Kovalenko T. Improving of mechanical properties of submicrocrystalline titanium alloys by means of deformation and heat treatment.

The research subject is the process of structure formation and the relationship between the structure and the properties of submicrocrystalline alpha- and (alpha+Beta) titanium alloys during straining and heat treatment. The research object is the structure and mechanical properties of (alpha+Beta) titanium alloys with a standard (microcrystalline) and experimental (submicrocrystalline) microstructure.The aim of the research is sophistication of the submicrocrystalline titanium alloys structure in order to increase the mechanical properties by straining and heat treatment.The research methods of defining the chemistry of the alloys by using X-ray spectrum, chemical and energy dispersion methods. The structures and fractographs of the fracture surfaces in the alloys were studied using an optical, scanning and transmission microscopes. The mechanical properties were determined with standard practices. The results attained: it has been identified that formation of the submicrocrystalline structure by intensive plastic straining technique leads to 1.3 - times improvement in the strength of the titanium alloys, 180°С - decrease in recrystallisation temperature and 60°С - decrease in polymorphous transition. A chemical composition and special heat treatments as well as a lean production process for making titanium parts have been developed.Introduced at Zaporozhye Titanium and Magnesium Plant and at Motor Sich JSC. Area of application - aeroenginebuilding.