An in situ TEM study of the size effect on the thermally induced martensitic transformation in nanoscale NiTi shape memory alloy
An in situ TEM study of the size effect on the thermally induced martensitic transformation in nanoscale NiTi shape memory alloy
复制标题
原位 TEM 研究纳米 NiTi 形状记忆合金热致马氏体转变的尺寸效应
DOI：
10.1016/j.jallcom.2013.11.119
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发表时间：
2014-03-05
影响因子：
6.2
通讯作者：
Yin, X. Q.
中科院分区：
文献类型：
--
作者：
Li, H. X.;Mao, S. C.;Yin, X. Q.
这项原位 TEM 研究调查了样品厚度对 NiTi 马氏体转变的影响。随着样品厚度的减小，转变温度逐渐降低。当厚度低于临界值时没有观察到转变。对于所研究的 Ti-50.8 at.%Ni 合金，R 相和马氏体转变的临界厚度值分别确定为类似于 22 nm 和类似于 50 nm。这种明显的“尺寸效应”归因于表面氧化导致基体中钛的消耗，这一点通过氧含量测量得到了证实。这些发现表明，在使用镍钛制造微机电器件时必须考虑自然氧化及其对转变温度的影响。 (C) 2013 Elsevier B.V. 保留所有权利。
This in situ TEM study investigated the effect of sample thickness on the martensitic transformation of NiTi. The transformation temperature gradually decreased with decreasing sample thickness. No transformation was observed when the thickness was below a critical value. The critical thickness values for the R phase and martensitic transformations were determined to be similar to 22 nm and similar to 50 nm, respectively, for the Ti-50.8 at.%Ni alloy studied. This apparent "size effect" was attributed to the depletion of Ti in the matrix caused by surface oxidation, as confirmed by oxygen content measurements. These findings demonstrate that natural oxidation and its influence on the transformation temperature must be taken into consideration in the fabrication of micro-electro-mechanical devices using NiTi. (C) 2013 Elsevier B. V. All rights reserved.