Strain Localization in NiTi Single Crystals

Christos Efstathiou, Prof. Huseyin Sehitoglu

In this investigation we are utilizing full-field strain measurements obtained with digital image correlation (DIC) to understand the transformation behavior of different crystallographic orientations. The advantage of using DIC for characterizing the pseudoelastic response is that the evolution of the transformation interfaces, and the transformation uniformity become obvious in each strain field (see Figure 1).


Shown above is the nominal stress-strain curve, and the evolution of the local strain fields for a single crystal NiTi sample. The green regions indicate material that has transformed whereas the blue region (<1% strain) is untransformed. Note the color bar indicates strain from 0-8%.