Precipitates in aluminium alloys

Andersen, Sigmund Jarle; Marioara, Calin Daniel; Friis, Jesper; Wenner, Sigurd; Holmestad, Randi

doi:10.1080/23746149.2018.1479984

Cited by 59 publications

(52 citation statements)

References 86 publications

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“…The η 1 internal structure was found to incorporate some different arrangements of atomic structures, deviating from the stacking of (0001) MgZn 2 structure planes [20]. Furthermore, a cross-section of needle-like precipitates along 〈112〉 Al which do not fall into any particular orientation relationship was observed to incorporate Mg 6 Zn 7 elongated hexagons [21]. Sub-unit cell of Mg 6 Zn 7 elongated hexagons is also present in the metastable h ′ phase [21].…”

Section: Introductionmentioning

confidence: 97%

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Characterisation of structural similarities of precipitates in Mg–Zn and Al–Zn–Mg alloys systems

Bendo

Maeda

Matsuda

et al. 2019

Philosophical Magazine

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High angle annular dark field scanning transmission electron microscopy has been employed to observe precipitate structures in Al-Zn-Mg and Mg-Zn alloys. h 1 precipitate structures in Al-Zn-Mg are commonly formed by MgZn 2 Penrose bricks, but also frequently observed to incorporate Mg 6 Zn 7 elongated hexagons via two different modes. Tilings of MgZn 2 and Mg 6 Zn 7 building blocks in both b ′ 1 in Mg-Zn and h 1 in Al-Zn-Mg alloys, create overall patterns which deviate from the chemical and structural configuration of solely monoclinic Mg 4 Zn 7 or MgZn 2 unit cells. Precipitate morphologies were found to be correlated to their internal sub-unit cell arrangements, especially to Mg 6 Zn 7 elongated hexagons. Systematic or random arrangements of Mg 6 Zn 7 elongated hexagons inside precipitates and therefore compositional and structural patterns, were found to be strongly related to the aspect ratio of the precipitates and altering of the precipitate/matrix interfaces.

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Section: Introductionmentioning

confidence: 97%

“…Furthermore, a cross-section of needle-like precipitates along 〈112〉 Al which do not fall into any particular orientation relationship was observed to incorporate Mg 6 Zn 7 elongated hexagons [21]. Sub-unit cell of Mg 6 Zn 7 elongated hexagons is also present in the metastable h ′ phase [21].…”

Section: Introductionmentioning

confidence: 97%

Characterisation of structural similarities of precipitates in Mg–Zn and Al–Zn–Mg alloys systems

Bendo

Maeda

Matsuda

et al. 2019

Philosophical Magazine

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“…A schematic representation of the precipitation process is shown in Figure 1 . Maximum strength characteristics after hardening are obtained in the region of coherent precipitates θ” and at the beginning of the precipitation of the partially coherent phase θ’ [ 15 , 16 , 17 , 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Study of Natural and Artificial Aging on AlSi9Cu3 Alloy at Different Ratios of Returnable Material in the Batch

et al. 2020

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Aluminum alloys currently play an important role in the production of castings in various industries, where important requirements include low component weight, reduction of the environmental impact and, above all, reduction of production costs of castings. One way to achieve these goals is to use recycled aluminum alloys. The effect of natural and artificial aging of AlSi9Cu3 alloy with different ratios of returnable material in the batch was evaluated by a combination of optical, scanning, transmission microscope and mechanical tests. An increase in the returnable material in the batch above 70% resulted in failure to achieve the minimum value required by the standard for tensile strength and ductility. The application of artificial aging had a positive effect on the microstructure and thus on the mechanical properties of experimental alloys. By analyzing the results from TEM, it can be stated that in the given cases there is a reduced efficiency of θ’-Al2Cu precipitate formation with an increase of the returnable material in the batch and in comparison with artificial aging, which is manifested by low mechanical properties.

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“…There is a growing body of interest that recognises the importance of aluminium processing and its strengthening procedures. The standard features of aluminium can be advanced through some heat treatments, such as age-hardening (Oguz, 1990;Jordan, 2016;Andersen et al, 2018). On the other hand, aluminium alloys are very sensitive to their processing conditions (Nascente et al, 2002) in spite of the fact that these hardening processes provide advantageous properties through generating secondary phases, i.e.…”

Section: Introductionmentioning

confidence: 99%

Development of laser welding of high strength aluminium alloy 2024-T4 with controlled thermal cycle

et al. 2020

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An innovative process design, to avoid thermal degradation during autogenous fusion welding of high strength AA 2024-T4 alloy, based on laser beam welding, is being developed. A series of instrumented laser welds in 2 mm thick AA 2024-T4 alloys were made with different processing conditions resulting in different thermal profiles and cooling rates. The welds were examined under SEM, TEM and LOM, and subjected to micro-hardness examination. This allowed us to understand the influence of cooling rate, peak temperature, and thermal cycle on the growth of precipitates, and related degradation in the weld and heat affected area, evident as softening. Although laser beam welding allows significant reduction of heat input, and higher cooling rates, as compared to other high heat input welding processes, this was found insufficient to completely supress coarsening of precipitate in HAZ. To understand the required range of thermal cycles, additional dilatometry tests were carried out using the same base material to understand the time-temperature relationship of precipitate formation. The results were used to design a novel laser welding process with enhanced cooling, such as with copper backing bar and cryogenic cooling.

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Precipitates in aluminium alloys

Cited by 59 publications

References 86 publications

Characterisation of structural similarities of precipitates in Mg–Zn and Al–Zn–Mg alloys systems

Characterisation of structural similarities of precipitates in Mg–Zn and Al–Zn–Mg alloys systems

Study of Natural and Artificial Aging on AlSi9Cu3 Alloy at Different Ratios of Returnable Material in the Batch

Development of laser welding of high strength aluminium alloy 2024-T4 with controlled thermal cycle

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