The effect of Mn and Al contents on the solvus of κ phase in austenitic Fe-Mn-Al-C alloys

It is known that the precipitation of the κ phase has significant effect on the mechanical properties of Fe-Mn-Al-C alloys. The κ phase may be present along the grain boundaries (inter-granular) or within the grains (intra-granular). The effect of Al and Mn contents on the solvus of both inter- and intra-granular κ phase was investigated for a composition range of Fe-(21-32 wt.%)Mn-(2-10 wt.%)Al-1C. The results clearly indicate that the addition of Al raises the solvus of both inter- and intra-granular κ phases significantly, while the addition of Mn only causes slight reduction of the solvus. The implication of this result on the development of this alloy is also discussed. (orig.)