Abstract 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.

中文翻译：

---

通过离散滑移晶体塑性模型预测纳米层材料强度的尺寸缩放

摘要 金属纳米层复合材料 (MNCs) 的主要吸引力不仅在于它们的强度比其成分增加了 5 到 10 倍，而且还在于它们的优越强度与纳米层厚度的可调性。虽然强度的尺寸缩放在许多 MNC 材料系统中普遍存在，但无法使用晶体塑性框架准确预测尺寸缩放。在这里，我们提出了一种基于晶体塑性的计算方法，该方法认为塑性发生在晶界控制的离散滑移事件中，并将其应用于预测 Cu/Nb MNC 的变形响应和潜在机制。显示预测的拉伸应力 - 应变响应与四种不同纳米层厚度的测量结果一致，而不引入可调节参数。该模型预测了层厚度上强度的 Hall-Petch 尺寸缩放以及随着层厚度减小而上升的塑性各向异性。结果分析表明，层尺寸对强度的影响源于层厚度的限制位于晶界中位错源的长度。