Revealing ultralarge and localized elastic lattice strains in Nb nanowires embedded in NiTi matrix.
Revealing ultralarge and localized elastic lattice strains in Nb nanowires embedded in NiTi matrix.
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揭示嵌入 NiTi 基体中的 Nb 纳米线的超大局部弹性晶格应变
DOI：
10.1038/srep17530
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发表时间：
2015-12-02
影响因子：
4.6
通讯作者：
Cui L
中科院分区：
文献类型：
--
作者：
Zang K;Mao S;Cai J;Liu Y;Li H;Hao S;Jiang D;Cui L
已经发现独立式纳米线表现出超大的弹性应变（4至7%）和超高强度，但是已经证明难以以块状形式利用其固有的上级机械性能。最近的一项研究表明，在晶格应变匹配的原则下，在嵌入NiTi基体中的Nb纳米线中可以实现~6%的超大弹性应变。为了验证这一假设，本研究研究的弹性变形行为的Nb纳米线嵌入在NiTi基体通过原位透射电子显微镜测量拉伸变形过程中。实验工作表明，高达8%的超大的局部弹性晶格应变诱导在Nb纳米线的应力诱导马氏体域在NiTi基体中的相邻区域，而其他部分的纳米线表现出大大减少的晶格应变时，在NiTi基体中的未转变的奥氏体相邻。这些观察结果提供了晶格应变匹配的建议机制的直接证据，从而一种新的方法来设计纳米复合材料的上级机械性能。
Freestanding nanowires have been found to exhibit ultra-large elastic strains (4 to 7%) and ultra-high strengths, but exploiting their intrinsic superior mechanical properties in bulk forms has proven to be difficult. A recent study has demonstrated that ultra-large elastic strains of ~6% can be achieved in Nb nanowires embedded in a NiTi matrix, on the principle of lattice strain matching. To verify this hypothesis, this study investigated the elastic deformation behavior of a Nb nanowire embedded in NiTi matrix by means of in situ transmission electron microscopic measurement during tensile deformation. The experimental work revealed that ultra-large local elastic lattice strains of up to 8% are induced in the Nb nanowire in regions adjacent to stress-induced martensite domains in the NiTi matrix, whilst other parts of the nanowires exhibit much reduced lattice strains when adjacent to the untransformed austenite in the NiTi matrix. These observations provide a direct evidence of the proposed mechanism of lattice strain matching, thus a novel approach to designing nanocomposites of superior mechanical properties.