High-temperature strength and refractoriness of doped WC-Co-Ni-Re(Mn) hard alloys

Abstract

The regularities of oxidation of hard alloys (HA) in the “tungsten carbide-metal binder based on cobalt, nickel, rhenium, and manganese” system are established. It is revealed that the introduction of Ni-Re or Ni-Mn into the cobalt binder increases the temperature of the onset of active oxidation by 20–70°C and decreases its rate in the following order: Co-Ni, Co-Mn → (Co-Ni-Mn, Co-Re, Co-Ni) → Co-Ni-Re → Ni-Re. The character of the temperature dependence of the bending strength of the HA with Co-Ni and Ni-Mn binders is almost indistinguishable from that for the VK alloy, while the addition of Re into the binder abruptly changes this character. The HA strengthens somewhat (up to 20%) up to temperatures of 600°C for the Ni-Re binder and 800°C for the Co-Re binder; then its strength decreases but remains higher than for materials with cobalt and nickel binders. The maximal strength of the HA of the WC-Co-Ni-Re systems is attained in the range t = 600–800°C, which corresponds to the temperature of the working edge of the cutting material.