Molecular Dynamics Simulation of Crack Propagation in α-Iron at Cryogenic Temperatures

Abstract

Crack propagation in α -iron has been studied by means of molecular dynamics at cryogenic temperatures to study the atomic scale phenomenon at the crack tip during the crack propagation. The calculations were made on the (110) or (100) plane having a crack in the [110] and [010] direction, respectively. Changing the stress intensity factor with time the deformation was taken place. The fracture toughness was defined as the stress intensity factor where the crack propagated spontaneously. In (110) plane the dislocations were produced from the crack tip and the crack tip comes to be dull at 300 and 80K whereas at 10K the dislocation was not produced and the crack propagates spontaneously. Consequently the fracture toughness decreased with decreasing temperature. In (100) plane even at 300K the crack propagated spontaneously. In this plane decreasing temperature brought the increase of fracture toughness.