Accelerated design of high-strength refractory multi-principal element alloys from first-principles calculations

To rapidly develop high-strength refractory multi-principal element alloys (RMPEAs), we systematically calculate elastic moduli and mechanical properties for a series of body-centered-cubic (bcc) RMPEAs using the first-principles method. By analyzing equiatomic V33Nb33Mo34 and V25Nb25Mo25X25 (X = Al, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W) bcc RMPEAs, we discover that the product of shear modulus (G) and electronegativity difference (δχ), i.e., G × δχ, accurately predicts yield strength (σy). This criterion outperforms other empirical parameters such as valence electron concentration (VEC), G, or δχ alone. Specifically, higher G × δχ correlates with higher σy. The σy of V25Nb25Mo25Cr25 exceeds that of other equiatomic alloys, agreeing with existing experiments, thereby validating the reliability of our approach. Following the G × δχ criterion, we further design non-equiatomic V50-xNb50-xMoxCrx bcc RMPEAs based on V25Nb25Mo25Cr25. We identify V15Nb15Mo35Cr35 as a target RMPEA, which exhibits the highest σy and good high-temperature softening resistance among all considered bcc RMPEAs. The universality of the G × δχ criterion is confirmed not only by current calculations but also by available experiments, as evidenced by the maximum Pearson correlation coefficient between σy and G × δχ. This work provides an effective paradigm for discovering high-strength bcc refractory alloys by strategically optimizing the G × δχ metric.