TY  - JOUR
AU  - Ehlers, F. J. H.
AU  - Wenner, S.
AU  - Andersen, S. J.
AU  - Marioara, C. D.
AU  - Lefebvre, W.
AU  - Boothroyd, C. B.
AU  - Holmestad, R.
TI  - Phase stabilization principle and precipitate-host lattice influences for Al–Mg–Si–Cu alloy precipitates
JO  - Journal of materials science
VL  - 49
IS  - 18
SN  - 1573-4803
CY  - Dordrecht [u.a.]
PB  - Springer Science + Business Media B.V
M1  - FZJ-2015-04065
SP  - 6413 - 6426
PY  - 2014
AB  - In this work, we seek to elucidate a common stabilization principle for the metastable and equilibrium phases of the Al–Mg–Si–Cu alloy system, through combined experimental and theoretical studies. We examine the structurally known well-ordered Al–Mg–Si–Cu alloy metastable precipitates along with experimentally observed disordered phases, using high angle annular dark field scanning transmission electron microscopy. A small set of local geometries is found to fully explain all structures. Density functional theory based calculations have been carried out on a larger set of structures, all fully constructed by the same local geometries. The results reveal that experimentally reported and hypothetical Cu-free phases from the set are practically indistinguishable with regard to formation enthalpy and composition. This strongly supports a connection of the geometries with a bulk phase stabilization principle. We relate our findings to the Si network substructure commonly observed in all Mg–Al–Si(–Cu) metastable precipitates, showing how this structure can be regarded as a direct consequence of the local geometries. Further, our proposed phase stabilization principle clearly rests on the importance of metal-Si interactions. Close links to the Al–Mg–Si precipitation sequence are proposed.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000338348000026
DO  - DOI:10.1007/s10853-014-8371-4
UR  - https://juser.fz-juelich.de/record/201771
ER  -