Ti–Al material for high-temperature applications: Combustion synthesis from oxide raw materialsWednesday (28.09.2016) 15:15 - 15:30 Part of:
This work is focused on preparation of Nb-doped Ti–Al material by centrifugal SHS . TiO2 + Nb2O5 +Al mixtures (mix 1) were used as a metallothermic component, while CaO2 + Al + Ca mixtures (mix 2) were added as a booster. Green mixtures also contained some amount of functional additives.
Green mixtures became ignitable when the mix 2 content of green mixture (x) exceeded 10 wt %. Upon approaching to x = 100%, burning velocity U increased by a factor of ten and attained a value 14 cm/s. Variation in the Al content of green mixtures (between 20 and 40 wt %) had little or no influence on combustion characteristics but affected chemical composition of alloys and amount of nonmetal impurities and decreased the amount of oxygen in a target ingot. Combustion parameters and composition/structure of target Ti–Al materials also strongly depend on a magnitude of centrifugal acceleration. The latter also strongly suppresses the material splashing during vigorous combustion. The presence of functional additives (in amounts below 3 wt %) and a reducing agent (Ca) in mix 2 was found to decrease the amount of nonmetal impurities in a target product. Further details will be discussed at presentation.
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