Effect of thermal annealing on the anelastic properties of the martensitic transformation in Ni–Mn–Sb–Al metamagnetic shape memory alloys

Abstract The influence of thermal treatments on the reverse martensitic transformation (MT) and damping behaviour of Ni 50 Mn 37.5 Sb 10.5 Al 2 and Ni 50 Mn 37.5 Sb 4.5 Al 8 metamagnetic shape memory alloys was investigated. Thermal annealing was performed in situ during mechanical spectroscopy measurements, with the annealing temperature systematically increased to assess its effect on the reverse MT. Recovery and precipitation processes were identified and their influence on the reverse MT analysed. The results reveal a sharpening of the MT, a shift of the MT damping peak temperatures, and an increase in the MT peak height. Different damping mechanisms associated with twin-boundary motion and dislocation–vacancy interactions were identified. Amplitude-dependent damping analysis reveals a characteristic evolution of the S coefficient, reflecting the competition between the transient and non-transient dissipation mechanisms during the transformation.