The Enhanced Shape Memory Effect and Mechanical Properties in Thermomechanically Processed Semi‐Equiatomic NiTi Shape Memory Alloy

Abstract

The hot compression tests in a wide range of temperature were employed to produce the semi‐finished products of equiatomic NiTi shape memory alloy holding enhanced mechanical properties. The precise analyses of the compensated flow curves and the microstructures indicated the occurrence of dynamic recovery at lower temperatures and dynamic recrystallization at higher temperature regime. In addition a significant influence on the critical transformation temperatures was also realized. This could affect the martensite plates’ characteristics and the fraction of retained austenite phase. In consequence the room temperature mechanical properties and shape memory response of the alloy were influenced. In an elaborated optimized TMP scheme, the recovery ratio was increased from ≈30% to ≈80%.