Browsing by Author "Kharatyan, S. L."
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Item Fabrication of Cu-W nanocomposites by integration of self-propagating high-temperature synthesis and hot explosive consolidation technologies(2018) Aydinyan, S. V.; Kirakosyan, H. V.; Zakaryan, M. K.; Abovyan, L. S.; Kharatyan, S. L.; Peikrishvili, A.; Mamniashvili, G.; Godibadze, B.; Chagelishvili, E. Sh; Lesuer, D. R.; Gutierrez, M.; SGManufacturing W-Cu composite nanopowders was performed via joint reduction of CuO and WO3 oxides with various ratios (W:Cu = 2:1, 1:1, 1:3, 1:13.5) using combined Mg–C reducer. Combustion synthesis was used to synthesize homogeneous composite powders of W-Cu and hot explosive consolidation (HEC) technique was utilized to fabricate dense compacts from ultrafine structured W-Cu powders. Compact samples obtained from nanometer sized SHS powders demonstrated weak relation between the susceptibility and the applied magnetic field in comparison with the W and Cu containing micrometer grain size of metals. The density, microstructural uniformity and mechanical properties of SHS&HEC prepared samples were also evaluated. Internal friction (Q-1) and Young modulus (E) of fabricated composites studied for all samples indicated that the temperature 1000 °С is optimal for full annealing of microscopic defects of structure and internal stresses. Improved characteristics for Young modulus and internal friction were obtained for the W:Cu = 1:13.5 composite. According to microhardness measurement results, W-Cu nanopowders obtained by SHS method and compacted by HEC technology were characterized by enhanced (up to 85%) microhardness.Item Production of Ti/Tib master alloy by SHS process for the obtention Ti/Tib composites for the automotive industry(European Powder Metallurgy Association (EPMA), 2005) García de Cortazar, M.; Agote, I.; Coleto, J.; Gutiérrez, M.; Kharatyan, S. L.; Sargsyan, A. R.; CIRMETAL; EXTREMAT; Mercado; SGHigh technology transport sectors are looking for higher performance materials, competitive in terms of cost, lighter than conventional titanium alloys and recyclable, which could improve efficiency of several components and reduce fuel consumption through weight reduction. This work has been carried out in the framework of Growth NEWTIRAL project (Contract N°G5RD-CT01-00529) financially supported by the European Commission, which investigates the production of in situ Ti/TiB master alloy (with a high volume fraction of reinforcing phase) that is further melted together with titanium ingots. This way a composite with controlled TiB reinforcement volume fraction can be obtained via conventional casting route. This study focuses in the investigation of the production technique of the Ti/TiB master alloy, which is produce by SHS (Self Propagating High temperature Synthesis). This technique is a self-sustaining combustion process of any chemical compound that results in the formation of valuable condensed products. The SHS is based on the principle of maximum utilization of chemical energy of reacting substances (exothermicity) for obtaining inorganic compounds, materials, and items of various application purposes and also for organizing highly efficient technological processes. The obtained product is characterised using different techniques: XRD, SEM, and mechanical properties.