Impact of Reversed Austenite on the Impact Toughness of the High-Strength Steel of Low Carbon Medium Manganese
We elucidate the relationship between the volume fraction of austenite and the Charpy impact toughness in a medium-Mn steel in terms of microstructural evolution with impact temperature. Different from retained austenite in the matrix after direct quenching, sub-micron lath-shaped morphology-reversed austenite in medium-Mn steel was produced by intercritical annealing. We found that reversed austenite steadily affected the fracture mode; only ductile fractures and dimples decreased with decreasing impact temperature. After the impact fracture test, the content of reversed austenite in the matrix increased slightly with a decreasing impact temperature due to the stability of the austenite grains caused by recrystallization of α′ martensite. Reversed austenite slightly decreased during the impact process with a decreasing impact temperature.
The authors gratefully appreciate the financial support by the National High-tech R&D Program (863 Program) No. 2015AA03A501.
Conflict of interest
The authors declare that they have no conflict of interest.
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