3570.     VOGEL, R., AND DÖRING, W.  [Iron-Cementite-Manganese Carbide-Manganese.]  Arch. Eisenhüttenw., vol. 9, 1935, pp. 247-252; Chem. Abs., vol. 30, 1936, p. 710.

        Former investigations of this system and parts of it were enlarged and completed by establishing the constitutional diagrams on the basis of heats of reaction and structure.  Mn and Mn₃C do not form, as indicated previously, an uninterrupted series of solid solutions with a maximum temperature, a transition equilibrium occurs at solidification between 1.5 and 2.9% C, which leads toward higher C contents, to a minimum temperature.  A new transformation of Mn carbide was observed at 1,050°.  Four kinds of crystals were found in the system Fe-Fe₃C-Mn₃C-Mn:  Ternary solid solutions of a(δ)-Fe with C and Mn, which are restricted to a small range in the Fe-corner; ternary solid solutions of γ-Fe with C and Mn with a very extended range; ternary solid solutions of γ-Fe with C and Mn with a very extended range; ternary solid solutions of γ-Mn with C and Fe (area +β₄v₃); and solutions Fe₃C and Mn₃C (area C β₄v₃v₁).  The cementite does not form solid solutions with the excess Fe but the Mn₃C does with excess Mn.  The conditions are explained in detail by the diagram.  A table shows the location of the characteristic points a, β, γ, δ, and ε for the equilibria of the Fe-Mn-C alloys in solid state.  Various structures illustrated in photomicrographs.