Thermal conditioned decomposition of metastable structures in Fe-4%C-12%Cr-13%V rapidly solidified powder

Rapidly solidified powder with Fe-4%C-12%Cr-13%V chemical composition was a nnealed at various temperatures between 150 and 700 degreesC. Powder specim ens prepared by such a way were subjected to the microstructural evaluation , analysis of phase constitution and microhardness measurements. Mentioned characteristics were assessed as a function of both the annealing temperatu re and the powder particle size. It has been determined that below the temp erature of 500 degreesC, no significant changes had commenced. Annealing at 500 degreesC and higher temperatures led to the metastable austenite-b.c.c . transformation and intensive fine carbides precipitation. The temperature at which the mentioned transformations start and finish and the kinetics o f transformations, are closely related to the powder-particle size. Microst ructural changes and phase transformations result in microhardness peak tha t was determined for specimens processed at 550 degreesC. Higher annealing temperature induces both the complete gamma -b.c.c. transformation and the growth of precipitates that decreases the powder microhardness considerably .