Molecular dynamics study of the effect of hydrogen on the mechanical properties of tungsten

The effect of hydrogen on the mechanical properties of single crystal BCC W as well as the intrinsic mechanism was investigated by using molecular dynamics method. The bond energy of tungsten atoms was computed and the results suggest that hydrogen atoms weaken the bonds. By simulating the response of tungsten under uniaxial tensile load, the stress-strain curves for different hydrogen concentration were obtained. It was found that hydrogen has great influence on the elastic modulus and plastic deformation mechanism. Moreover, the interaction between hydrogen atoms and dislocations was simulated. The qualitative relationship between yield stress and hydrogen concentration was obtained. All the numerical results suggest that the retention of hydrogen atoms causes significant degradation of the mechanical properties of tungsten.