Effect of Dry Friction on the Subsurface Structure of a Sintered Al–7Fe–38Sn Composite Material

Abstract—The subsurface macrostructure of a sintered Al–7Fe–38Sn composite material, which forms during the rotation of a flat steel bar pressed against it, is investigated. A zone of intense plastic flow is found to form under the friction surface of the composite material due to thermal softening. The zone size and the degree of refinement of structural elements in it increase as the applied pressure and the sliding velocity increase. The plastic flow zone thickness is ≈200 μm at a pressure of 15 MPa and increases with the pressure. A thin layer with a homogeneous ultrafine-grained structure forms between the friction surface and the plastic flow zone.