Application of a New Model to the Interphase Precipitation Reaction in Vanadium Steels


Abstract:

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 vanadium diffusivity in ferrite have been identified. The model establishes predictive correlations between 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 interphase 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 spacing is known, it is possible to predict the intersheet spacing and width as a function of temperature.

Keywords:

vanadium microalloyed steels, vanadium carbide (VC), Interphase precipitation, vanadium diffusivity in ferrite, isothermal transformation.


Author:

P. Li and J. A. Todd

Affiiation

Departments of Materials Science and Mechanical Engineering,University of Southern California, Los Angeles, CA 90089-0241


Source:

Metallurgical Transactions A, vol. 19A, No. 9, 1988, pp. 2139-2151