Compressive behavior of 64% porosity NiTi alloy: An experimental study

An experimental investigation of the compressive behavior of 64% porosity NiTi alloy was undertaken in this study. Both quasi-static and low-frequency fatigue compressive tests were carried out to obtain the compressive stress–strain curves of specimens. Special attention was paid to the loading–unloading history effect on the stress–strain curves. Full-field surface deformation measurement was carried out via moiré interferometry when specimens were compressed. Inhomogeneous deformation property of the material caused by the porous structure was clearly presented. The loading–unloading history effect was also studied using the moiré interferometry method. Finally real time metallographic analysis during compression tests explained the causes of the loading–unloading history effect of the porous material from microscopic point of view. These findings are believed to be essential elements in the theoretical modeling of compressive behavior especially loading–unloading history effect of the high porosity NiTi alloy, and which still need further systematic examination in the future.