Dislocation Source and Pile-up in a Twinning-induced Plasticity Steel at High-Cycle Fatigue

Dislocation behaviour of a twinning-induced plasticity (TWIP) steel subjected to high-cycle fatigue tests is investigated in the present study. Grain boundaries are important sources dislocation generation during tests, contributing increase density. Continuous emission dislocations from grain observed many grains. Inclusions can sustain large pile-ups at inclusion interfaces, leading high stress concentration and therefore acting as potential sites microcrack nucleation. In contrast, annealing twin relatively weak for pile-ups. When number pile-up large, crossover glide inside twins. The boundary low so that could not act initiation.