Revealing the micromechanisms behind semi-solid metal deformation with time-resolved X-ray tomography
Author(s)
Kareh, KM
Lee, PD
Atwood, RC
Connolley, T
Gourlay, CM
Type
Journal Article
Abstract
The behaviour of granular solid–liquid mixtures is key when deforming a wide range of materials from cornstarch slurries to soils, rock and magma flows. Here we demonstrate that treating semi-solid alloys as a granular fluid is critical to understanding flow behaviour and defect formation during casting. Using synchrotron X-ray tomography, we directly measure the discrete grain response during uniaxial compression. We show that the stress–strain response at 64–93% solid is due to the shear-induced dilation of discrete rearranging grains. This leads to the counter-intuitive result that, in unfed samples, compression can open internal pores and draw the free surface into the liquid, resulting in cracking. A soil mechanics approach shows that, irrespective of initial solid fraction, the solid packing density moves towards a constant value during deformation, consistent with the existence of a critical state in mushy alloys analogous to soils.
Date Issued
2014-07-01
Date Acceptance
2014-06-19
Citation
Nature Communications, 2014, 5, pp.1-7
ISSN
2041-1723
Publisher
Nature Research
Start Page
1
End Page
7
Journal / Book Title
Nature Communications
Volume
5
Copyright Statement
© 2014 Macmillan Publishers Limited. All rights reserved. his 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/
License URL
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000340623400009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
EP/K026763/1
EP/M002241/1
Subjects
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
IN-SITU
RHEOLOGICAL BEHAVIOR
MECHANICAL-BEHAVIOR
GRANULAR MODEL
MUSHY ZONE
ALLOYS
SOLIDIFICATION
COALESCENCE
SUSPENSIONS
DILATANCY
Publication Status
Published
Article Number
ARTN 4464
Date Publish Online
2014-07-18