1. Large reversible multicaloric effects over a broad refrigeration temperature range in Co and B co-doped Ni–Mn–Ti alloys.
- Author
-
Li, Bo, Liu, Zhenpeng, Li, Dou, Feng, Zhenyu, Zhu, Jiaxi, Zhong, Hong, and Li, Shuangming
- Subjects
- *
MAGNETIC entropy , *VAPOR compression cycle , *DOPING agents (Chemistry) , *MAGNETOELASTIC effects , *ADIABATIC temperature , *MAGNETIC structure - Abstract
Solid-state refrigeration is considered a promising alternative to traditional vapor compression refrigeration technology. Researchers demonstrated that Ni–Mn–Ti alloys have a remarkable elastocaloric effect. However, the Ni–Mn–Ti alloy can only operate under a uniaxial stress field due to its antiferromagnetic austenite, which narrows its range of refrigeration temperatures. Here, we activated the magnetism of the alloy by replacing some Ni atoms with Co atoms. The Ni–Co–Mn–Ti–B alloy demonstrates a reversible maximum magnetic entropy change(Δ S m) of 24.9 J kg−1 K−1 and achieves an adiabatic temperature change of 7.8 K under a 7 T magnetic field. Additionally, we demonstrate that adding boron (0.2%) can improve the mechanical properties and cyclic stability in Ni–Mn–Ti alloys. The elastocaloric effect of 21.3 K with high cycle stability (1013 cycles) were successfully achieved in the directionally solidified (Ni 35 Co 15 Mn 35 Ti 15) 99.8 B 0.2 alloy. Furthermore, we have demonstrated that the magnetoelastic coupling effect can effectively extend the refrigeration temperature range. The alloys achieved large caloric effects in the temperature range of 240 K–340 K. This provides a new strategy for designing high-performance materials for wide-temperature-domain refrigeration. • The addition of Co activates the magnetic structure coupling of Ni–Mn–Ti alloy. The alloy exhibits a reversible maximum magnetic entropy change Δ S m of 24.9 Jkg −1 K −1 and achieves an adiabatic temperature change of 7.8 K under a 7 T magnetic field. • The addition of B can effectively improve the strength and ductility of the alloy. The material shows a highly stable (1013 cycles) elastocaloric effect of 21.3K. • The material can achieve a continuous refrigerable operating temperature range from 240 K to 340 K by combining elastocaloric, magnetocaloric and magnetoelastic coupling effects. • The stress-assisted method can not only improve the reversibility of caloric effect , but also broaden the temperature range of reversible caloric effect and improve the refrigeration performance of the active refrigerator. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF