[SY-E6] Phase Field Crystal Simulation of Crack Extension and Brittle-Ductile Transition Behavior on Nano-Scale
Phase field crystal (PFC) method is used to simulate cracks propagation as a function of grain orientation. The results show that when the direction of tensile stress is perpendicular to the grain orientation, the crack exhibits cleaving extension characteristics with straight and smooth edges. As the angle between the grain orientation and the direction of the applied stress changes, the extension of the cracks begins to present a structure with saw teeth on the edge. Then, with the change of the angle increasing, a dislocation is emitted in front of the crack tip. Along with the dislocation slipping, it generates a series of micro holes. These holes further develop and grow to connect each other, and form a crack, which presents a ductile crack growth process. It can be seen that the change of the angle between the direction of the applied stress and the orientation of the grains can lead to a transformation of the ductile-brittle behavior of the fracture.