层的单层厚度，观察到对C/A多层材料硬度的弱化和强化效应，与混合规则得出的结果相比，其中位错运动的不连续性起着至关重要的作用。确定了 20 nm 的临界非晶层厚度，在该厚度之上，界面位错吸收主导塑性变形，导致弱化效应，在该厚度之下，连续位错阻碍占据主导地位并负责强化效应。还广泛讨论了压痕下观察到的剪切带形态的机制。 (C) 2015 Elsevier B.V. 保留所有权利。
Built upon recent findings that nanocrystalline-amorphous multilayers could possess both high strength and ductility due to nano-layer-limited structures, depth-sensing nanoindentation was employed to evaluate the hardness and shear band deformation behavior of nanoscale crystalline-Cu/amorphous-CuZr (C/A) multilayers among a wide range of amorphous layer thickness with constant crystalline Cu layer thickness. By varying individual layer thickness of amorphous layers, both weakening and strengthening effects on the hardness of C/A multilayers were observed, comparing with that derived from the rule of mixture, for which discontinuity of dislocation motion played a crucial role. A critical amorphous layer thickness of 20 nm was identified, above which interface-dislocation-absorption dominated plastic deformation, causing the weakening effect, below which, continuous-dislocation-impediment took over and was responsible for the strengthening effect. Mechanisms underlying the observed shear band morphologies under indentation were also extendedly discussed. (C) 2015 Elsevier B.V. All rights reserved.