Functional behaviour of TiNi shape memory alloy after high strain rate deformation

This paper presents an investigation of the influence of strain rate on the functional behaviour of TiNi alloy. Specimens were deformed in compression and tension modes using the Kolsky method for a split Hopkinson pressure bar, and its modification in martensitic, austenitic, and pre-martensitic states at 500, 1000, and 1500 s(-1) strain rates. One-way shape memory and two-way shape memory (TWSM) effects were measured and compared with ones after quasi-static deformation. With an increase in the strain rate, the one-way shape memory effect decreased, but the TWSM effect increased. Functional behaviour indirectly demonstrated the sensitivity of the martensite reorientation and the formation of stress-induced martensite to strain rate. Strain rate sensitivity led to differences in the shape recovery curves during thermocycling.

Automated summary

This study investigates the impact of strain rate on the functional behavior of TiNi alloy, finding that the one-way shape memory effect decreases with increasing strain rate, while the two-way shape memory effect increases. This indicates the sensitivity of martensite reorientation and strain rate on stress-induced martensite formation, leading to differences in shape recovery curves during thermocycling.