Studies on the Equilibrium State of Fe-C-Zr Alloy.

Many investigators such as Allibone-Sykes^<(1)>, Vogel-Tonn^<(2)>, Wallbaum^<(3)> and Vogel-Lohberg^<(4)> have already studied about the alloys of the system Fe-Zr-C. But the equilibrium diagram of the system is yet far from complete. We have also studied about this alloy and by the application of dilatometric and magnetic analysis as well as microscopic and X-ray examination, a portion of the diagram, iron rich part, was made clear. Namely, in the range of low carbon, the following peritecto-eutectoid reaction was found to occur at about 810℃ and the alloys of this range have a fine grained eutectoid structure of α iron+ZrC+η ( a binary solid solution composed of Fe and Zr) without Fe_3C, γ iron+η ^^←__→ α iron+ZrC. While in the high carbon range, another peritecto-eutectoid reaction γ iron + ZrC ^^←__→ α iron+Fe_3C takes place at about 750℃ and the alloys of this range have a fine grained eutectoid structure of α iron+ZrC+Fe_3C phases without ηphase. This structure is the so-called fin