Evaluation of Cu-26Zn-5Al shape memory alloy fabricated by accumulative roll bonding process

Abstract

Cu/Zn/Al multilayered composites consisting of pure copper, zinc, and aluminum were produced by accumulative roll bonding. Afterwards, heat treatment processes at various temperatures (750, 825, and 900 °C) were followed on the prepared composites to fabricate Cu-Zn-Al shape memory alloys. The prepared samples were characterized by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and X-ray diffraction. Mechanical properties of the composites and alloys were also investigated by hardness and tensile tests. The shape memory effect of the prepared alloys was evaluated by bending tests and subsequent heating. The results presented that the fabricated composite has a homogeneous distribution of Zn and Al layers in the Cu matrix. It was also found that the alloys treated at 750 and 825 °C consist of α and martensite phases, whereas only 18R martensite is formed in the alloy fabricated at 900 °C. Additionally, the alloy annealed at 900 °C exhibited a good strength (about 500 MPa), ductility (about 22%) and shape memory effect. It was concluded that Cu-Zn-Al shape memory alloys can be successfully fabricated by accumulative roll bonding and subsequent heating treatment processes.