Effects of Annealing on Microstructure and Phase Transformation Temperature of NiTiNb Shape Memory Alloy after Equal Channel Angular Pressing

摘要

The effect of annealing temperature ( 300-600°C ) on the microstructure and transformation temperature of NiTiNb shape memory alloy rods deformed with equal channel angular pressing (ECAP) method was analyzed. The results show that the hard brittle phase (Ti,Nb) _2Ni was decreased after ECAP. With the rising of annealing temperature, the number of P-Nb phase increase while eutectic declines. The DSC analysis shows that the martensite and reverse transformation temperature increase with annealing temperature. After annealing with 500°C, the martensite/austenite transformation starting temperatures rise to -64.6°C and -30.°C, respectively.