Molecular dynamics simulation of intergranular fracture in austenitic steel containing precipitation

Molecular dynamics simulation is applied to study the crack propagation in austenitic steel containing precipitation. Based on the experimental results, models containing precipitation with two shapes and three volume fractions are constructed. The interactions of the crack with precipitation, dislocation, twin and stacking faults are investigated. It demonstrates that the crack propagation process is strongly related to the temperature and the characteristic parameter of the precipitation. However, the microstructure evolution and dislocation emission are more affected by the temperature. At the same temperature, the initial emission position of the dislocation is changed due to the variation of the precipitation shape. It also indicates that the peak dislocation density is weakly correlated with the single characteristic parameter of the precipitation. Combined with the variation of the crack propagation rate and the peak dislocation density with temperature, it illustrates a negative relationship between these two results.