Cementite formation in copper matrix under mechanical activation using carbon media

Abstract

We studied the structure and phase transformations of nanocrystalline alloys prepared with mechanical alloying (MA) and annealing by milling copper and iron powders with graphite and xylene. At an early stage of MA, a supersaturated solid solution of iron is formed in copper, regardless of the carbon-precursor type used. In the case of graphite, the formation of iron carbides occurs at a later stage of milling. MA in xylene results in an insignificant amount of carbon phases. Heat treatment leads to the formation of nanocrystalline copper composites with 30 vol.% Fe3C in the two cases of using graphite and xylene. The grain size (30 nm) of the annealed (800 °C) Cu + Fe3C composite produced by MA with xylene is five times less than that of the annealed sample produced with graphite.