Ideal strengths and thermodynamic properties of W and W-Re alloys from first-principles calculation

摘要

First-principles calculation, quasi-harmonic approximation and thermal electronic excitation have been combined to examine ideal strengths and thermodynamic properties of W and W-Re alloys. It is found that the ideal tensile and shear strengths of W are decreased due to Re alloying, with the easy cleavage plane of both W and W-Re alloys found in (100) plane. Moreover, the derived temperature-dependent elastic properties explain the "Re softening effect", and provide a deep understanding of the ductility of W-Re alloys as a function of the temperature. The results also reveal that Re alloying significantly increases the ductility of W, which is rare at low temperature in the temperature range 0-2000 K. The calculated results agree well with similar experimental observations in the literatures, and could explore their fundamental properties as well as various potential applications.