PHASE TRANSITION RESEARCH ON Fe-2Mn ALLOY POWDERS PREPARED BY GAS ATOMIZATION

摘要

Fe-Mn based alloy has the potential as "third generation" advanced high strength steels (AHSS) for automotive due to its excellent comprehensive properties. The present paper considered the structure and phase transition of Fe-2Mn alloy gas-atomized powders. It was found that only bcc structure ferrite obtained when the temperature was at room temperature, then the ferrite → hcp-ε phase → γ-austenite and ferrite → γ-austenite phase transition was triggered with the temperature increasing. Results of Differential Scanning Calorimeter (DSC) measurement showed that the ferrite → ε and ferrite → austenite phase transition occurred at 858°Cand 910°C, respectively, transition from ε phase to γ-austenite occurred at 1158°C. Dynamics analysis was conducted on solid phase transformation, nucleation and the free energy of solid phase transition were calculated, aimed to clarify the solidification process.