As the environment continues to deteriorate, many researchers are exploring energy saving and environmentally friendly refrigeration technologies. Solid-state elastocaloric technology, which conserves energy and protects the environment, is recognized as a very competitive alternative to the conventional vapor-compression refrigeration.
Liu et al. demonstrate an intriguing class of elastocaloric materials called the Co-V-Ga Heusler-type shape memory alloys, which enable a large elastocaloric effect and ultra high cyclability.
“The combination of large elastocaloric effect and cyclability indicates the Co-V-Ga based alloys hold huge potential to be developed as high-performance elastocaloric matierals,” said author Zongbin Li.
Previously, Heusler-type shape memory alloys were known for their large refrigeration capacity and low criticial stress, but their intrinsic brittleness was a challenge.
The Co-V-Ga Heusler-type shape memory alloys, however, possessed excellent mechanical properties, making them better suited for refrigeration applications.
The researchers prepared the Co50V35Ga14Ni1 alloy using an arc-melting technology followed by annealing at 1373 degrees Kelvin for 48 hours. The adiabatic temperature changes on applying and removing the compressive stress were recorded by the K-type thermocouple at room temperature.
The researchers achieved large elastocaloric effect of up to minus 12.1 degrees Kelvin during the rapid unloading process and demonstrated excellent cyclability of more than 4,000 cycles for the Co50V35Ga14Ni1 alloy.
“The most surprising element was the excellent cyclic stability of the Co50V35Ga14Ni1 alloy,” said Li. “Cyclic satblity is a vital parameter of the practical refrigeration applications.”
The pronounced advantages in elastocaloric refrigeration may attract more research to Co-V-Ga-based alloys going forward and pave the way for further exploitation of high-performance fatigue-tolerant elastocaloric materials.
Source: “Large elastocaloric effect in a Heusler-type Co50V35Ga14Ni1 polycrystalline alloy,” by Cong Liu, Dong Li, Zonbin Li, Bo Yang, Haile Yan, Jianrong Li, Zhe Li, Xiang Zhao, and Liang Zuo, Applied Physics Letters (2021). The article can be accessed at https://doi.org/10.1063/5.0040768.
