Elastocaloric effect with plateau-shape adiabatic temperature change in Ni-Co-Fe-Ga strain glass alloy

Elastocaloric effect (eCE) is a very promising candidate for using in non-vapor compression refrigeration, which is highly efficient and eco-friendly. However, designing elastocaloric alloys with a wide reversible working temperature window at low stress is still challenging. In this work, the transition behaviors, microstructural evolutions and the eCE of a series of Ni55-x Co x Fe19Ga27 alloys were systematically studied. The Ni44Co11Fe19Ga27 strain glass (STG) alloy exhibits a plateau-shape eCE, which show an average temperature change (Delta T Adia) of similar to 2.3 K covering a wide reversible working temperature range (Delta T rev) from 135 K to 200 K. The unique eCE behavior of STG stems from that the random distribution of local free energy of the martensite coupled with the small transition energy barriers, which leads to a wide transition-temperature range and decreased hysteresis. The Ni44Co11Fe19Ga27 STG alloy achieves a balance between the considerable Delta T Adia and wide Delta T rev, resulting in an optimal comprehensive elastocaloric performance and contributing to improving the efficiency of elastocaloric refrigeration.