Cryogenic rolling induces quasi-linear superelasticity with high strength over a wide temperature range in TiNi shape memory alloys

Abstract

Materials with high functional and strength performance are finding wide range of applications. In this study, we propose an approach to enhance the synergistic relationship between recoverable strain and strength in TiNi shape memory alloys (SMAs) by utilizing cryogenic rolling. Comparative analysis of the rolled samples, which experienced a thickness reduction of up to 13% at a nitrogen temperature, revealed good cycling stability, greater recoverable strain, reduced modulus, and increased strength at room temperature when compared to their undeformed counterparts. Notably, these rolled samples exhibited a significant recoverable strain (>4%) and impressive strength (0.8∼1.6 GPa) over a wide temperature range (∼400 K). Our findings suggest that these enhancements can be attributed to the emergence of the B19′ strain glass transition. This research not only illuminates the potential advantages of cryogenic rolling in shaping the functional and structural properties of SMAs but also offers a promising avenue for effectively regulating properties.