Influence of titanium addition on the microstructure of the novel ferrous-based stainless steel

The microstructural characteristics of the Fe-9Al-30Mn-1C-5Ti (wt.%) alloy were determined by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectrometry. The microstructure of the alloy was essentially a mixture of ( gamma + TiC sub(x) + ( alpha + B2 + DO sub(3))) phases during solution treatment between 950 degree C and 1150 degree C. The TiC sub(x) carbide had a face-center-cubic structure with a lattice parameter a of 0.432 nm. When the as-quenched alloy was subjected to aging treatment at temperatures of 450-850 degree C, the following microstructural transformation occurred: ( gamma + TiC sub(x) + Kappa + ( alpha + DO sub(3))) -- ( gamma + TiC sub(x) + Kappa + ( alpha + B2 + DO sub(3) + TiC sub(x))) -- ( gamma + TiC sub(x) + Kappa + Kappa ' + ( alpha + B2 + DO sub(3))) -- ( gamma + TiC sub(x) + ( alpha + B2 + DO sub(3))). Addition of Ti promotes the formation of the alpha phase at high temperatures.