Ultrahigh cyclic stability and giant elastocaloric effect in directionally solidified (Ni50Mn28Fe2.5Ti19.5)99.4B0.6 alloy
Ziqi Guan, Jing Bai, Yu Zhang, Jianglong Gu, Yudong Zhang, Claude Esling, Xiang Zhao, Liang Zuo
Abstract
ABSTRACT Cyclic stability of elastocaloric materials is critically important for practical applications in solid-state refrigeration. Ni-Mn-based Heusler-type alloys exhibit a large elastocaloric response to low driving stress. However, these alloys can only be worked for short-term cyclic operation due to their intrinsic brittleness . Here, we demonstrate the achievement of giant elastocaloric effect (eCE) and long-term fatigue performance in a directional solidification (Ni 50 Mn 28 Fe 2.5 Ti 19.5 ) 99.4 B 0.6 alloy. At 303 K, the maximum compressive strength and strain of the alloy can be as high as 2734 MPa and 20.5%, respectively. During fast loading and unloading with the stress of 435 MPa and the strain of 8%, giant adiabatic temperature change (ΔT ad ) of 25.1 K and -24.5 K can be obtained, respectively. In particular, a large ΔT ad of about 5.8 K is generated during cycling at 360 MPa stress and 3.5% strain, and can be maintained for more than 20,000 cycles.