Modeling and simulation of microcrack propagation behavior under shear stress using phase-field-crystal

Abstract

Phase-field-crystal (PFC) method is applied to simulate the propagation behavior of microcrack under shear stress in single crystal, which is seldom touched before. The microscopic mechanism is explored through the center precast microcrack on the (111) crystal plane in face-centered cubic (FCC) crystal. The influence of different factors on the crack propagation behavior is analyzed. Results show that the crack shape has influence on the occurrence of propagation. Propagation occurs earlier if the crack contains sharper inner angles, otherwise occurs later. Moreover, crack shape also affects the direction of propagation. The rate of applied shear stress can produce effect on the propagation speed, without altering the specific process of crack propagation. Improving shear rate can accelerate propagation. The initial orientation angle of solid phase has a great influence on the propagation mode and morphology of crack. Curves of change in free energy obtained in this work all monotonically ascend. We can divide the curves into five stages, corresponding to different shear strain stages. When simulation area is slightly small or shear rate is relatively large, the curve contains only three stages. Through this research, the PFC simulation is proved to be an effective means to study microcrack propagation behavior under applied shear stress.