Stability of thermal cycling and high temperature mechanical properties for Ti-V-Al-B lightweight shape memory alloy

The microstructure of the Ti-V-Al shape memory alloy with refined grain and in-situ TiB phase was modified by doping minor Boron (B), which contributes to the superior mechanical performances and strain recovery characteristics. Compared with other quaternary Ti-V-Al-X alloys, the Ti-V-Al-B alloy showed the largest ultimate tensile stress due to the solution strengthening, grain refinement and precipitation strengthening of in-situ TiB phase. Moreover, the Ti-V-Al alloy added 0.1 at.%13 possessed the maximum yield stress of 701 MPa and the largest tensile fracture strain of 27.6% at the temperature of 150 degrees C. Meanwhile, the excellent strain recovery characteristics with fully recoverable strain of 4% could be obtained due to B addition. Besides, B addition suppressed the precipitation of omega phase during thermal cycling and further improved the thermal cycling stability of the Ti-V-Al alloy.

Automated summary

The microstructure of the Ti-V-Al shape memory alloy was improved by doping minor Boron (B), resulting in enhanced mechanical performance, strain recovery characteristics, and thermal cycling stability. The addition of Boron contributed to the solution strengthening, grain refinement, and precipitation strengthening of in-situ TiB phase, leading to the highest ultimate tensile stress and largest tensile fracture strain. Moreover, the alloy exhibited excellent strain recovery with fully recoverable strain, and the precipitation of omega phase during thermal cycling was suppressed.