Effect of Severe Plastic Deformation on Shape Memory and Mechanical Properties of Nanostructured Cu-Zn-Al Alloy

Abstract

Characterization and mechanical behavior was investigated on Cu-Zn-Al shape memory alloy subjected to severe plastic deformation by equal channel angular pressing (ECAP). The microstructure, phase transformation temperatures and morophological features were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC) and optical microscope (OM). Homogenous microstructure and grain refinement, which leads to improvement of mechanical properties, was readily achieved by severe plastic deformation (SPD). The XRD results showedtransformation happened from α-phase to martensite phase which induced by the mechanical activated transformation process that has also resulted in the increase of martensite start temperature (MS) after the ECAP process. The alloy’s Vickers hardness increased rapidly from 136 to 217 through the first pass at 400 °C, and then it increased slowly and tended to be stable with increasing of ECAP passes. The yield and compressive strength of specimens increased 242 % and 29 % after ECAP process.