A model for co-clusters and their strengthening in Al-Cu-Mg based alloys
A model for co-clusters and their strengthening in Al-Cu-Mg based alloys
The prevailing theory of strengthening of metallic alloys incorporates the effects of solute atoms and stable or metastable second phases which act as obstacles to dislocation motion. Metastable second phases can be very small: precipitates as small as 10 atoms have been proposed. These small precipitates are effectively formed from a metastable solution through a solute clustering process. If the clusters formed involve two alloying elements, the term co-clusters is employed; the simplest form of a co-cluster is a dimer. 3D atom probe has allowed the identification of clusters as small as 10 atoms in alloys such as in maraging Fe-20Ni-1.8Mn-1.5Ti-0.59Al, Al-Zn-Mg(-Cu) and Al-Cu-Mg based alloys.
A theory for the thermodynamics of co-clusters in metallic alloys is presented; thus providing the theoretical basis for application in microstructure modelling software. The formulation uses interaction enthalpies combined with the configurational entropy and ussumes a regular solution. A model for the strengthening due to co-clusters is also derived. The model encompasses modulus hardening, chemical hardening and (short-) order strengthening. It is shown that in general (short-) order strengthening will be the main strengthening mechanism.
The model formulation is tested against an extensive amount of published and new data on the Al-Cu-Mg system and the Al-Zn-Mg system, and interaction enthalpies are determined. Both quantitative calorimetry data on the enthalpy change due to co-cluster formation and strengthening due to co-clusters is predicted well.
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
2011
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
Starink, M.J.
(2011)
A model for co-clusters and their strengthening in Al-Cu-Mg based alloys.
Thermec 2011, Quebec, Canada.
30 Jul - 04 Aug 2011.
Record type:
Conference or Workshop Item
(Other)
Abstract
The prevailing theory of strengthening of metallic alloys incorporates the effects of solute atoms and stable or metastable second phases which act as obstacles to dislocation motion. Metastable second phases can be very small: precipitates as small as 10 atoms have been proposed. These small precipitates are effectively formed from a metastable solution through a solute clustering process. If the clusters formed involve two alloying elements, the term co-clusters is employed; the simplest form of a co-cluster is a dimer. 3D atom probe has allowed the identification of clusters as small as 10 atoms in alloys such as in maraging Fe-20Ni-1.8Mn-1.5Ti-0.59Al, Al-Zn-Mg(-Cu) and Al-Cu-Mg based alloys.
A theory for the thermodynamics of co-clusters in metallic alloys is presented; thus providing the theoretical basis for application in microstructure modelling software. The formulation uses interaction enthalpies combined with the configurational entropy and ussumes a regular solution. A model for the strengthening due to co-clusters is also derived. The model encompasses modulus hardening, chemical hardening and (short-) order strengthening. It is shown that in general (short-) order strengthening will be the main strengthening mechanism.
The model formulation is tested against an extensive amount of published and new data on the Al-Cu-Mg system and the Al-Zn-Mg system, and interaction enthalpies are determined. Both quantitative calorimetry data on the enthalpy change due to co-cluster formation and strengthening due to co-clusters is predicted well.
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Published date: 2011
Venue - Dates:
Thermec 2011, Quebec, Canada, 2011-07-30 - 2011-08-04
Organisations:
Engineering Mats & Surface Engineerg Gp
Identifiers
Local EPrints ID: 373231
URI: http://eprints.soton.ac.uk/id/eprint/373231
PURE UUID: cc67a660-1781-4b6f-abdc-4670440fdc6b
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Date deposited: 13 Jan 2015 11:51
Last modified: 11 Dec 2021 05:50
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