First-principles investigation on mechanical behaviors of W–Cr/Ti binary alloys

Abstract

Using first-principles simulation, we have performed the study on the mechanical behaviors of body-centered-cubic W1-xCr(Ti)x binary alloys (0 < x < 0.1) as a function of Cr (Ti) composition. The lattice constants, elastic constants, Young's moduli, and shear moduli are investigated for single crystal W1-xCr(Ti)x binary alloys. Cr and Ti can, respectively, shrink and enlarge the lattice structure of W due to their different atomic radius. The influence of alloying on C11 is larger than that on C12 and C44 with the increase of Cr/Ti concentration. For polycrystalline W-based alloys, bulk modulus B, Young's modulus E, shear modulus G, Poisson's ratio v, Zener anisotropy factor A, Debye temperature ΘD, and B/G have been also calculated. All these quantities display regular change trend with increasing Cr/Ti concentration. Cr and Ti exhibit the opposite alloying effect on the thermodynamic stability of alloy. W1-xCr(Ti)x is energetically unstable (stable) with random Cr (Ti) concentration at any temperature considered in the current study. This result well approves the experiment on that the alloying element Ti can enhance the mechanical properties at ambient and intermediate temperatures.