Dislocations emission and crack extension at the atomistic crack tip in body-centered-cubic metal Mo

The behaviors of a crack in body-centered-cubic metal Mo under different loading modes were studied using the molecular dynamics method. Dislocation emission was observed near the crack tip in response to mode II loading with θ = 0° in which θ is the inclination angle of the slip plane with respect to the crack plane, and two full dislocations were observed at the stress level of KII = 1.17 MPa m1/2 without any evidence of crack extension. Within the range of 0° ≤ θ ≤ 45°, crack extension was observed in response to mode I loading, and the effect of crystal orientation on the crack propagation was studied. The crack propagated along the [111] slip direction without any evidence of dislocations emission.