Strengthening mechanisms in CrMoNbTiW refractory high entropy alloy

We have investigated the strengthening mechanisms of as-cast CrMoNbTiW BCC refractory high entropy alloy (RHEA). The cast RHEA was deformed at a constant strain rate of 10(-3) s(-1) and a temperature range of 1100-1300 degrees C. The various factors contributing to the overall strength of the cast alloy are explored with comprehensive experimental evidence. In as-cast RHEA, solid solution strengthening is the dominant mechanism among other factors. A modified Varvenne's solid solution strengthening model is used to predict the yield strength (YS) of the RHEA at high temperatures. The experimentally determined YS exhibits a strong temperature dependence, and the predicted YS values are significantly affected by the temperature-dependent material constants. The absolute value of the predicted YS depends on the shear modulus, whereas the variation of YS with temperature is affected by the Poisson's ratio. Moreover, our study demonstrates that it is feasible to predict the high temperature YS using material constants from literature besides DFT studies.