Goltvyanytsya V. Development and using of titanium aluminum alloys for castings and coatings.

The aim of thesis was to create new advanced alloys with high temperature strength and thermal stability by their microalloying with rare earth metals and boron. Rational concentrations of yttrium and scandium in alloys of binary system Ti-Al, which permitted to create fine-grained microstructure and improve heat-resistant properties of the castings were determined. Reliable relationships between the content of gadolinium, scandium, yttrium, boron and structural components as well as physical-mechanical properties of the alloy Ti-36Al were established. Adding boron leads to the formation on the grain boundaries of small boride eutectic inclusions. Yttrium promotes the formation of compounds AlxY which resultes in the increase of the heat resistance of the base alloy. Gadolinium leads to the formation of non-metallic inclusions of spinel-type Gd2TiO5, which improves heat-resistant properties. Scandium in the amount of 0,1 wt. % increases the heat resistance and oxidation resistance of the alloy. Manufacturing application of research results will provide an estimated annual economic impact of UAH 47,7 thousand.