Influence of strain rate on superelastic behaviour of TiNi shape memory alloy

The influence of the strain rate on the superelastic behaviour associated with the martensitic transformation is investigated by tensile tests for TiNi shape memory alloy. The results are summarized as follows. The increase in the temperature due to the stress-induced martensitic transformation measured by a non-contact method is an order of magnitude larger than that measured through a thermocouple. The increase in the transformation stress associated with an increase in the strain rate appears to be due to the temperature rise. The superelastic behaviour depending on the strain rate is well expressed by the proposed constitutive equation considering the temperature variation. The proposed equation is useful for the design of superelastic elements.