MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Cu-CuO COMPOSITES PRODUCED BY HOT PRESSING OF COPPER POWDER

The article presents results of studying microstructure and mechanical properties of a composite material (Cu-CuO). The samples were taken from copper electrical contacts for electric welding machines manufactured by hot pressing PMS-1 powder under of «Uralelectromed». The microstructure was studied using scanning electron microscopy and scanning probe microscopy. The mechanical properties were determined by nanoindentation using the authors’ technique, which involves converting the indentation diagram F(h) into the tensile diagram σ(ε). Metallographic studies have shown a small grain size (~10 μm), the content of cuprite CuO inclusions of ~1 μm in size with faceted morphology was close to 20%. The results of measuring the mechanical properties: Young’s modulus E = 119.89±5.75 GPa, hardness H = 2.28±0.15 GPa; elastic recovery of the material R = 5.54±2.33%; plasticity characteristic δА = 94.46±2.33%; yield strength σт ≈ 600 MPa. Evaluation of mechanical stresses due to the two-phase nature of the composite material Cu-CuO showed that the additional pressure, related to the length of the rupture line, is approximately 50 times greater than the external force, and this can be the main reason for the failure of the products.