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Revealing the atomistic nature of dislocation-precipitate interactions in Al-Cu alloys
Published in Elsevier Ltd
2019
Volume: 797
   
Pages: 325 - 333
Abstract
Despite significant gains on understanding strengthening mechanisms in precipitate strengthened materials, such as aluminum alloys, there persists a sizeable gap in the atomistic understanding of how different precipitate types and their morphology along with dislocation character affects the hardening mechanisms. Toward this, the paper examines nature of precipitation strengthening behavior observed in the Al-Cu alloys using atomistic simulations. Specifically, the critical resolved shear stress is quantified across a wide range of dislocation-precipitate interactions scenarios for both θ′ and θ phase of Al2Cu. Overall, the simulations reveal that the dislocation character (edge or screw) plays a key role in determining the predominant hardening mechanism (shearing vs. Orowan looping) employed to overcome the θ′ Al2Cu precipitate. Furthermore, the critical shear stress and mechanism to overcome the precipitate is sensitivity to the position of the glide plane with respect to the precipitate and its orientation. Interestingly in our findings, the θ Al2Cu precipitate conventionally regarded as un-shearable particle was overcome by shear cutting mechanism for small equivalent precipitate radius, which agrees with recent TEM observations. These findings provide necessary information for the development of atomistically informed precipitate hardening models for the traditional continuum scale modeling efforts. © 2019 Elsevier B.V.
About the journal
JournalData powered by TypesetJournal of Alloys and Compounds
PublisherData powered by TypesetElsevier Ltd
ISSN09258388
Open AccessNo
Concepts (16)
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    Age hardening
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    Binary alloys
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    Copper alloys
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    Dislocations (crystals)
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    Hardening
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    Precipitation (chemical)
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    Shear stress
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    ATOMISTIC
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    ATOMISTIC SIMULATIONS
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    Critical resolved shear stress
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    CRITICAL SHEAR STRESS
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    DISLOCATION CHARACTERS
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    PRECIPITATE HARDENING
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    PRECIPITATION STRENGTHENING
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    STRENGTHENING MECHANISMS
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    Aluminum alloys