Formation of chromium carbides in copper matrix during mechanical alloying in carbon-containing media

Structural and phase transformations that occur during mechanical alloying (MA) and subsequent annealing of nanocrystalline Cu-Cr-C alloys obtained from copper and chromium powders and graphite or xylene as the source of carbon have been studied. It is shown that, when using graphite, a supersaturated Cu(Cr) solid solution and an X-ray amorphous Cr-C phase are formed during MA. Heat treatment leads to their decomposition and the appearance of Cr₃C₂ in the nanocrystalline copper matrix. When xylene is used as the source of carbon, no strongly supersaturated Cu(Cr) solid solution and no X-ray amorphous Cr-C phase are formed, but the same volume fraction of chromium carbide, i.e., 20–24 vol %, appears. When graphite is used, the carbide is formed after shorter times of MA.