Premature Fracture Mechanism in an Fe-Mn-C Austenitic Steel

摘要

We investigated the cause for poor ductility in austenitic Fe-Mn-C steels under a specific condition. Tensile tests were performed on an Fe-17Mn-0.3C steel at 273 K, 294 K, 323 K, 373 K, 423 K, 473 K, and 523 K (0 °C, 21 °C, 50 °C, 100 °C, 150 °C, 200 °C, and 250 °C). Microstructural observations were conducted by optical microscopy, atomic force microscopy, scanning electron microscopy and the X-ray diffraction method. ε-martensitic transformation was concluded to be the major cause for the poor ductility. The cracks were initiated from the annealing twin boundaries that interacted with the ε-martensite.