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Transgranular liquation cracking of grains in the semi-solid state

Grain refinement via semi-solid deformation is desired to obtain superior mechanical properties of cast components. Using quantitative in situ synchrotron X-ray tomographic microscopy, we show an additional mechanism for the reduction of grain size, via liquation assisted transgranular cracking of s...

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Autores principales: Karagadde, S., Lee, P. D., Cai, B., Fife, J. L., Azeem, M. A., Kareh, K. M., Puncreobutr, C., Tsivoulas, D., Connolley, T., Atwood, R. C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Pub. Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4579839/
https://www.ncbi.nlm.nih.gov/pubmed/26353994
http://dx.doi.org/10.1038/ncomms9300
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author Karagadde, S.
Lee, P. D.
Cai, B.
Fife, J. L.
Azeem, M. A.
Kareh, K. M.
Puncreobutr, C.
Tsivoulas, D.
Connolley, T.
Atwood, R. C.
author_facet Karagadde, S.
Lee, P. D.
Cai, B.
Fife, J. L.
Azeem, M. A.
Kareh, K. M.
Puncreobutr, C.
Tsivoulas, D.
Connolley, T.
Atwood, R. C.
author_sort Karagadde, S.
collection PubMed
description Grain refinement via semi-solid deformation is desired to obtain superior mechanical properties of cast components. Using quantitative in situ synchrotron X-ray tomographic microscopy, we show an additional mechanism for the reduction of grain size, via liquation assisted transgranular cracking of semi-solid globular microstructures. Here we perform localized indentation of Al-15wt.%Cu globular microstructures, with an average grain size of ∼480 μm, at 555 °C (74% solid fraction). Although transgranular fracture has been observed in brittle materials, our results show transgranular fracture can also occur in metallic alloys in semi-solid state. This transgranular liquation cracking (TLC) occurs at very low contact stresses (between 1.1 and 38 MPa). With increasing strain, TLC continues to refine the size of the microstructure until the grain distribution reaches log-normal packing. The results demonstrate that this refinement, previously attributed to fragmentation of secondary arms by melt-shearing, is also controlled by an additional TLC mechanism.
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spelling pubmed-45798392015-10-01 Transgranular liquation cracking of grains in the semi-solid state Karagadde, S. Lee, P. D. Cai, B. Fife, J. L. Azeem, M. A. Kareh, K. M. Puncreobutr, C. Tsivoulas, D. Connolley, T. Atwood, R. C. Nat Commun Article Grain refinement via semi-solid deformation is desired to obtain superior mechanical properties of cast components. Using quantitative in situ synchrotron X-ray tomographic microscopy, we show an additional mechanism for the reduction of grain size, via liquation assisted transgranular cracking of semi-solid globular microstructures. Here we perform localized indentation of Al-15wt.%Cu globular microstructures, with an average grain size of ∼480 μm, at 555 °C (74% solid fraction). Although transgranular fracture has been observed in brittle materials, our results show transgranular fracture can also occur in metallic alloys in semi-solid state. This transgranular liquation cracking (TLC) occurs at very low contact stresses (between 1.1 and 38 MPa). With increasing strain, TLC continues to refine the size of the microstructure until the grain distribution reaches log-normal packing. The results demonstrate that this refinement, previously attributed to fragmentation of secondary arms by melt-shearing, is also controlled by an additional TLC mechanism. Nature Pub. Group 2015-09-10 /pmc/articles/PMC4579839/ /pubmed/26353994 http://dx.doi.org/10.1038/ncomms9300 Text en Copyright © 2015, Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved. http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Karagadde, S.
Lee, P. D.
Cai, B.
Fife, J. L.
Azeem, M. A.
Kareh, K. M.
Puncreobutr, C.
Tsivoulas, D.
Connolley, T.
Atwood, R. C.
Transgranular liquation cracking of grains in the semi-solid state
title Transgranular liquation cracking of grains in the semi-solid state
title_full Transgranular liquation cracking of grains in the semi-solid state
title_fullStr Transgranular liquation cracking of grains in the semi-solid state
title_full_unstemmed Transgranular liquation cracking of grains in the semi-solid state
title_short Transgranular liquation cracking of grains in the semi-solid state
title_sort transgranular liquation cracking of grains in the semi-solid state
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4579839/
https://www.ncbi.nlm.nih.gov/pubmed/26353994
http://dx.doi.org/10.1038/ncomms9300
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