Stabilization and strengthening of nanocrystalline copper by alloying with tantalum

Nanocrystalline Cu–Ta alloys belong to an emerging class of immiscible high-strength materials with a significant potential for high-temperature applications. Using molecular dynamics simulations with an angular-dependent interatomic potential, we study the effect of Ta on the resistance to grain gr...

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Bibliographic Details
Published in:Acta materialia 2012-03, Vol.60 (5), p.2158-2168
Main Authors: Frolov, T., Darling, K.A., Kecskes, L.J., Mishin, Y.
Format: Article
Language:English
Subjects:
Applied sciences
Exact sciences and technology
Grain growth
Metals. Metallurgy
Molecular dynamics
Nanocrystalline materials
Segregation
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Summary:Nanocrystalline Cu–Ta alloys belong to an emerging class of immiscible high-strength materials with a significant potential for high-temperature applications. Using molecular dynamics simulations with an angular-dependent interatomic potential, we study the effect of Ta on the resistance to grain growth and mechanical strength of nanocrystalline Cu–6.5at.% Ta alloys. Ta segregation at grain boundaries greatly increases structural stability and strength in comparison with pure copper and alloys with a uniform distribution of the same amount of Ta. At high temperatures, the segregated Ta atoms agglomerate and form a set of nanoclusters located at grain boundaries. These nanoclusters are capable of pinning grain boundaries and effectively preventing grain growth. It is suggested that the nanoclusters are precursors to the formation of larger Ta particles found in Cu–Ta alloys experimentally.
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2012.01.011