Internal Oxidation during Intercritical Annealing of CMnSi TRIP Steel

The equilibrium internal oxidation of CMnSi TRIP steel at intercritical annealing temperatures in a +3 degrees C dew point N-2+10%H-2 atmosphere was investigated by means of high resolution transmission electron microscopy of cross-sectional samples. The experimental conditions are considered to lead to the selective internal oxidation of Mn and Si. The intercritical annealing however resulted in the formation of three types of isolated particles on the surface: 200-340nm size single crystal MnO oxide particles, crystalline 30-60nm size xMnO center dot SiO2 (1 <= x <= 4) and amorphous alpha-xMnO center dot SiO2 (0