Browsing by Author "Vadchenko, S. G."
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Item Microstructure and mechanical properties of gamma TiAl based alloys produced by combustion synthesis + compaction route(2008-11) Agote, I.; Coleto, J.; Gutiérrez, M.; Sargsyan, A.; García de Cortazar, M.; Lagos, M. A.; Borovinskaya, I. P.; Sytschev, A. E.; Kvanin, V. L.; Balikhina, N. T.; Vadchenko, S. G.; Lucas, K.; Wisbey, A.; Pambaguian, L.; EXTREMAT; Mercado; SG; CIRMETALMicrostructure and mechanical properties of γ-TiAl alloy with the chemical composition Ti-48Al-2Cr-2Nb (at.%) have been investigated. The alloy was prepared in one step using a combustion synthesis + compaction process, where the synthesis and the shaping take place at the same time. Two different combustion routes were used: forced self-propagating high-temperature synthesis + compaction (FSHS + C) and thermal explosion + compaction (TE + C). Fully lamellar microstructure was obtained in both processing routes after the appropriate homogenisation thermal treatment. Nevertheless, TE + C route showed coarser lamellar colonies. A remarkable oxygen content reduction was achieved in samples synthesised by FSHS + C route. Tensile properties (especially UTS) were found to be in the same range as other alloys obtained by conventional processing routes, however, low ductility was achieved. Good creep and fatigue properties were obtained. All fracture surfaces showed a brittle fracture mechanism. Finally, it was found out that the studied processing routes showed promising results as an alternative manufacturing technology for γ-TiAl based alloys.Item Production of γ-TiAl based alloy by combustion synthesis + compaction route, characterization and application(2008) Agote, I.; Coleto, J.; Gutiérrez, M.; Sargsyan, A.; De Cortazar, M. García; Lagos, M. A.; Kvanin, V. L.; Balikhina, N. T.; Vadchenko, S. G.; Borovinskaya, I. P.; Sytschev, A. E.; Pambaguian, L.; EXTREMAT; Mercado; SG; CIRMETALSynthesis and densification of γ-TiAl alloy with nominal chemical composition Ti-48A1-2Cr-2Nb (at.%) have been investigated. The alloy is prepared in one step using a combustion synthesis + compaction process, where the synthesis and the shaping take place at the same time. Two different combustion routes are used: Forced Self-propagating High-temperature Synthesis + Compaction (FSHS + C) and Thermal Explosion + Compaction (TE + C). The optimal synthesis parameters such as ignition point, load application delay time, load value, load holding time, heating and cooling rates are determined. After the processing, the density of the samples was measured to be of about 99 % of the theoretical value. It is shown that the oxygen content can be controlled during the processing and products with the same or lower oxygen content than that in the original raw material can be obtained. Analysis of chemical composition and microstructure shows that a complete chemical homogenization, required phase composition, desired lamellar microstructure and relaxation of possible internal stresses require additional thermal treatment of samples prepared by both FSHS + C and TE + C processes.