抄録
To develop high temperature shape memory alloys, TiPt and TiIr are noted because of their possibility of phase transformation above 1273K. Then, the effects of Iridium (Ir) into TiPt on the constituent phases and the phase transformation temperature were investigated. It was found that the B19 phase appeared up to 37.5at% Ir in Ti (Pt, Ir) and the phase transformation temperature raised from 1303K in TiPt to 1473K in the Ti-12.5Pt-37.5Ir. Shape recovery and superelasticity of Ti-50 (Pt, Ir) were investigated by thermal expansion measurement in dilatometer and loading-unloading compression test. The shape recovery was found in all compounds in at least one of the testing methods. The highest shape recovery, about 4% was found in Ti-25Pt-25Ir using loading-unloading compression test. On the other hand, superelasticity was found in only ternary compounds. Larger superelasticity was observed in ternary compounds with higher Ir contents. Potential of Ti-50 (Pt, Ir) as high-temperature shape memory alloys is discussed.
