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 firstprinciples 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 (delta chi), i.e., G x delta chi, accurately predicts yield strength (sigma y). This criterion outperforms other empirical parameters such as valence electron concentration (VEC), G, or delta chi alone. Specifically, higher G x delta chi correlates with higher sigma y. The sigma y of V25Nb25Mo25Cr25 exceeds that of other equiatomic alloys, agreeing with existing experiments, thereby validating the reliability of our approach. Following the G x delta chi criterion, we further design non-equiatomic V50xNb50-xMoxCrx bcc RMPEAs based on V25Nb25Mo25Cr25. We identify V15Nb15Mo35Cr35 as a target RMPEA, which exhibits the highest sigma y and good high-temperature softening resistance among all considered bcc RMPEAs. The universality of the G x delta chi criterion is confirmed not only by current calculations but also by available experiments, as evidenced by the maximum Pearson correlation coefficient between sigma y and G x delta chi. This work provides an effective paradigm for discovering high-strength bcc refractory alloys by strategically optimizing the G x delta chi metric.