Origin of high strength, low modulus superelasticity in nanowire-shape memory alloy composites.
Origin of high strength, low modulus superelasticity in nanowire-shape memory alloy composites.
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纳米线形状记忆合金复合材料高强度、低模量超弹性的起源
DOI：
10.1038/srep46360
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发表时间：
2017-04-12
影响因子：
4.6
通讯作者：
Sun J
中科院分区：
文献类型：
--
作者：
Zhang X;Zong H;Cui L;Fan X;Ding X;Sun J
一个悬而未决的问题是一个潜在的机制，最近发现的纳米复合材料，它由形状记忆合金（SMA）矩阵嵌入金属纳米线（NW），表现出新的机械性能，如大的准线性弹性应变，低杨氏模量和高屈服强度。我们使用有限元模拟研究SMA基体的超弹性和嵌入式纳米线的弹塑性变形之间的相互作用。我们的研究结果表明，应力传递起着主导作用，在确定的准线性行为的纳米复合材料。相应的显微组织演变表明，这种转移是由于纳米线内的塑性变形和基体中的马氏体相变之间的耦合，即，SMA基体的马氏体相变促进了附近的局部塑性变形，而纳米线的高塑性应变区在周围的SMA基体中保留了大量的马氏体，从而有利于后续加载中的马氏体相变的继续。基于这些发现，我们提出了一个实现准线性弹性的一般标准。
An open question is the underlying mechanisms for a recent discovered nanocomposite, which composed of shape memory alloy (SMA) matrix with embedded metallic nanowires (NWs), demonstrating novel mechanical properties, such as large quasi-linear elastic strain, low Young’s modulus and high yield strength. We use finite element simulations to investigate the interplay between the superelasticity of SMA matrix and the elastic-plastic deformation of embedded NWs. Our results show that stress transfer plays a dominated role in determining the quasi-linear behavior of the nanocomposite. The corresponding microstructure evolution indicate that the transfer is due to the coupling between plastic deformation within the NWs and martensitic transformation in the matrix, i.e., the martensitic transformation of the SMA matrix promotes local plastic deformation nearby, and the high plastic strain region of NWs retains considerable martensite in the surrounding SMA matrix, thus facilitating continues martensitic transformation in subsequent loading. Based on these findings, we propose a general criterion for achieving quasi-linear elasticity.