Tolochyn O. Feature of obtaining of ultrafine structure in WC–Co (Ni) system with the high content of a metal phase and development of materials with the increased mechanical properties.

The object is the tungsten carbides hard metals of the WC-Co(Ni) alloy system with high content, of binder from 20 to 50 wt.%. The aim is development of conditions of preparation of ultrafine structures in WC-Co(Ni) with high content of the metallic phase, investigation of the correlation between physico-chemical properties and structure, development and testing hard metals with high content of Co (Ni) which possess good mechanical properties. Methods are optical and scanning electron microscopy, chemical, powder X-ray analysis, Student's method, theories of the dispersed and grain-boundary strengthening. The way of improvement of quality of the hardmetals, based on powder consolidation in solid state and providing receiving hardmetals with ultrafine-grained structure and the minimal degree of carbide particles contact (contiguity) is offered. It allows to increase transverse rupture strength, fracture toughness, yield strenth at compression, and also to keep high enough level of hardness on alloys with the increased content of a binder. Densification in solid state by high-energy pressing of ultrathin mixtures of powders WC–Co and also mixtures of WC–Co (Ni) powders, where metal phase has been formed directly during heating WC powders and metal oxides was carried out. Approbation of new ultrafine VK20, VK30 and VK35, VK40 hardmetals on operations of cutting down and heading has shown increase in resistance of the tool more than 2 times in comparison with VK16, VK20, VK20K hardmetals.