Phase transitions in an Fe–9Al–30Mn–2.0C alloy

The as-quenched microstructure of Fe–9Al–30Mn–2.0C alloy is austenite phase containing fine (Fe,Mn)3AlC carbides. When the alloy was aged at 900–1100 °C and then quenched, both large and extremely fine (Fe,Mn)3AlC carbides could be observed simultaneously within the austenite matrix. This feature has never before been observed in FeAlMnC alloy systems. In addition, the Al and Mn concentrations in the coarse (Fe,Mn)3AlC carbides formed on the grain boundaries were found to vary drastically with the aging temperature.