Strain mapping at propagating interfaces in pseudoelastic NiTi
Strain mapping at propagating interfaces in pseudoelastic NiTi
复制标题
伪弹性 NiTi 传播界面处的应变映射
DOI：
10.1051/esomat/200906031
复制
发表时间：
2009
影响因子：
3.8
通讯作者：
M. Wagner
中科院分区：
文献类型：
--
作者：
A. Schaefer;M. Wagner
伪弹性NiTi通常表现出不均匀的马氏体相变：马氏体带通过试样传播，不同的相界面将转化区域与未转化区域分开，并且局部应变在这些界面上呈阶梯状但平滑地增加约5%。在本研究中，我们使用先进的应变映射方法（数字图像相关）来表征局部应变状态和应变率在传播相界面薄NiTi带。由此产生的应变数据允许详细分析的接口几何形状。窄过渡区的特征在于4-5 mm的有限宽度，其通常在试样的外边缘附近增加。此外，在界面处的最大局部应变率是一个数量级高于宏观应变率，通常用于表征热机械加载条件。
Pseudoelastic NiTi often exhibits an inhomogeneous martensitic phase transformation: Martensite bands propagate through the specimen, distinct phase interfaces separate transformed from untransformed regions, and local strains increase step-like but smoothly by ~5 % across these interfaces. In the present study, we use an advanced strain mapping method (digital image correlation) to characterize local strain states and strain rates at propagating phase interfaces in a thin NiTi ribbon. The resulting strain data allows a detailed analysis of the interface geometry. The narrow transition regions are characterized by a finite width of 4-5 mm which generally increases near the outer edges of the specimen. Furthermore, the maximum local strain rates at the interfaces are one order of magnitude higher than the macroscopic strain rate that is usually used to characterize thermo-mechanical loading conditions.