EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

A particular need to increase the efficiency of gas turbine engines induces the searching for new materials with higher performance than currently used commercial alloys. One of the prospective candidates for high-temperature applications is the so-called refractory high entropy alloys (RHEAs). RHEAs are often based on body-centered cubic (bcc) or ordered B2 solid solution and can contain Laves, ZrxAly, M5Si3, or MC phases. However, the enormous amount of possible compositions perplexes a choice of the microstructure type and constitutive phases for a better properties combination obtaining. Recently, a promising approach to get coherent B2 precipitates in the bcc matrix was reported. Nevertheless, alternative methods must also be considered. This study introduces a CALPHAD-aided strategy to design eutectic RHEAs (ERHEAs) based on the light-weight Al-Cr-Nb-Ti-Zr alloys system. The multielement origin of program ERHEAs was shown to be a reason for appearing a unique eutectic B2/C14 Laves phase microstructure. Mechanical properties evaluation exhibited an exponent-like strength enhancement and ductility drop when a transfer from a single-phase to eutectic microstructure occurs.

The study was supported by the Russian Science Foundation grant № 19-79-30066.