Correlations between dislocation density evolution and spall strengths of Cu/Ta multilayered systems at the atomic scales: The role of spacing of KS interfaces
Correlations between dislocation density evolution and spall strengths of Cu/Ta multilayered systems at the atomic scales: The role of spacing of KS interfaces
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DOI：
10.1016/j.mtla.2018.100192
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发表时间：
2019-03-01
期刊：
影响因子：
3.4
通讯作者：
Dongare, A. M.
中科院分区：
文献类型：
--
作者：
Chen, J.;Mathaudhu, S. N.;Dongare, A. M.
在冲击载荷条件下，在原子尺度上研究了具有 Kurdjumov-Sachs (KS) 取向关系的 Cu/Ta 多层系统的变形和失效（散裂）行为。分子动力学 (MD) 模拟研究了 KS 界面之间的间距对层厚度范围为 3 nm 至 47 nm 的 Cu/Ta 多层微结构中缺陷结构（位错）的成核、演化和相互作用的作用。分别使用 Hugoniot 弹性极限 (HEL) 和剥落强度的计算值来研究冲击压缩响应和失效响应。 KS 界面充当位错在界面上传播和传输的强大屏障，并且观察到界面的间距会影响剥落行为。剥落强度值的变化表明临界界面间距为 6 nm，低于该间距，观察到多层微结构的剥落强度低于相同负载条件下单晶铜的剥落强度。各种微观结构的剥落平面处各种类型位错的密度随时间的演变与剥落强度的结果值之间的相关性为为什么微观结构导致多相系统的剥落强度值增加/减少提供了清晰的原理。
The deformation and failure (spallation) behavior of Cu/Ta multilayered systems with Kurdjumov-Sachs (KS) orientation relationship is investigated at the atomic scales under shock loading conditions. Molecular dynamics (MD) simulations investigate the role of spacing between KS interfaces on the nucleation, evolution and interaction of defect structures (dislocations) in the Cu/Ta multilayered microstructures with layer thicknesses ranging from 3 nm to 47 nm. The shock compression response and failure response is investigated using the computed values of the Hugoniot elastic limit (HEL) and the spall strengths, respectively. KS interfaces serve as strong barriers to dislocation propagation and transmission across the interface and the spacing of the interfaces is observed to influence the spall behavior. The variation of the spall strength values suggests a critical interface spacing of 6 nm, below which the spall strength of the multilayered microstructure is observed to be lower than that for single-crystal Cu for the same loading conditions. The correlations between the temporal evolution of densities of various types of dislocation at the spall planes for the various microstructures and the resulting values of the spall strengths provide a clear rationale for why a microstructure results in increased/decreased spall strength values for the multiphase system.