The mechanism and kinetics of initial stage of mechanical alloying in Si(Al, Mg, Cr)9957Fe1 binary systems

X-ray diffraction and Mössbauer probe spectroscopy data on mechanically alloyed binary systems of the Si(Al, Mg, Cr)9957Fe1 composition have been analyzed within the framework of the energetic approach. It has been established that the initial stage of mechanical alloying is preceded by a “preparatory” period, during which grains of a main component (element) reach critical size Lcr, followed by the alloying process per se. It has been shown that, the maximum of derivative dN/d(logD) (N is the yield of reaction products, and D is the mechanical energy dose), with the maximum corresponding to grain size Lmax = 17 nm irrespective of the type of the main component, is a universal characteristic when considering the kinetics of the initial stage of alloying. The chemical interaction of a main component with Fe has been found to play the decisive role in the kinetics of mechanical alloying, with the significance of this role increasing in a series Mg, Al, Si, and Cr. A phenomenological explanation has been given to the linear N(D) dependence at the linear dependence of the specific surface area of grain boundaries on the mechanical energy dose.