HIGH TRANSFORMATION TEMPERATURE SHAPE MEMORY ALLOY

A high temperature titanium-based shape memory alloy contains from at least 0.1 at. % hafnium. Articles formed from the disclosed alloy have high transformation temperatures. The alloy of the invention can be successfully hot and cold worked to make articles such as springs and wires. Preferred alloys for making such articles according to the invention consist essentially of compositions of the general formula: MATi(100-A-B)XB wherein M is a metal other than zirconium and hafnium, preferably Ni, A is 30 to 51 at. %, B is 0.1 to 50 at %, and X is Hf or a combination of Hf and Zr, provided that: (a) the amount of Zr does not exceed about 25 at. % in the alloy; (b) the amount of Hf is at least 0.1 at. %; and (c) the sum of A + B is 80 at. % or less.