Comparing the accuracy of melting temperature prediction methods for high entropy alloys

Refractory complex concentrated alloys (RCCAs) are a relatively new class of materials that can exhibit excellent mechanical properties at high temperatures, and determining their melting temperature (T-m) is critical to assess their range of operation. Unfortunately, the experimental determination of this property is challenging and computational tools to predict the T-m of RCCAs from first-principles calculations are highly desirable. We quantify the uncertainties associated with such predictions for two methods that can be used with density functional theory-based molecular dynamics and apply them to predict the melting temperature of equiatomic NbMoTaW. We find that a combination of free energy calculations of individual phases with a dynamical coexistence method can provide accurate results with the minimum possible computational cost. We predict the melting temperature for the RCCA NbMoTaW to be between 3000 and 3100 K. Published under an exclusive license by AIP Publishing.

Automated summary

Refractory complex concentrated alloys (RCCAs) are a new class of materials with excellent mechanical properties at high temperatures. Determining their melting temperature (T-m) is crucial for assessing their range of operation. However, experimental determination of this property is challenging, making computational tools highly desirable. In this study, we quantified the uncertainties associated with predicting T-m of RCCAs using density functional theory-based molecular dynamics. We employed two methods and found that a combination of free energy calculations and a dynamical coexistence method provided accurate results with minimal computational cost. We predicted the T-m of equiatomic NbMoTaW to be between 3000 and 3100 K.