Abstract
Iron–manganese alloys containing 0–4 %Mn have been nitrided in the range 450–550°C. The effect of manganese on the activity of nitrogen was found to be given by
The precipitates in equilibrium with the various alloys at 550°C were: 0·53%Mn, Fe4N; 0·785–1·18%Mn, η-Mn3N2; 2·15 %Mn, ζ-Mn5N2. The solubility of η-Mn3N2 was determined approximately.