Molecular dynamics study on the effect of interstitial hydrogen clusters on the slip of edge dislocation in tungsten

Interstitial hydrogen (H) clusters with rock salt structure exhibit energy stability in tungsten (W) and play a crucial role in enhancing its hardness. However, the underlying physical mechanisms and the specific hardening behavior remain unclear. To this end, we systematically investigate the effect of the H cluster on the slip behavior of an 1/2 [111] (11¯0) edge dislocation in W by using the molecular dynamics method. We first study the slip of the edge dislocation in the absence of the H cluster, which reveals typical phonon drag control characteristics. Based on this, a slip drag coefficient B (T) is obtained, enabling accurate prediction of the dislocation mobility under various temperatures and stresses. In the presence of H clusters, the hardening effect in W is significantly enhanced. Notably, the geometric parameters of the H cluster, i.e., height and diameter, exert significant regulatory influence on the slip behavior of the edge dislocation through a quantitative correlation. Furthermore, the critical resolved shear stress (CRSS) displays a slight dependence on temperature within the range of 100 K-800 K, indicating that the dislocation motion is primarily governed by the geometry of the H cluster. These results provide new insights into the mechanisms of H-induced irradiation hardening in W, offering valuable data to support the development of high-performance W-based materials with enhanced irradiation resistance and long-term service stability.