Determining transformation temperatures of equiatomic TiNi shape memory alloy by dynamic mechanical analysis test

Abstract

Abstract Strain variation induced by martensitic transformation of Ti 50 Ni 50 shape memory alloy (SMA) is investigated by dynamic mechanical analysis (DMA) test. The extent of the positive and negative strain variation is mainly associated with the softening and hardening rate of storage modulus E 0 , respectively. The occurrence of the strain variation is related to DMA instrument design since the stress accommodation cannot keep up with the drastic change of the E 0 softening/hardening rate during transformation. Strain variation is very sensitive and can rapidly respond to the E 0 change, thus martensitic transformation temperatures of SMAs associated with a multi-stage transformation can be determined precisely from the onset/finish of the strain variation.