Tin Bronze Reinforced with Cu9Al4 Particles: Mechanochemical Synthesis and Consolidation by Sintering under Pressure

X-ray diffraction analysis and optical and electron microscopy have been used to study the effect of mechanical activation conditions of the Cu–12% Sn mixture with different Cu9Al4 modifier contents on the structure and phase composition and morphology of formed composites. The mechanochemical intro-duction of 10 wt % of the modifying additive into the matrix of mechanically synthesized tin bronze mainly results in the formation of a ternary Al0.05Cu0.9Sn0.05 solid solution of aluminum and tin in copper. In the case of the 20 wt % modifying additive, the final product contains a Cu0.9Sn0.1 tin solid solution in copper and Cu9Al4 intermetallics. Studies of the mechanical and tribological characteristics of the material prepared by sintering under a pressure showed that the intensity of wear of the material based on the Cu–12 wt % Sn mechanochemically synthesized bronze is insignificant lower than that of commercial bronze alloy CuSn10P; the coefficient of friction (f) decreases by ~1.3 times and the range of its values is sufficiently wide,
f = 0.7–0.9. The modification of the Cu–12 wt % Sn mechanically synthesized bronze with the Cu9Al4 inter-metallics allowed us to decrease the intensity of wear by 1.3 to 1.6 times and to substantially decrease the coef-ficient of friction (by 1.2 to 1.6 times). The stable value f = 0.5 is reached for the mechanically activated
Cu‒12 wt % Sn + 20 wt % Cu9Al4 composition. The introduction of the intermetallics results in the increase in the microhardness of the alloys by 1.6 to 2 times (to Hμ = 2730 MPa) compared to those of CuSn10P and mechanically synthesized bronzes.