Influence of fiber alignment on creep in directionally solidified NiAl-10Mo in-situ composites

0398850 - ÚFM 2014 RIV GB eng J - Journal Article
Seemuller, C. - Heilmaier, M. - Haenschke, T. - Bei, H. - Dlouhý, Antonín - George, E.P.
Influence of fiber alignment on creep in directionally solidified NiAl-10Mo in-situ composites.
Intermetallics. Roč. 35, APR (2013), s. 110-115. ISSN 0966-9795. E-ISSN 1879-0216
R&D Projects: GA ČR(CZ) GA202/09/2073
Institutional support: RVO:68081723
Keywords : nickel aluminides * based on NiAl * creep (properties and mechanisms) * crystal growth * mechanical properties
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 2.119, year: 2013

A NiAl-Mo eutectic having a nominal composition of Ni-45Al-10Mo was directionally solidified in a floating-zone furnace at two different growth rates, 20 and 80 mm/h. At the slower growth rate, the Mo fibers in the composite are well-aligned with the growth direction, whereas at the higher growth rate cellular microstructures are observed. Creep testing at 900 degrees C showed that the minimum creep rate is much higher for cellular than for well-aligned structures. In the cellular case a "soft" cell boundary consisting primarily of binary NiAl surrounding "hard" eutectic cell interiors seems to facilitate cell boundary sliding and therefore results in low creep strength. A microstructure-based composite model is used to explain the effects of fiber alignment on creep resistance.
Permanent Link: http://hdl.handle.net/11104/0226234