The influences of crystal orientation and crack interaction on the initiation of growth and propagation mode of microcrack: A phase-field-crystal study

Phase-field-crystal (PFC) method is applied to study the influences of crystal orientation and crack interaction on the initiation of growth and propagation mode of microcrack under uniaxial strain in nanocrystal system. The microscopic mechanism is explored through mono- and dual-crack systems. Results show that the crystal orientation and crack interaction have no influences on the initiation of growth of microcrack, all simulation systems have an identical critical strain of crack growth. On the other hand, the two influential factors can observably alter the propagation mode of microcrack. With the increase of crystal orientation, crack propagation mode changes from cleavage mode to a mixed-mode of ductile fracture and cleavage. The influences of crack interaction on the propagation mode of microcrack are various. If crack tips move in the same direction, crack propagation mode can be changed. On the other hand, if crack tips move toward each other, crack propagation mode will not be varied, but the specific interaction results are different depending on the value of crystal orientation. Through this research, the PFC simulation is demonstrated to be an effective means to study multiple microcrack propagation behavior.