Creep in NiAl-Mo Eutectics

0376019 - ÚFM 2012 RIV CZ eng C - Conference Paper (international conference)
Dudová, Marie - Barták, Tomáš - Kuchařová, Květa - Dlouhý, Antonín
Creep in NiAl-Mo Eutectics.
METAL 2011 Conference Proceedings. Ostrava: TANGER, spol. s r.o., 2011, paper no. 926. ISBN 978-80-87294-22-2.
[METAL 2011 /20./. Brno (CZ), 18.05.2011-20.05.2011]
R&D Projects: GA ČR GA202/09/2073
Institutional research plan: CEZ:AV0Z20410507
Keywords : creep * eutectics * in-situ composites
Subject RIV: JG - Metallurgy

We report on creep in NiAl-Mo ternary eutectic and NiAl intermetallic, having respective nominal compositions Ni-45.5Al-9Mo and Ni-45.2Al (at.%). These alloys were directionally solidified in a high-temperature optical floating zone furnace. The eutectic alloy exhibited a well-aligned rod-like microstructure, consisting of NiAl matrix and 14% (by volume) continuous Mo-fibres oriented along a [001]-crystal growth direction. Cylindrical [001]-oriented specimens were loaded in compression at temperatures in a range 1073 – 1173 K. Formidable strengthening by regularly distributed fine fibres (typical diameter, 400 nm) was observed which resulted in minimum creep rates of the NiAl-Mo eutectic that were seven orders of magnitude lower than the corresponding minimum creep rates of the NiAl matrix. Preliminary microstructural investigations suggested that the strengthening effect is due to an interaction between Mo fibres and subgrain boundaries that form in the course of creep. This interaction leads to an increase of dislocation density in the vicinity of fibres and to an efficient redistribution of stresses in the microstructure.
Permanent Link: http://hdl.handle.net/11104/0006937