ISSN:
1573-4889
Keywords:
Internal oxidation
;
nickel-aluminum alloys
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The formation and development of internal oxides in Ni-Al alloys containing 1–4 wt.% Al in Ni-NiO packs and in 1 atm oxygen at 800 to 1100°C have been studied. The internal oxide particles were relatively fine, closely spaced, and mainly acicular, although more granular near the surface. They were identified as Al2O3 at the advancing front, but NiAl2O4 at the surface and at a significant distance from that surface. Growth of internal oxide particles resulted in the development of significant compressive stresses in the internal oxide zone when formed in Ni-NiO packs. These stresses led to grainboundary sliding at the higher temperatures and extrusion of weak, internal oxide-denuded zones adjacent to alloy grain boundaries. At the lower temperatures, these stresses also resulted in significant preferential penetration of oxides down grain boundaries and sub-grain boundaries. Stress development and resulting phenomena were much less significant during oxidation in 1 atm oxygen because vacancies injected from the external NiO scale accommodated the volume increase during growth of internal oxide particles.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00662034
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