Structural features and properties of the alloy 84% wc-16% Co obtained by solid-phase and liquid-phase hot pressing. II. Influence of the temperatureat which the specimens are made on their physicomechanical properties

We have studied the changes that occur in the resistivity, the transverse b ending strength, and the fracture toughness (cracking resistance) of a hard alloy obtained by hot pressing at about 500 MPa and sintering over a wide range of temperatures (950-1450 degreesC) as well as the how those paramete rs are affected by solid-phase and liquid-phase annealing. The porosity dep endence of the resistivity is shown not to be single-valued. Other factors affect the resistivity, e.g., the degree of particle interaction and the st ate of the structural components, which vary with the porosity. The resisti vity curve for hot-pressed specimens has an inflection in the region of 120 0 degreesC. The resistivity increases at a faster rate at lower temperature s. In the temperature range studied the porosity dependence of the transver se bending strength and the fracture toughness is linear: sigma (b) = sigma (0)(b)(1 - 3.53 Theta) and K-1c = K-1c(0)(1 - 3.44 Theta). Prolonged solid -phase annealing of hot-pressed specimens improves their mechanical propert ies owing to a decrease in porosity.