Martensitic transformation and shape memory effect in Ni₃Ta: A novel high-temperature shape memory alloy

This paper is dedicated to the first observations of the martensitic transformation (MT) and shape memory effect in Ni₃Ta intermetallic compound. It was found that Ni₃Ta undergoes MT with 50 K temperature hysteresis at elevated temperatures (Ms = 530 K, Mf = 500 K, As = 550 K, Af = 580 K). Thermal cycling over the temperature interval of MT does not affect MT temperatures except for a slight shift of the reverse MT temperatures during the first cycle. The crystal structure parameters of the austenite and martensite are determined. The volume change during forward MT deduced from the austenite and martensite lattice parameters relation is -0.45%. The shape recovery after 10% compression at room temperature is almost complete although it takes place in a wide temperature interval-about 300 K. This alloy might open new perspectives for the application of high-temperature shape memory alloys (HTSMA).