Thermal Conductivity Properties of Ti-V-Cr-Fe-M (M =Mn, Co, Sc and Ni) High Entropy Alloys

Metal-hydride solid state hydrogen storage (H-storage) has the advantages of high bulk density, good safety, easy operation and low operating cost, and is considered to be the most ideal H-storage method. High entropy alloys (HEAs), which contain at least five principal elements and each with an atomic percentage in the range of 5-35%, have gained continuous increasing attention in the material science community. Since large entropy encourages the generation of single-phase solid solutions with severe lattice distortions and more suitable reaction sites, HEAs have become a research hotspot for better performance in hydrogen storage. Body-centered cubic (BCC) alloy systems can theoretically store double amounts of hydrogen compared with commercial metal hydrides at room temperature, and BCC structural HEAs have shown the potential to reach this theoretic limit. The thermal conductivity of HEAs seriously affects its hydrogen storage performance, but little research has been conducted on the thermal conductivity of HEAs. In this study, as-cast V35Ti35Cr10Fe10M10 (M = Mn, Co, Sc and Ni) HEAs were fabricated by arc-melting. The microstructure and thermal conductivity behavior of the HEAs were systematically investigated. It is found that the main phase of the HEAs is a BCC-structured solid solution. The alloys also have high thermal diffusivity, specific heat capacity and thermal conductivity. The V35Ti35Cr10Fe10Sc10 sample exhibit the highest thermal conductivity of 2.865W/(m & sdot;K) at 100 degrees C. The factors affecting the thermal conductivity of HEAs were systematically analyzed. This study provides a new perspective on alloys applied to solid-state hydrogen storage.