Mechanical Properties of Ti–50(Pt,Ir) High-Temperature Shape Memory Alloys

To develop high-temperature shape memory alloys, Ti–50(Pt,Ir)mol% compounds are noted because of their martensitic transformation from B2 to B19(2H) or 4H (4O) structures above 1273 K. A thermal expansion measurement and loading-unloading compression test were performed for Ti–50(Pt,Ir) to determine if the shape memory effect or superelasticity was shown. The thermal expansion measurement indicated the shape recovery in some of the compounds. The maximum shape recovery was about 4% by reheating at the above martensite transformation temperature after a loading-unloading compression test. Superelasticity was also observed in ternary compounds. The potential of Ti–50(Pt,Ir) as a high-temperature shape memory alloy is discussed.