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Revealing growth mechanisms of faceted Al2Cu intermetallic compounds via high-speed synchrotron X-ray tomography

DOI: 10.1016/j.actamat.2022.117903 DOI Help

Authors: Zihan Song (University of Birmingham) , Oxana V. Magdysyuk (Diamond Light Source) , Tay Sparks (University of Birmingham) , Yu-Lung Chiu (University of Birmingham) , Biao Cai (University of Manchester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acta Materialia , VOL 5

State: Published (Approved)
Published: March 2022
Diamond Proposal Number(s): 19216

Open Access Open Access

Abstract: This study usedhigh-speed synchrotron X-ray tomography to image the growth of Al2Cu intermetallic compoundsin 4D (3D plus time) during solidification of Al-45wt%Cu alloy. Two categories of growth patterns (basic units and dendrites) are identified. Basic unitsare elongated rods whose cross-section areL, U orhollow-rectangularshapes. The transition from L pattern to U and finally to hollow-rectangularshaped morphologywas observed. Faceted dendritic patterns include equiaxed prism and columnar dendrites. Self-repeated layer-by-layer stacking of the basic units (such as L shaped particles) is proposed as a governing mechanism for the growth of Al2Cu faceted dendrites. The growth orientation and morphologies of these patterns are strongly influenced by solidification conditions (temperature gradients, cooling rates and external magnetic fields). Another finding is that when rotating Al-45wt%Cu during upwards directional solidification,under a transverse magnetic field of 0.5T, highly refined and well aligned Al2Cu intermetallic compounds are obtained, much finer than those without the imposition of the magnetic field. This is attributed to a rotational stirring flow that modulates and regulates the temperature and solute distribution.The developed experimental findings provide a physical understanding of the formation of faceted intermetallic compounds during solidification.

Journal Keywords: intermetallic; crystal growth; synchrotron x-ray tomography; magnetic field-assisted solidification

Diamond Keywords: Alloys

Subject Areas: Materials, Engineering

Instruments: I12-JEEP: Joint Engineering, Environmental and Processing

Added On: 04/04/2022 09:49


Discipline Tags:

Materials Engineering & Processes Materials Science Engineering & Technology Metallurgy

Technical Tags:

Imaging Tomography