Controlling microstructure and mechanical properties of Ti-V-Cr-Nb-Ta refractory high entropy alloys through heat treatments

In this study, we have investigated the microstructure and mechanical properties of two refractory high entropy alloys (RHEAs), Ti-V-Cr5-Nb-Ta Ti-V-Cr-Nb-Ta, in their as-cast heat-treated conditions. Both show almost single-phase BCC structure, while different size volume fraction secondary phases were formed after homogenisation heat treatment. The major phase was indexed as a complex C15 Laves structure with composition (Ti, Ta)(V, Cr, Nb) 2 . nanoindentation mapping indicates is very hard brittle, performing treatment leads to an improved hardness both alloys. correlations between changes microstructural evolutions are also discussed. • Microstructure RHEAs determined precipitates substitutional close ~2 times that matrix. A method proposed introduce fine dispersion RHEA.