Improvement of Mechanical Behaviour in B doped Ni3Ta based High Temperature Shape Memory Alloy

Shape memory alloys (SMAs) able to exhibit the martensitic transformation (MT) at high temperature (above 100°C) are very attractive smart materials for some industrial sectors, such as automotive and aerospace ones. Their main issues regard the brittleness, limiting their processing, and the unstable functionality upon thermal cycling. In this work, the effect of B addition (0.8% in atomic percentage) in the place of Ni and Ta in Ni3Ta SMA on the MT, microstructure and mechanical properties is studied. It is found that the MT occurs above 200°C and its thermal stability can be reached after few thermal cycles. The addition of B in limited amount does not suppress the MT and it improves the mechanical properties in compression, reducing the cracking behavior in comparison to the binary alloy.