Subbotina M. Tool sintered materials structure and properties improvement base on their transformations under microplastic deformation

Research object: processes energy dissipation, microplastic deformation and destruction of instrumental alloys during the local loading. Research subject: tool alloys reinforced with tungsten carbide and titanium car-bide manufactured via controlled vacuum hot-pressed technology. Research methods: optical metallography, raster electronic-microscopic analysis, x-ray phase analysis, three-point bend testing, hardness measuring, instrumental indentation. The dissertation highlighted the important scientific and technical task of deepig-ing our knowledge about the sintered tool alloys wear and destruction. New alloys with titanium carbide and structural metastable bind Ti-Ni/Ni-Fe were developed. The temperature interval for new alloys exploitation was determined. It was shown that exceeding of optimal working temperatures leads to intermetallic particles precipitation that cause decreasing of crack growth resistance in comparison with as-sintered materials. Cemented carbides capability to dissipate energy of applied plastic deformation was investigated. It was proved that cemented carbides are able to dissipate more than 80% of energy without cracking or fracturing. The comprehensive index was developed to allow tool materials to be quantitatively rated based on its physical -mechanical properties measured only via local indentation of specimens in laboratory environment. Recycled cemented carbide was developed from a hard-alloy scrap. The expected economic effect from recycling of scrap and secondary alloys production is made by a 78,5 million hrn. at a production of 150 t volume per year. The results were transmitted to LTD "Constantivoskiy plant of metallurgical equipment" for implementation.