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

Abstract

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.

KEYWORDS:

• Shape memory effect
• two-way shape memory
• high strain rate deformation
• split Hopkinson pressure bar
• stress-induced martensite
• martensite reorientation
• TiNi alloy

Acknowledgements

Research was performed using the Centre for Thermogravimetric and Calorimetric Research, the Interdisciplinary Resource Centre for Nanotechnology of the Research Park of St Petersburg State University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by Russian Science Foundation (project no. 19-79-00131).