Crack path and damage in a CuZnAl SMA

Pseudo-elastic (PE) materials are an important class of metallic alloy which exhibit unique features with respect to common engineering metals. In particular, due to these properties PEs are able to recover their original shape after high values of mechanical deformations, by removing the mechanical load (PE). From the microstructural point of view shape memory and pseudo-elastic effects are due to a reversible solid state microstructural diffusionless transitions from austenite to martensite, which can be activated by mechanical and/or thermal loads. Copper-based shape memory alloys are preferred for their good memory properties and low cost of production. In this work the main crack initiation and its propagation in a tensile test is analyzed in order to evaluate crack path and its behavior at low and at high values of deformation. Results are also associated both to grains boundary chemical properties and to X-ray diffraction, in order to correlate structural transition involved in an Cu-Zn-Al alloy characterized by a PE behavior.