Synergistic effect of TiN ceramic particle and grain refinement in enhancing the higher performance Ti–V–Al based shape memory alloy

Abstract

In the present study, in-situ TiN ceramic particles were introduced into Ti–V–Al based shape memory alloys to optimize mechanical properties and friction resistance. The results revealed that increasing the TiN content resulted in the transition from α" to β phase, and led to a reduction in the martensitic transformation temperature. Additionally, the TiN ceramic particles were found to significantly reduced the grain size of the Ti–V–Al based shape memory alloys. Compared to other Ti–V–Al-X shape memory alloys, the introduction of TiN ceramic particles enhanced the mechanical and wear properties of the Ti–V–Al shape memory alloy. These improvements can be attributed to a combination of solid solution strengthening, grain refinement and precipitation strengthening. Notably, the (Ti–V–Al)100-xNx shape memory alloy exhibited a maximum yield strength of 568 MPa and a fracture strength of 788 MPa. Furthermore, the micro-hardness of the Ti–V–Al based shape memory alloy increased monotonously from 355HV to 393HV, while the wear coefficient steadily decreased from 0.53 to 0.48. In conclusion, by adjusting content of TiN ceramic particles, it is possible to obtain a lightweight Ti–V–Al shape memory alloy with tailored martensitic transformation temperatures, enhanced strength and hardness, as well as excellent friction properties.