Metastable mkscibility gap island in Fe- Ni- Mn ternary martensitic alloys

Abstract

The nose temperature of the hardening rate on the reciprocal temperature- time diagram (C- curve), was raised as the Ni and Mn contents were increased. This result showed the existence of a solubility limit surface in the bcc phase of the ternary Fe- Ni- Mn system. Possible combinations of the energy parameters of Fe- Ni, Fe- Mn and Ni- Mn binary systems were de%duced from the extent of the miscibility gap island by application of J. L. Meijering's treatment. Because the energy parameter of Ni- Mn system had a large negative value, the zonerich in Ni and Mn should be ordered. The intense hardening response observed in the 10 to 12% Ni, 5 to 6% Mn alloy is interpreted in terms of the relation between the solubility line and the martensitic region.