Structural-phase transformations and short-range order evolution in the Fe–Cr system during mechanical alloying

Using Mössbauer spectroscopy on $^{57}$Fe nuclei and X-ray diffraction, the mechanism of mechanical alloying in a planetary ball mill of the Fe–Cr nanocrystalline system in a concentration range from 20 to 48 at.% Cr has been studied in detail. It has been established that mechanical alloying occurs in one stage at a concentration of up to 30 at.% Cr and in three stages at higher concentrations. The change in the mechanism of mechanical alloying occurs as iron is saturated with chromium and is caused by the inversion of the sign of the mixing energy from negative to positive.