Phase transformations in an Fe–8Al–30Mn–1.5Si–1.5C alloy

The phase transformations in an Fe–8Al–30Mn–1.5Si–1.5C alloy has been investigated by means of transmission electron microscopy. In the as-quenched condition, the microstructure of the alloy was austenite phase containing fine (Fe,Mn)3AlC carbides. The fine (Fe,Mn)3AlC carbides were formed during quenching by a spinodal decomposition. When the as-quenched alloy was aged at temperatures ranging from 550 to 1000°C, the phase transformation sequence as the aging temperature increased was found to be (Fe,Mn)3AlC carbide+D03→(Fe,Mn)3AlC carbide+B2→(Fe,Mn)3AlC carbide+α→γ. This transformation has never before been observed in the Fe–Al–Mn–C and Fe–Al–Mn–Si–C alloys.