Predicting the size scaling in strength of nanolayered materials by a discrete slip crystal plasticity model
Predicting the size scaling in strength of nanolayered materials by a discrete slip crystal plasticity model
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DOI：
10.1016/j.ijplas.2019.08.016
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发表时间：
2020-01-01
影响因子：
9.8
通讯作者：
Zhou, Caizhi
中科院分区：
文献类型：
--
作者：
Chen, Tianju;Yuan, Rui;Zhou, Caizhi
金属纳米层复合材料的主要吸引力不仅在于其强度比其组分增加五到十倍，而且还在于其上级强度与纳米层厚度的可调谐性。虽然在许多MNC材料系统中普遍存在强度的尺寸缩放，但是不能用晶体塑性框架准确地预测尺寸缩放。在这里，我们提出了一个晶体塑性为基础的计算方法，认为塑性发生在晶粒边界控制的离散滑移事件，并将其应用于预测Cu/Nb MNCs的变形响应和潜在的机制。预测的拉伸应力-应变响应，以实现协议与测量四个不同的纳米层厚度，而不引入可调参数。该模型预测的Hall-Petch尺寸缩放层厚度的强度和上升的塑性各向异性作为层厚度减少。分析结果表明，层厚对强度影响的根源在于层厚对位错源长度的限制。
The main attraction of metallic nanolayered composites (MNCs) lies not only with their five-to ten-fold increases in strength over that of their constituents, but also in the tunability of their superior strength with nanolayer thickness. While the size scaling in strength prevails in many MNC material systems, the size scaling cannot be accurately predicted with crystal plasticity framework. Here, we present a crystal plasticity based computational method that considers plasticity to occur in grain boundary-controlled discrete slip events and apply it to predict the deformation response and underlying mechanisms in Cu/Nb MNCs. Predicted tensile stress-strain responses are shown to achieve agreement with measurements for four distinct nanolayer thicknesses, without introducing adjustable parameters. The model predicts the Hall-Petch size scaling of strength on layer thickness and the rising plastic anisotropy as the layer thickness reduces. Analysis of the results indicates that the origin of the layer size effect on strength results from the limits layer thickness places on the lengths of dislocations sources lying in the grain boundaries.