Effect of Cr and N on the Martensitic Transformation in Fe‐8%Mn Alloys

The influence of Cr and N on the transformation temperatures of a Fe‐8%Mn alloy has been investigated by means of equilibrium thermodynamics and dilatometry. The addition of Cr and N resulted in the presence of ferrite or α'‐martensite at room temperature, with the microstructure transforming to a single phase austenitic microstructure with increasing temperature. Only high amounts of Cr or N in excess of 0.2% prevented the transformation to a single phase austenitic microstructure. The addition of alloying elements resulted in a decrease of the martensite start temperature M_s. The effect on the austenite start temperature A_s was smaller. The effect of thermal cycling resulted in a stabilization of the transformation temperatures. More cycles were required to reach stable phase transformation temperatures when N was added to Fe‐Mn‐Cr alloys.