The paper presents the method of electron beam vacuum evaporation and condensation for the most promising technologies of manufacturing modern composite materials, used in welding and switching equipment. This method currently is one of the components of the technological process of producing thin (up to 5 mm) films for radio engineering, microelectronics, computer engineering, etc., as well as thick (more than 5 mm) films-condensates widely applied as effective protective and wear-resistant coatings. Described are the results of scientific and production activity on introduction into industry of technologies of deposition of thick films based on copper and refractory metals (molybdenum, tungsten, chromium) with additives of REM and other metals (yttrium, zirconium) on the surface of electric contacts and electrodes. Proceeding from the results of trials performed in more than 54 enterprises of Ukraine, Russia, Georgia, Rumania, Poland and PRC it was established that the developed materials are not inferior to silver-containing powder compositions in terms of serviceability, while being approximately 3 times less expensive than the latter. 57 Ref., 1 Table, 4 Figures.

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The structure, hardness, strength, and plasticity of a laminated composite nanomaterial of the copper-zirconium-yttrium-molybdenum system obtained by electron-beam evaporation and layered vapor condensation over a temperature range of 290-1070 K are studied. Correlation between the hardness and strength of the composite was established.Introduction. Nowadays laminated composites based on copper, molybdenum, and rare earth metals are used more and more extensively as electrocontact materials for heavy-duty switching devices. These materials are formed by high-rate vacuum evaporation and condensation of a mixed vapor flow on a rotating disk. Such a composition determines their unique physicomechanical and operating properties. Dispersion-hardened MDK composites of the Cu-Zr-Y-Mo system (TU U 20113410.001-98) with molybdenum contents from 2.5-5.0 to 8.1-12.0 wt% and the total zirconium and yttrium contents no more than 0.8 wt% are currently manufactured at Gekont Science&Technology Company (Ukraine) [1][2][3][4].In operation, the materials of contacting pairs in high-current switching devices are subjected not only to corrosion and electrical erosion but also to mechanical loads at elevated temperatures. Therefore, studies on their mechanical properties over operating temperature ranges are of definite scientific and practical interest.The present publication covers data on experimental investigations of the structure, strength, hardness, and plasticity of the most promising laminated composite MDK-3 with a molybdenum content of 11 3 0 2 . . ± wt% over a temperature range of 290-1070 K.Test Methods. The structure of the composite material was investigated by optical and scanning electron microscopy. Mechanical characteristics were determined from the results of tensile tests in vacuum on standard sheet specimens with a 15-mm calculated test portion using a 1246-P unit [5] according to . The specimens were cut from the prepared composite 0.9-1.4 mm thick as-received (after vacuum annealing at 1170 K for 3 h). The tests were performed on 3-6 specimens at 100 K intervals. Their deformation rate was 2 mm/min, which corresponded to a relative strain rate of~. 2 2 10 3 1 ⋅ − − s . During the tests deformation diagrams were recorded to determine the yield strength σ 0 2 . , the ultimate strength σ u , the elongation δ, and the uniform elongation δ u . Moreover, the reduction of cross-sectional area ψ was evaluated.Hardness was estimated by Vickers indentation. The pyramidal point was made of a synthetic corundum single crystal. Indentation loads were 10 N. The tests were carried out in vacuum at a pressure no more than 0.7 MPa on a UVT-2 unit [7] according to DSTU 2434-94 [8].Experimental data were statistically processed. The average sample value (mathematical expectation) x, the sample standard deviation S, the coefficient of variation w, and the confidence limits Δx for the mathematical expectation were calculated at a significance level of α = 0 05 . .

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