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National university of Shipbuilding, Mykolayiv Национальный университет кораблестроения, г. Николаев abstract. The optimal compositions and application techniques of wear-resistant alloys on platforms of turbine blades are discussed. It is demonstrated that the serious problems arise when choosing the necessary alloying materials despite the apparent variety of them. Such a choice is significantly complicated by the lack of quantitative characteristics of wear-resistance of widely used alloying materials and basic heat-resistant alloys. Consequently, the aim of the study was to determine the quantitative comparative characteristics of wear-resistance of the ЧС88У-ВИ casting heat-resistant nickel alloy and the Х30Н50Ю5Т2 stellite at peak temperatures of gas turbine engines exploitation in the conditions most closely resembling the actual ones. It is established that the ЧС88У-ВИ alloy in the conditions of high temperature tests (~ 1150 ºС) which are close to the solution temperatures of the γ′-phase demonstrates the considerably higher resistance than the Х30Н50Ю5Т2 stellite.

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Abstract. The new technologies of the diffusion vacuum welding (DVW) of aluminum alloys and titanium alloys have been considered. The aim of the paper is to study the special features of the processes of the formation of the structure and phases in the diffusion vacuum welding of an aluminum alloy with a titanium alloy, as well as the establishment of scientific foundations of obtaining welded joints by optimizing their structure and the phase composition. For the study of diffusion and recrystallization processes at the DVW, the specimens of AMg6 and WTi6 were welded without the AD1 interlayer and with its application. The metallographic studies were performed using an Auger microprobe equipped with an energy dispersive X-ray spectrometer of the INCA system on the sections of welded joints produced by ion etching. Due to the negative impact of magnesium, it is not possible to obtain a welded joint of the WTi6 titanium alloy with the AMg6 aluminum alloy without the aluminum interlayer. The initial AMg6 structure of the banded type is converted into grains of different sizes and shapes in the process of welding. At the area of the joint with the interlayer in the AMg6 alloy they have more equiaxed shape and smaller dimensions. In the AD1 alloy, there are oxide type globular inclusions of the production origin. The structure of the WTi6 titanium alloy does not change during the welding process and consists of the primary grains elongated along the rolled metal of the predominant form factor 2. The secondary structure is the α-phase plates with layers of the β-phase along the boundaries of the plates and primary grains. The results of the study are of interest in making products for the aviation and space industries. They are to meet the stringent requirements for preservation of the initial size of the details, which is only possible if there are no notable deformations. The determined regularities allowed developing the welding technology to obtain high-quality welded joints using the diffusion vacuum welding. The number of areas with defects is no more than 5 % of the total area of the joint, where the intermetallic compounds are not formed at the junction of the interlayer and the titanium alloy.