Characteristic orientation relationships in nanoscale Al-AlCu Eutectic

Wang, S.J.; Liu, Guisen; Wang, Jyhpyng; Misra, Amit

doi:10.1016/j.matchar.2018.05.037

Cited by 38 publications

(19 citation statements)

References 46 publications

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“…The eutectic with its highly ordered pattern can exhibit outstanding mechanical properties since its microstructure acts as natural or in situ composite [ 45 , 46 ]. For this reason, eutectic structures are explored in multi-principle component alloys (MPCAs) with yield strength and inter-lamellar spacing, λ, obeying a Hall-Petch-type relationship with either a λ −1 or λ −1/2 relationship [ 47 ].…”

Section: Discussionmentioning

confidence: 99%

On the Al–Al11Ce3 Eutectic Transformation in Aluminum–Cerium Binary Alloys

Czerwiński

Amirkhiz

2020

Materials

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The L ↔ Al + Al11Ce3 technologically important eutectic transformation in Al–Ce binary alloys, containing from 5 to 20 wt.% Ce and ranging from hypo- to hypereutectic compositions, was examined along with the microstructure and properties of its solidified product. A combination of thermal analysis and metallography determined the coordinates of the eutectic point at 644.5 ± 0.6 °C and 10.6 wt.% Ce, clarifying the existing literature ambiguity. Despite the high entropy of melting of the Al11Ce3 phase, in hypoeutectic alloys the eutectic was dominated by the regular morphology of periodically arranged lamellae, typical for non-faceted systems. In the lamellar eutectic, however, the faceting of Al11Ce3 was identified at the atomic scale. In contrast, for hypereutectic compositions, the Al11Ce3 eutectic phase exhibited complex morphology, influenced by the proeutectic Al11Ce3 phase. The Al11Ce3 eutectic phase lost its coherency with Al; it was deduced that a partial coherency was present only at early stages of lamellae growth. The orientation relationships between the Al11Ce3 and Al in the eutectic structure, leading to partial coherency, were determined to be Al ║ Al11Ce3 with Al ║ Al11Ce3 and Al ║ Al11Ce3 with Al ║ Al11Ce3. The Al11Ce3 phase with a hardness of 350 HV and Al matrix having 35 HV in their eutectic arrangement formed in situ composite, with the former playing a role of reinforcement. However, the coarse and mostly incoherent Al11Ce3 eutectic phase provided limited strengthening and the Al–Ce alloy consisting of 100% eutectic reached at room temperature a yield stress of just about 70 MPa.

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Section: Discussionmentioning

confidence: 99%

On the Al–Al11Ce3 Eutectic Transformation in Aluminum–Cerium Binary Alloys

Czerwiński

Amirkhiz

2020

Materials

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“…Other factors representing the degree of resemblance of the atomic arrangements in the coincident planes (lattice misfit, chemical order) have also been considered as parameters on which the interfacial energy of an interphase boundary may finely depend at equilibrium (see, e.g., Refs. [10], [20], and references therein). Here, we guided our analysis by focussing on the observed microstructures -essentially, the growth direction of the lamellae.…”

Section: Crystal Orientationmentioning

confidence: 99%

“…This is the case for the dependence of eutectic solidification microstructures on the orientation of the crystals with respect to each other and the solidification direction [9,10]. This crystalorientation effect has been extensively documented in experimental studies involving the bulk solidification of binary eutectics that grow with (special) crystal orientation relationships in the solid, in particular the Al-Al 2 Cu system [10,11,12,13,14,15,16,17,18,19,20]. Fundamental aspects of the problem have been addressed recently.…”

Section: Introductionmentioning

confidence: 99%

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Locked-lamellar eutectic growth in thin Al-Al2Cu samples: In situ directional solidification and crystal orientation analysis

Bottin-Rousseau

Medjkoune

Senninger

et al. 2021

Journal of Crystal Growth

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We investigated the directional-solidification dynamics of slightly hypoeutectic Al-Al 2 Cu alloys in thin samples. Our goal was to establish a link between the growth of locked, tilted-lamellar patterns and the crystal orientation relationship (OR) between the Al-rich solid solution α and the Al 2 Cu intermetallic θ, as well as to gain information on the OR-dependent anisotropy of the surface energy γ of the α-θ interphase boundaries. Thin Al-Al 2 Cu films of thickness of 13 ± 2 µm were prepared by plasma sputtering. During solidification at pulling velocities between 0.05 and 0.5 µms −1 , the coupled-growth front was observed in situ with a long-distance optics. The growth of millimeter-sized eutectic grains was thus followed in real time during transient and steady-state regimes. The orientation of α and θ crystals was measured ex situ by x-ray diffraction and electron backscattering diffraction. In several eutectic grains, a {123} α plane and a {100} θ plane were found to be closely parallel to each other. These coincident planes define a new family of (type-C) ORs in the Al-Al 2 Cu eutectic, which are distinct from the prevailing ORs that have been previously identified in bulk samples. Crucially, the inclination of the lamellae was systematically close to that of a {100} θ lattice plane, which therefore corresponds to a deep γ minimum in eutectic grains with a type-C OR, or a neighbor one. We initiated a discussion on the selection of the OR, the formation of "stray" eutectic grains, and the lamellar-growth dynamics at eutectic-grain boundaries.

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“…Like Al 3 Ti, the introduction of Ca induced the formation of Al 2 Cu in inner grain, which increased nucleation sites and promoted the precipitation of primary α-Al. Wang et al [28] investigated that the crystallographic orientation relationships between α-Al and Al 2 Cu was {211}Al 2 Cu||{111} Al and <120>Al 2 Cu||<110>Al. This indicated the formation of Al 2 Cu provided driving force for α-Al nucleation [29] .…”

Section: Modification Of Eutecticmentioning

confidence: 99%

Effect of Ca addition on solidification microstructure of hypoeutectic Al-Si casting alloys

et al. 2019

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The effect of Ca addition on the solidification microstructure of hypoeutectic Al-Si casting alloys was investigated using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) methods with particular attention focused on the change of morphologies of primary α-Al and eutectic silicon. Meanwhile, solute distribution in solid-liquid was simulated according to Scheil-Gulliver law. Results showed that primary α-Al and eutectic silicon were refined as Ca content increased because of the variation of the solute concentration in liquid. The addition of Ca increased the nucleation sites like Al 3 Ti or Al 2 Cu to promote the nucleation of primary α-Al. Affected by modification effect of Ca, the shape of eutectic silicon changed from flake to fibrous structure. In addition, coarse plate Ca-rich phases could be found along the grain boundary with high Ca content.

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Characteristic orientation relationships in nanoscale Al-AlCu Eutectic

Cited by 38 publications

References 46 publications

On the Al–Al11Ce3 Eutectic Transformation in Aluminum–Cerium Binary Alloys

On the Al–Al11Ce3 Eutectic Transformation in Aluminum–Cerium Binary Alloys

Locked-lamellar eutectic growth in thin Al-Al2Cu samples: In situ directional solidification and crystal orientation analysis

Effect of Ca addition on solidification microstructure of hypoeutectic Al-Si casting alloys

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