Strengthening by the percolating intergranular eutectic in an HPDC Mg-Ce alloy

Zhang, Bao, Nagasekhar, Anumalasetty V., Tao, Xiaoma, Ouyang, Yifang, Caceres, Carlos H. and Easton, Mark (2014) Strengthening by the percolating intergranular eutectic in an HPDC Mg-Ce alloy. Materials Science and Engineering A, 599 204-211. doi:10.1016/j.msea.2014.01.074


Author Zhang, Bao
Nagasekhar, Anumalasetty V.
Tao, Xiaoma
Ouyang, Yifang
Caceres, Carlos H.
Easton, Mark
Title Strengthening by the percolating intergranular eutectic in an HPDC Mg-Ce alloy
Journal name Materials Science and Engineering A   Check publisher's open access policy
ISSN 0921-5093
1873-4936
Publication date 2014-04-02
Year available 2014
Sub-type Article (original research)
DOI 10.1016/j.msea.2014.01.074
Open Access Status Not yet assessed
Volume 599
Start page 204
End page 211
Total pages 8
Place of publication Lausanne, Switzerland
Publisher Elsevier
Language eng
Abstract Dual beam FIB tomography was used to create a 3D model of the percolating intergranular (alpha-Mg)-Mg12Ce eutectic in a Mg-0.51 at% Ce alloy and its tensile deformation behaviour assessed using finite elements. The eutectic itself was modelled as a fibre reinforced composite, with the elastic constants of the Mg12Ce intermetallic determined using a first principles approach. The 3D eutectic network exhibited a very low structural stiffness, akin to that of bending-dominated cellular structures. Such high compliance implies that the 3D structure may contribute to the alloy's strength while sustaining limited damage by cracking, hence extending the reinforcing without compromising the ductility, up to strains in excess of 1%. Elastic stretching of the 3D network adds similar to 25 MPa to the overall strength of the alloy at 0.2% offset strain, a value comparable to the strengthening expected from a similar volume fraction of dispersed (isolated) elastic particles. Flash anneal of the alloy to break up the spatial interconnection confirmed that the strengthening introduced by the eutectic stemed from the combination of network reinforcement and dispersion hardening. (c) 2014 Elsevier B.V. All rights reserved.
Formatted abstract
Dual beam FIB tomography was used to create a 3D model of the percolating intergranular (α-Mg)-Mg12Ce eutectic in a Mg-0.51 at% Ce alloy and its tensile deformation behaviour assessed using finite elements. The eutectic itself was modelled as a fibre reinforced composite, with the elastic constants of the Mg12Ce intermetallic determined using a first principles approach. The 3D eutectic network exhibited a very low structural stiffness, akin to that of bending-dominated cellular structures. Such high compliance implies that the 3D structure may contribute to the alloy[U+05F3]s strength while sustaining limited damage by cracking, hence extending the reinforcing without compromising the ductility, up to strains in excess of 1%. Elastic stretching of the 3D network adds ~25MPa to the overall strength of the alloy at 0.2% offset strain, a value comparable to the strengthening expected from a similar volume fraction of dispersed (isolated) elastic particles. Flash anneal of the alloy to break up the spatial interconnection confirmed that the strengthening introduced by the eutectic stemed from the combination of network reinforcement and dispersion hardening.
Keyword Mg alloys
FIB tomography
First-principles calculations
Finite element modelling
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mechanical & Mining Engineering Publications
Official 2015 Collection
 
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