Tensile/compressive behaviour of non-layered tetragonal Ni52.8Mn25.7Ga21.5 alloy

The stress–strain behaviour of the alloy Ni52.8Mn25.7Ga21.5 with the non-modulated tetragonal martensite (T) crystal structure was studied below Ms temperature with stresses needed for the martensite variant structure reorientation, i.e. detwinning. At ambient temperature the stress plateau of the detwinning showed a total strain of 21–22% with 18–20 MPa stress. After the first cycle, the tensile/compression cycles were repeatable. With maximum strain the single variant structure was obtained which was verified with X-ray pole figures. The tension-compression cycling decreased the stress plateau to 10–12 MPa, while the increasing testing temperature lead to a value of 6.7 MPa close to the reverse transformation temperature.