Engineering Considerations in the Application of NiTiHf and NiAI as Practical High-Temperature Shape Memory Alloys

Abstract

AbstractNiTiHf and NiAI have shown the potential for development as high temperature shape memory alloys with transformation temperatures of 150°C or higher. However, various engineering considerations must be addressed before these systems can be used as practical high temperature shape memory alloys. These considerations include: fabricability, phase stability, mechanical stability, and cost. NiTiHf is attractive from a cost standpoint, although its fabricability must still be demonstrated on larger heats of material. The phase stability and mechanical stability of NiTiHf are unknown. NiAl requires great improvements in both fabricability and phase stability. The mechanical stability and costs for producing NiAI shape memory alloys are still unclear.