Cyclic loading effects on NITI alloys under biaxial conditions

Abstract

In this work, the influence of the direction and the history of thermomechanical loading of NiTi shape memory alloys on the overall material behavior is experimentally investigated. In the first part, cyclic biaxial mechanical loading has been applied to cross-shaped specimens under constant temperature. The residual strains of selected points from the sample surface are extracted and analyzed. The second part of the study concerns thermomechanical testing of textured samples cut from a laminated plate under complex cyclic loading at different temperature levels. The evolution of residual strains and the transformation threshold are correlated to the history of loading and the amplitude of transformation strain. Anisotropic effects are studied by performing those same experiments on different directions according to the rolling direction of the laminated plate.