Cu atoms suppress misfit dislocations at the β″/Al interface in Al–Mg–Si alloys

Saito, Takeshi; Ehlers, F.J.H.; Lefebvre, W.; Hernández-Maldonado, David; Bjørge, Ruben; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Mørtsell, Eva Anne; Holmestad, Randi

doi:10.1016/j.scriptamat.2015.07.033

Cited by 41 publications

(25 citation statements)

References 25 publications

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“…For some precipitates (not shown), Cu-enriched columns could be seen at the precipitate interface. This has been observed previously, and has been proposed as a mechanism to suppress misfit dislocations [42]. Fig.…”

Section: Sped Data Analysissupporting

confidence: 77%

The evolution of precipitate crystal structures in an Al-Mg-Si(-Cu) alloy studied by a combined HAADF-STEM and SPED approach

Sunde

Marioara

Holmestad

2018

Materials Characterization

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This work presents a detailed investigation into the effect of a low Cu addition (0.01 at.%) on precipitation in an Al-0.80Mg-0.85Si alloy during ageing. The precipitate crystal structures were assessed by scanning transmission electron microscopy combined with a novel scanning precession electron diffraction approach, which includes machine learning. The combination of techniques enabled evaluation of the atomic arrangement within individual precipitates, as well as an improved estimate of precipitate phase fractions at each ageing condition, through analysis of a statistically significant number of precipitates. Based on the obtained results, the total amount of solute atoms locked inside precipitates could be approximated. It was shown that even with a Cu content close to impurity levels, the Al-Mg-Si system precipitation was significantly affected with overageing. The principal change was due to a gradually increasing phase fraction of the Cu-containing Q -phase, which eventually was seen to dominate the precipitate structures. The structural overtake could be explained based on a continuous formation of the thermally stable Q -phase, with Cu atomic columns incorporating less Cu than what could potentially be accommodated.

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Section: Sped Data Analysissupporting

confidence: 77%

The evolution of precipitate crystal structures in an Al-Mg-Si(-Cu) alloy studied by a combined HAADF-STEM and SPED approach

Sunde

Marioara

Holmestad

2018

Materials Characterization

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“…In this case, Cu is weakly enriching the Si3/Al sites in both bulk and {320} interface. [18,19] The weak Z-contrast at these sites (but higher than the Si columns contrast) suggests partial column occupancies. Type 2 comprises mixed precipitates (in the same needle as viewed along its length) of b¢¢ parts and disordered parts of mainly Cu-containing b¢ Cu [20] configurations.…”

Section: Resultsmentioning

confidence: 99%

The Correlation Between Intergranular Corrosion Resistance and Copper Content in the Precipitate Microstructure in an AA6005A Alloy

Marioara

Lervik

Grønvold

et al. 2018

Metall Mater Trans A

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A positive correlation is observed between the amount of Cu incorporated in hardening precipitates and intergranular corrosion resistance in an artificially aged Cu-containing 6005A alloy. Three mechanisms have been identified to increase Cu absorption in hardening precipitates: by increasing aging temperature, by pre-deformation, and by slow cooling from solution heat treatment. These findings demonstrate the possibility for development of new processing routes to produce Cu-containing Al-Mg-Si alloys with improved corrosion resistance.

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“…Density functional theory (DFT): (234,242,260,261,271,276,307,328,330,339,343,346,350,351,358,378,408).…”

Section: Theoretical Modelling / Data Analysis Techniquesmentioning

confidence: 99%

The Crystallography of Aluminum and Its Alloys

Nakashima

2019

Encyclopedia of Aluminum and Its Alloys

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This article begins with pure aluminum and a discussion of the form of the crystal structure and different unit cells that can be used to describe it. Measurements of the face-centered cubic lattice parameter and thermal expansion coefficient in pure aluminum are reviewed and parametrizations are given which allow the reader to evaluate them across the full range of temperatures where aluminum is a solid. A new concept called the “vacancy triangle” is introduced and demonstrated as an effective means for determining vacancy concentrations near the melting point of aluminum. The Debye–Waller factor, quantifying the thermal vibration of aluminum atoms in pure aluminum, is reviewed and parametrized over the full range of temperatures where aluminum is a solid. The nature of interatomic bonding and the history of its characterization in pure aluminum are reviewed with the unequivocal conclusion that it is purely tetrahedral in nature. The crystallography of aluminum alloys is then discussed in terms of all of the concepts covered for pure aluminum, using prominent alloy examples. The electron density domain theory of solid-state nucleation and precipitate growth is introduced and discussed as a new means of rationalizing phase transformations in alloys from a crystallographic point of view.

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Cu atoms suppress misfit dislocations at the β″/Al interface in Al–Mg–Si alloys

Cited by 41 publications

References 25 publications

The evolution of precipitate crystal structures in an Al-Mg-Si(-Cu) alloy studied by a combined HAADF-STEM and SPED approach

The evolution of precipitate crystal structures in an Al-Mg-Si(-Cu) alloy studied by a combined HAADF-STEM and SPED approach

The Correlation Between Intergranular Corrosion Resistance and Copper Content in the Precipitate Microstructure in an AA6005A Alloy

The Crystallography of Aluminum and Its Alloys

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