High temperature shape memory behavior of Ni50.3Ti25Hf24.7 single crystals

In this work we present the high temperature functional behavior of the new Ni50.3Ti25Hf24.7 shape memory alloy (SMA). Very high transformation strains were measured during isobaric experiments at temperatures up to Af = 420 °C. For the [111]B2 orientation in tension, we measured with digital image correlation (DIC) averaged transformation strain of 5.15%, while in small domains 7.74%. For the [011]B2 orientation in compression, we measured averaged transformation strain of 4.6%, locally 5.3%. The remarkable results in terms of actuation strains at T > 400 °C define the Ni50.3Ti25Hf24.7 alloy as one of the most promising shape SMA for high temperature applications.