Characteristics of the γ→α transformation in Fe-Mn alloys

The relationships between the lattice parameters of austenite and ferrite in Fe-Mn alloys and Mn content were established by means of X-ray diffraction and revised literature data. These results were used to calculate the dilatation due to the isothermal gamma-->alpha transformation. The dilatometric experimental results are in very good agreement with the calculations. It was found that the increase of hardness of the alpha phase is a linear function of Mn content and is mainly determined by the lattice strain of this phase. The Curie temperature of the alloy was established as a function of Mn composition. The austenite fraction and enthalpy difference between ferrite and austenite accompanying the gamma-->alpha transformation were also determined as a function of temperature and Mn content by means of isochronal DTA measurements. (C) 2002 Elsevier Science B.V. All rights reserved.