Design of CrxFe1−xMnCoNiGeSi high-entropy alloy with large barocaloric effect

Abstract

Being a crucial research frontier, high-entropy alloys advance traditional materials in mechanical properties under various conditions. Nonetheless, other functions, like magnetic, electrical, and optical properties, of high-entropy alloys are still deficient. This paper presents a high-entropy system exhibiting a large barocaloric effect. Experimental results confirm that equiatomic FeMnCoNiGeSi and CrMnCoNiGeSi are high-entropy solid-solutions with hexagonal and orthorhombic structures at room temperature, respectively. Further tuning Fe/Cr ratio in a CrxFe1−xMnCoNiGeSi high-entropy system establishes a thermal-induced hexagonal–orthorhombic structural transformation. For the alloy with x = 0.44–0.50, the structural transformation occurs at room temperature and can be induced by applying or withdrawing hydrostatic pressure. The barocaloric effect reaches −30.6 J kg−1·K−1 when withdrawing hydrostatic pressure from 5 to 0 kbar, and the entropy change per 1 kbar is comparable to widely studied intermetallic compounds.