Multiscale characterization of the nucleation and 3D structure of Al3Sc phases using electron microscopy and synchrotron X-ray tomography

Zhao, Yuliang; Zhang, Weiwen; Koe, Billy; Du, Weidong; Wang, Mengmeng; Wang, Weilin; Boller, Élodie; Rack, Alexander; Sun, Zhuo; Shu, Da; Sun, Baode; Mi, Jiawei

doi:10.1016/j.matchar.2020.110353

Cited by 20 publications

(5 citation statements)

References 35 publications

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“…Most Fe-rich phases in the Al-5Cu-1.5Fe-1Si alloy exhibit complex 3D spatially connected network structure and morphologies. Similar structures were found and reported in the Al-Fe-Si alloys containing Mn [21], Mg [12] and Cu [23] elements. This indicates that the initial Al-Fe phase morphologies formed at higher temperature has significant impact on the morphology of later developed Fe-rich phases.…”

Section: Discussionsupporting

confidence: 89%

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Characterization of the Convoluted 3D Intermetallic Phases in a Recycled Al Alloy by Synchrotron X-ray Tomography and Machine Learning

Qin

Guo

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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Fe-rich intermetallic phases in recycled Al alloys often exhibit complex and 3D convoluted structures and morphologies. They are the common detrimental intermetallic phases to the mechanical properties of recycled Al alloys. In this study, we used synchrotron X-ray tomography to study the true 3D morphologies of the Ferich phases, Al2Cu phases and casting defects in an as-cast Al-5Cu-1.5Fe-1Si alloy.Machine learning based image processing approach was used to recognize and segment the different phases in the 3D tomography image stacks. In the studied condition, the β-Al9Fe2Si2 and ω-Al7Cu2 are found to be the main Fe-rich intermetallic phases. The β-Al9Fe2Si2 phases exhibit a spatially connected 3D network structure and morphology which in turn control the 3D spatial distribution of the Al2Cu phases and the shrinkage cavities. The Al3Fe phases formed at the early stage of solidification affects to a large extent the structure and morphology of the subsequently formed Ferich intermetallic phases. The machine learning method has been demonstrated as a powerful tool for processing big datasets in multidimensional imaging-based materials characterization work.

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Section: Discussionsupporting

confidence: 89%

“…The synchrotron X-ray tomography experiments were carried out at the ID19 beamline of the European Synchrotron Radiation Facility (ESRF) using the same setup and parameters as detailed in Table 1 of [21]. Pink X-ray beam of 26 KeV and a PCO.…”

Section: Experimental Methodsmentioning

confidence: 99%

Characterization of the Convoluted 3D Intermetallic Phases in a Recycled Al Alloy by Synchrotron X-ray Tomography and Machine Learning

Qin

Guo

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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“…More recently, increasing attention has been given to the formation of minority intermetallic compound (IMC) phases [15,16,26,104], particularly Fe-rich IMCs, which often form as secondary phases in both cast and wrought alloys and which may grow into coarse (up to several millimetres [106]), plate-like morphologies that undermine alloy ductility and toughness [107,108].…”

Section: Crystal Nucleationmentioning

confidence: 99%

“…Unlike the α-Al solid solution phase, which adopts a non-faceted (frequently dendritic) morphology, IMCs are ordered compounds, generally with relatively high entropy of fusion, that grow with a faceted morphology [109,110]. The past decade has seen an increasing number of in situ X-ray studies of faceted IMC growth, spanning growth kinetics [23][24][25][26]60,111,112], volume fraction evolution [113] and morphology analysis [23,[102][103][104]. Following earlier proof-of-concept investigations of the growth of secondary Fe-rich IMCs by Wang et al using X-ray radiography [111] and Puncreobutr et al using X-ray tomography [60], Cai et al studied secondary β-Al 5 FeSi IMCs in an A319 (Al-Si-Cu) alloy using X-ray tomography [113].…”

Section: Crystal Growthmentioning

confidence: 99%

X-ray Imaging of Alloy Solidification: Crystal Formation, Growth, Instability and Defects

2022

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Synchrotron and laboratory-based X-ray imaging techniques have been increasingly used for in situ investigations of alloy solidification and other metal processes. Several reviews have been published in recent years that have focused on the development of in situ X-ray imaging techniques for metal solidification studies. Instead, this work provides a comprehensive review of knowledge provided by in situ X-ray imaging for improved understanding of solidification theories and emerging metal processing technologies. We first review insights related to crystal nucleation and growth mechanisms gained by in situ X-ray imaging, including solute suppressed nucleation theory of α-Al and intermetallic compound crystals, dendritic growth of α-Al and the twin plane re-entrant growth mechanism of faceted Fe-rich intermetallics. Second, we discuss the contribution of in situ X-ray studies in understanding microstructural instability, including dendrite fragmentation induced by solute-driven, dendrite root re-melting, instability of a planar solid/liquid interface, the cellular-to-dendritic transition and the columnar-to-equiaxed transition. Third, we review investigations of defect formation mechanisms during near-equilibrium solidification, including porosity and hot tear formation, and the associated liquid metal flow. Then, we discuss how X-ray imaging is being applied to the understanding and development of emerging metal processes that operate further from equilibrium, such as additive manufacturing. Finally, the outlook for future research opportunities and challenges is presented.

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“…X-ray imaging has more recently also been applied to study the nucleation/formation and growth of minority, ordered intermetallic compounds (IMCs), which are an important feature of most Al alloys [15,18,[54][55][56][57][58][59][60]. Fe-rich Al IMCs, such as Al 13 Fe 4 , are not always desirable and may grow into coarse (∼10 µm to several millimetres [61]), plate-like secondary phases in both cast and wrought alloys.…”

Section: Nucleation and Growth Of Imcs In Al Alloysmentioning

confidence: 99%

Investigating Metal Solidification with X-ray Imaging

Feng

Han

Lui

et al. 2022

Metals

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In the last two decades, X-ray imaging techniques have been used increasingly to study metal solidification in real-time as, thanks to advances in X-ray sources (synchrotron and laboratory-based) and detector technology, images can now be obtained with spatio-temporal resolutions sufficient to record key phenomena and extract quantitative information, primarily relating to crystal growth. This paper presents an overview of the research conducted at the University of Oxford over the last 6 years as a partner in the UK’s Future Liquid Metal Engineering (LiME) Manufacturing Hub. The focus is on in situ X-ray radiography to investigate the solidification of Al alloys, including the formation of primary α-Al crystals, and the formation and growth of secondary intermetallic phases. Technologically, the thrust is to understand how to control as-cast phases, structures and element distributions, particularly elements associated with recycling, as a means to facilitate greater recirculation of aluminium alloys. We first present studies on refinement of primary α-Al, including extrinsic grain refinement using inoculation and intrinsic refinement based on dendrite fragmentation. Second, we describe studies on intermetallic phase formation and growth, because intermetallic fraction, morphology and distribution are frequently a limiting factor of alloy mechanical properties and recyclability. Then we present some of the latest progress in studying liquid flow during solidification and associated hot tear formation. Finally, future research directions are described.

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Multiscale characterization of the nucleation and 3D structure of Al3Sc phases using electron microscopy and synchrotron X-ray tomography

Abstract: characterization of the nucleation and 3D structure of Al3Sc phases using electron microscopy and synchrotron X-ray tomography, Materials Characterization (2020),

Cited by 20 publications

References 35 publications

Characterization of the Convoluted 3D Intermetallic Phases in a Recycled Al Alloy by Synchrotron X-ray Tomography and Machine Learning

Characterization of the Convoluted 3D Intermetallic Phases in a Recycled Al Alloy by Synchrotron X-ray Tomography and Machine Learning

X-ray Imaging of Alloy Solidification: Crystal Formation, Growth, Instability and Defects

Investigating Metal Solidification with X-ray Imaging

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