INFLUENCE OF MELTING TEMPERATURE AND TIME ON THE OXYGEN CONTENT IN TiAlNb ALLOYS

0440401 - ÚFM 2015 RIV CZ eng C - Conference Paper (international conference)
Barták, Tomáš - Zemčík, L. - Dlouhý, Antonín
INFLUENCE OF MELTING TEMPERATURE AND TIME ON THE OXYGEN CONTENT IN TiAlNb ALLOYS.
METAL 2011: 20TH ANNIVERSARY INTERNATIONAL CONFERENCE ON METALLURGY AND MATERIALS. Ostrava: TANGER LTD, 2011, s. 975-979. ISBN 978-80-87294-24-6.
[METAL 2011 - Anniversary International Conference on Metallurgy and Materials /20./. Brno (CZ), 18.05.2011-20.05.2011]
R&D Projects: GA ČR GA106/07/0762; GA ČR GA106/09/1913
Institutional research plan: CEZ:AV0Z20410507
Keywords : intermetallics * meeting * oxygen content
Subject RIV: JG - Metallurgy
http://www.metal2014.com/files/proceedings/metal_11/lists/papers/1021.pdf

The present study investigates a cost-effective melting of TiAlNb intermetallics in a stable yttrium oxide refractory. We identify mechanisms that mainly contribute to the oxygen pick-up during melting. Systematic microstructural and chemical analysis provided evidence that erosion and dissolution of crucible wall are key factors of the process. Experiments were performed using two Ti46Al7Nb alloys with a different initial content of oxygen. The alloys were re-melted in vacuum induction furnace inside U-shaped yttria crucibles. The experiments involved three different temperatures in combination with melting times spanning from 300 to 1800 s. The oxygen content of re-melted and solidified alloys was assessed by means of inert gas fusion technique. Results of the chemical analysis provided clear evidence that the stability of the refractory wall in contact with the molten alloy and its rate of dissolution depend mainly on melting temperature. These results are further supported by microstructural observations that confirmed ever growing content of ceramic phases in the solidified intermetallic with increasing temperature of the melt. The work also contributed to the improved experimental methodology, in particular to temperature measurements of reactive melts.
Permanent Link: http://hdl.handle.net/11104/0243537