Metallurgical structure and phase diagram of Fe–C–V system: comparison with other systems forming MC carbides

Abstract

AbstractLiquid–solid equilibria were studied in the Fe rich corner of the Fe–C–V system using differential thermal analysis (DTA), SEM, TEM, and electron probe microanalysis. A modified version of the DTA technique, quenched interrupted DTA, was employed to establish the solidification paths. Several transformations occurring just below the liquidus temperature are described and explained by reference to the peritectic reaction and a proposed metatectic transformation. The tie lines were determined at the liquidus temperature and an equation is proposed to predict the partitioning coefficient of V as a function of the composition of the alloy. The influence of other solute elements on the equilibria and on the microstructure was investigated. A comparison is drawn with some similar systems: Fe–Nb–C, Fe–Ta–C, and Fe–Ti–C. In particular, for all these systems, blocky, faceted carbides form in the melt even in hypoeutectic alloys.MST/622