Cracking in a Fe–25Mn–3Si–3Al Steel

Fe-25Mn-3Si-3Al steels obtained much attention because of their excellent mechanical properties. However, the fracture behavior of the steels remains unclear. In this study, Fe-25Mn-3Si-3Al steels were ex situ tensile strained and tested by a transmission electron microscope to investigate the relationship between crack and twins. The propagation of crack was examined and related to the dislocation slip and twinning. Cracks initiate related to the moving of dislocations and propagate along the slip bands. Twins parallel and inclined to the crack are produced during crack propagating. The inclined twins notably block and blunt the crack, whereas the parallel twins exhibit an insignificant effect.