Structural Diagrams of the Ternary Fe-Cr-N System

Abstract

In the present work, the isothermal structural diagrams of the Fe-Cr-N system in the range of compositions between 0 to 40% chromium and up to 1% nitrogen were constructed at various temperatures below 1300°C in accordance with the results of a previous work. From the considerations on the transition of phases and the tranformation planes, the structural diagrams were also obtained with various cross-sections of 0.1% nitrogen, and 13, 18% and 26% chromium. In the ternary Fe-Cr-N system, the existence of the following three invariant reactions was pressumed: (1) L+α\ ightleftarrowsγ+Cr₂N above 1300°C, (2) γ+Cr₂N\ ightleftarrowsα+CrN about at 790°C and (3) γ+CrN\ ightleftarrowsα+Fe₄N about at 760°C.