Uniaxial mechanical response of polycrystalline shape memory alloys

Abstract

Shape memory alloys (SMA) are materials that can remember their original shapes. Even if they are subjected to high deformations, they can return back to their original shapes when loading is removed. Their deformation mechanism is based on martensitic phase transformations (PT). In this study, uniaxial material response of polycrystalline SMA is inspected using finite element (FE) method. The material model developed by Levitas and Ozsoy (2009) is used and stress-strain diagrams and volume fractions of austenite and martensite during external loading are determined. The results are found to be in agreement with the experimental results. Moreover, increase in athermal friction, which prevents the interface propagation, delays the PT and for different friction values, different hysteresis is obtained. It is also shown that material response determined by experiments can be obtained using this model. © (2013) Trans Tech Publications, Switzerland.