Role of interface-affected dislocation motion on the strength of Mg/Nb nanolayered composites inferred by dual-mode confined layer slip crystal plasticity
Role of interface-affected dislocation motion on the strength of Mg/Nb nanolayered composites inferred by dual-mode confined layer slip crystal plasticity
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DOI：
10.1016/j.jmps.2021.104421
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发表时间：
2021-04-08
影响因子：
5.3
通讯作者：
Beyerlein, Irene J.
中科院分区：
文献类型：
--
作者：
Wang, Jiaxiang;Knezevic, Marko;Beyerlein, Irene J.
在这项工作中，我们提出了一种纳米敏感的晶体可塑性模型，用于纳米胶质酸酯复合材料的变形响应。该模型用于研究Mg/Nb纳米复合材料的强度，其中Mg相具有六角形的封闭式包装（HCP）或身体中心（BCC）的晶体结构。为了明确考虑层厚度和双相界面对晶体学滑移的影响，该模型具有强化定律，称为双模式限制层滑移（CLS）。该模型应用于对MG/NB纳米复合材料进行的应力应变测量套件，不同的层厚度，纹理和界面结构。实验表明，BCC/BCC MG/NB纳米复合材料的强度大大高于HCP/BCC纳米复合材料。除了较细的层厚度外，该模型表明，与HCP MG中的（a）滑动模式相比，假构型BCC毫克相可以提高（111）滑动模式的滑动强度。这也表明，相干界面比不一致的界面具有较小的脱位运动阻力。因此，发现BCC/BCC复合强度从降低的层厚度和其BCC相的较高固有强度所施加的位错运动的限制中受益，但是如果界面不是尖锐的相干界面，则会更高。
In this work, we present a nanostructure-sensitive crystal plasticity model for the deformation response of nanolaminate composites. The model is applied to investigate the strength of Mg/Nb nanocomposites, wherein the Mg phase has either a hexagonal close-packed (HCP) or a bodycentered cubic (BCC) crystal structure. To account explicitly for the effects of layer thickness and biphase interface on crystallographic slip, the model features a hardening law, called dualmode confined layer slip (CLS). The model is applied to a suite of stress-strain measurements made on Mg/Nb nanocomposites, varying layer thickness, texture, and interface structure. Experiments show that the BCC/BCC Mg/Nb nanocomposites achieve substantially higher strength than the HCP/BCC nanocomposites. Apart from the finer layer thicknesses, the model indicates that the pseudomorphic BCC Mg phase contributes to strength by increasing the slip strengths of the (111) slip modes compared to the (a) slip modes in HCP Mg. It also suggests that the coherent interface poses less resistance to dislocation motion than the incoherent interface. It is, therefore, found that the BCC/BCC composite strength benefited from both the confinement on dislocation motion imposed by the reduced layer thickness and higher inherent strength of its BCC phase, but that it would be even higher if the interface was not a sharp coherent interface.