An Investigation on the Titanium-Iron-Carbon System (2nd Report)

Abstract

The solid solubility ranges of the phases and their equilibrium relationships in the Ti-Fe-C system were studied by microscopic examinations and X-ray analysis. The results of investigation indicate that the following solid phases exist in this ternary system : titanium-rich solid solutions α or β, graphite, δ phase known as titanium carbide phase, TiFe phase, TiFe₂ phase and iron-rich solid solution α or γ, but no ternary compound is detected. The δ phase region is given as from 13 to 20 weight%C and the maximum solid solubility of Fe in this phase is about 15 weight%. A change of the C concentration in the δ solid solution has a greater effect upon the lattice parameter of the δ phase than that of Fe concentration. The solid solubility of ternary TiFe phase is given as from 52 to 54 weight% of Fe and the maximum solubility of C is considered to be less than 0.1 weight%Fe. The ternary TiFe₂ phase has a wide range of solubility of iron which extends from 69 weight pct to 77 weight pct of iron, and the maximum solid solubility of carbon in the TiFe₂ phase is considered to be less than 0.2 weight pct of carbon. The δ solid solution is in equilibrium with α or β titanium, TiFe phase, TiFe₂ phase, α or γ iron and graphite, and there exist two quasi-binary eutectic reactions of liquid\ ightleftarrowsδ+TiFe₂ and liquid\ ightleftarrowsδ+(Fe)_α.