Phase Composition of Light-Weight Steels and Alloys Based on the Fe–Mn–Al–C System

A Thermo-Calc program is used to calculate isothermal and polythermal sections of diagrams and phase composition for a series of alloys of the Fe–Mn–Al–Si–Mo–C–N system. Microstructure of these alloys is studied after quenching, hot and warm deformation, and ageing at 550°C. It is established that the phase equilibrium diagram of the Fe–Mn–Al–C system may be used for predicting alloy structure for this system after different forms of treatment. Alloys with a single-phase γ-region in the range 1000–1200°C and containing 20% or more Mn should contain more than 1.5% C with an Al content of 7.5% and more than 2% C with a 9% aluminum content.