Influence of alloying on ductility and mechanical properties of W–Ta–Cr–V high-entropy alloys

Abstract

The challenge of poor ductility poses formidable obstacles for tungsten (W) in its role as a first-wall material. However, the promising prospect of W-based high-entropy alloys (HEAs) holds the potential to address and ameliorate the issue. Through ab initio calculations, the elastic properties of the experimentally observed W20Ta20Cr8V6 and WxTayCryVy (0≤x ≤ 21) HEAs were studied. By evaluating parameters such as atomic radii differences and valence electron concentrations, our results affirm the potential of W–Ta–Cr–V to form a stable body-centered cubic (bcc) high-entropy solid solution, aligning well with experimental observations. The mechanical properties of W–Ta–Cr–V alloys, especially their ductility, need to be carefully evaluated in order to make them widely used. Compared to the excellent mechanical properties of W metal, the formation of a high-entropy solid solution with elements such as W, Ta, Cr and V leads to a reduction in its mechanical properties. Nevertheless, the Cauchy pressure, Poisson's ratio, and B/G ratio of HEAs collectively suggest that the addition of ductile metals such as Vanadium (V) and Tantalum (Ta) can significantly enhance the ductility of W metal, offering a promising solution to the longstanding issue of brittleness associated with W metal.