The effect of titanium(Ti) doping on hydrogen incorporation in tungsten(W)：First-principles calculations

Using the first-principles methods, we investigated the structure, the mechanical properties, and solution and diffusion behavior of hydrogen impurity in the W-Ti lattice. The single H atom is energetically favorable sitting at the tetrahedral interstitial site nearest neighboring to the Ti atom in the W-Ti lattice. The minimum solution energy is about 0.498 eV. By analyzing the energy barrier curves, it is shown that the effect of titanium-doped tungsten on hydrogen migration behavior is small in the W-Ti lattice. Base on the elastic constants analysis, titanium-doped tungsten can withstand the degradation of mechanical strength induced by hydrogen effect. On the other hand, it is found that the ductility of pure W metal and W-Ti alloys can be improved substantially by hydrogen effect from the B/G ratio and the Poisson's ratio ν. However, the effect of the improved ductility is more obvious in the bcc pure W metal than that in the W-Ti alloys.