Application of a new model to the interphase precipitation reaction in vanadium steels

A new model has been applied to the precipitation of vanadium carbide (VC) particles in sheets at austenite/ferrite interphase boundaries during the isothermal transformation of Fe-C-V steels. Linear relationships between the intersheet spacings, the VC particle sizes, and the square root of the vana-dium diffusivity in ferrite have been identified. The model establishes predictive correlations be-tween the interphase precipitate sheet widths, intersheet spacings, and boundary migration speeds as a function of isothermal transformation temperature, and shows that the time associated with the in-terphase precipitate repeat period is a constant for each alloy over the temperature ranges studied. From a single measurement of interphase boundary velocity in a volume where the intersheet spac-ing is known, it is possible to predict the intersheet spacing and width as a function of temperature.