Short communication Effects of tantalum addition on transformation behaviour of (Ni 51 Ti 49 ) 1-x Ta x and Ni 50 Ti 50-y Ta y shape memory alloys

Abstract

The effect of Ta content on the transformation characteristics of Ni–Ti–Ta ternary alloys has been studied. In (Ni₅₁ Ti₄₉)_1-x Ta_x type alloys, the phase transformation temperatures increase with Ta content, especially when the Ta content is less than 4 at.-%. In Ni₅₀ Ti_50-x Ta_x type alloys, the phase transformation temperatures decrease as Ta content increases. The martensite start temperature is less sensitive to changes in Ni content in ternary Ni–Ti–Ta alloys than that in Ni–Ti binary alloys. The phase transformation temperatures of Ni–Ti–Ta ternary alloys are mainly controlled by the Ni/Ti ratio in the Ni–Ti matrix.