Influence of regimes of mechanical activation on the structure and properties of the powder precursor of the copper-tin and alloys sintered on the their basis

The mechanism of formation of structural-phase state in the precursor powders of Cu + 20 % Sn during intensive mechanical activation in a planetary ball mill is shown. It is shown that the formation of precursor powders consists of a range of stages: the grinding of the powder particles, the passing of plastic deformation processes in them with the formation and decay of the new phase components, the formation of aggregates. It is found that the formation of the alloy is realized by the mechanism of liquid phase sintering with the advent of low-melting molten tin at electrocontact sintering of the precursor powders prepared by activation during up to 8 minutes. The electrocontact sintering of monophase powders with the structure consisting of a solid solution Cu (Sn) formed after mechanical activation during 20 min is realized by the mechanism of solid phase sintering and results to the formation of a homogeneous alloy based supersaturated solid solution Cu (Sn) with a macrogranular structure and many voids. The most rational duration of mechanical activation to produce a sintered copper-tin alloy tribotechnical purpose is 4-8 min.