γ′ Precipitation and Growth Kinetics in Mechanically Alloyed Ni–Al

The precipitation and growth kinetics of γ′ precipitates, which are strengthening factors in Ni-base oxide dispersion strengthened (ODS) superalloys, were investigated. The cuboidal-type γ′ precipitates are formed in conventional arc-melted Ni–Al alloys, whereas spherical-type precipitates are forme...

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Bibliographic Details
Published in:Advances in materials science and engineering 2011-01, Vol.2011 (2011), p.1-7
Main Authors: Ukai, Shigeharu, Tang, QingXin, Hayashi, Shigenari, Minami, Akinobu
Format: Article
Language:English
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Summary:The precipitation and growth kinetics of γ′ precipitates, which are strengthening factors in Ni-base oxide dispersion strengthened (ODS) superalloys, were investigated. The cuboidal-type γ′ precipitates are formed in conventional arc-melted Ni–Al alloys, whereas spherical-type precipitates are formed in the mechanically alloyed (MAed) specimens. The morphology is controlled by a lattice misfit between the γ′ precipitates and the matrix at the aging temperature of 800°C. The growth kinetics of the γ′ precipitates can be followed by Ostwald ripening. The Arrhenius plot yielded a lower activation energy for the solute atom diffusion in MAed specimens, which is attributed to their high dislocation density and nanosized grains.
ISSN:1687-8434
1687-8442
DOI:10.1155/2011/137387