Macroscopic shape change of Cu13Zn15Al shape memory alloy on successive heating

The shape change of Cu-13Zn-15Al shape memory alloy on successive heating at a heating rate of 5 °C/min has been studied. The behavior of shape change is strongly temperature dependent. As the heating temperature is below 320 °C, the stabilization phenomenon of the martensite appears, and the first reverse shape memory effect (FRSME) in the Cu-13Zn-15Al alloy occurs due to the martensitic nature transformation that involved in the martensite stabilization process. At the temperature between 320 and 400 °C, the forward shape memory effect (FSME) can be caused by the reverse transformation of the stabilized martensite. The second reverse shape memory effect (SRSME) in the Cu-13Zn-15Al alloy occurs when the ribbon is heated to above 450 °C and subsequently air-cooled to room temperature, this phenomenon attributes to the growth of an asymmetric martensite phase due to the constraining of α-phases distributed along the boundary of the new-formed martensite variants.