Over 10 K elastocaloric effect in ω-phase-free TiZrNbSn alloy

Ti-based shape memory alloys are promising for elastocaloric cooling but typically fail to meet the practical 10 K adiabatic temperature change (ΔTad) threshold. Here, we propose a microstructural design to eliminate the ω phase that suppresses martensitic transformation, thereby enhancing ΔTad. The designed ω-phase-free Ti69Zr17Nb11Sn3 alloy exhibits remarkable ΔTad of 11.6 K (Pt sensor) and 18.52 K (IR camera), and is the first Ti-based alloy to exceed 10 K. Combined with low critical stress (σcr), an ultrahigh specific adiabatic temperature change (ΔTad/σcr) is achieved. This work presents a novel and effective approach for improving the elastocaloric performance of Ti-based alloys.