The influence of sintering parameters in the microstructure and mechanical properties of a Cu-Al-Ni-Mn-Zr shape memory alloy

Abstract

Shape memory alloys from the Cu–Al–Ni system arouse interest for industrial applications due to their high thermal stability and low cost. In this study, the Cu–11.8Al–3.2Ni–3Mn–0.5Zr alloy is prepared through a powder metallurgy processing technique. Specimens are produced by a conventional uniaxial press followed by sintering procedure under argon atmosphere. The sintering temperature is varied in the range from 950 to 1060 °C, whereas sintering time is varied from 0.5 to 2 h. The results denote that a temperature close to the alloy's solidus temperature is necessary to achieve higher densities. Moreover, martensite‐type microstructures are observed, despite the slow cooling rate applied after sintering. The compression strengths are in the order of 500 MPa with the exception of the specimens sintered for 1.5 h, which reaches an average of 700 MPa. This is explained by the lower porosity resulting from liquid phase sintering. The forward and reverse martensitic transformation temperatures, however, are quite similar for all examined conditions