Impact of solute flow during directional solidification of a Ni-based alloy: In-situ and real-time X-radiography

Reinhart, Gunther; Grange, David; Abou-Khalil, L.; Mangelinck‐Noël, Nathalie; Niane, N.T.; Maguin, V.; Guillemot, Gildas; Gandin, Charles‐André; Nguyen-Thi, Henri

doi:10.1016/j.actamat.2020.04.003

Cited by 52 publications

(48 citation statements)

References 53 publications

(70 reference statements)

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“…The close link between dendrite tip velocity and solute plume motion ahead of the dendrite tip ( Fig. 8) has been already mentioned by Shevchenko et al [32] for the study of Ga-In, and more recently by Reinhart et al [60] during directional solidification of superalloys. The explanation for these cycles running concurrently is that solute plumes locally increased the Cu concentration ahead of the dendrite tip, which reduced the constitutional undercooling intensity and thus slowed the dendrite tip growth [61].…”

Section: Discussionsupporting

confidence: 70%

Impact of gravity on directional solidification of refined Al-20wt.%Cu alloy investigated by in situ X-radiography

Soltani

Ngomesse

Reinhart

et al. 2021

Journal of Alloys and Compounds

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Gravity effects such as natural convection in the liquid phase and buoyancy forces acting on the solid phase have a strong influence on the grain structure and microstructure formation dynamics during the solidification of metal alloys. It is thus very useful to undertake experimental studies that will provide benchmark data for a deeper understanding of the role of such gravity effects. In this paper, we study the formation of the equiaxed grain structure during refined Al-20wt.%Cu solidification in a temperature gradient for three different configurations: horizontal, vertical upward and vertical downward solidification. The key grain characteristics, namely grain size, grain elongation and grain growth orientation, were determined for all experiments and a comparative study was performed to identify the dominant effects of gravity 2 for each case. The present study provides quantitative information on the impact of grain flotation and solute flows on the equiaxed microstructure characteristics by means of in situ laboratory X-radiography.

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Section: Discussionsupporting

confidence: 70%

Impact of gravity on directional solidification of refined Al-20wt.%Cu alloy investigated by in situ X-radiography

Soltani

Ngomesse

Reinhart

et al. 2021

Journal of Alloys and Compounds

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“…However, the contrast between the solid and liquid phase is then only about 4%. Due to the limited density difference and the compromise in energy, the solid-liquid interface is hardly distinguishable on the raw images oppositely to the case of alloys for which a higher density difference is obtained because of the presence of several phases and of solute [56]. In addition, the legibility of the images is considerably affected by the unavoidable non-uniform profile of the X-ray beam and by the surface inhomogeneity of the silicon crystals in the post-monochromator.…”

Section: X-ray Radiographymentioning

confidence: 93%

X-ray Based in Situ Investigation of Silicon Growth Mechanism Dynamics—Application to Grain and Defect Formation

et al. 2020

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To control the final grain structure and the density of structural crystalline defects in silicon (Si) ingots is still a main issue for Si used in photovoltaic solar cells. It concerns both innovative and conventional fabrication processes. Due to the dynamic essence of the phenomena and to the coupling of mechanisms at different scales, the post-mortem study of the solidified ingots gives limited results. In the past years, we developed an original system named GaTSBI for Growth at high Temperature observed by Synchrotron Beam Imaging, to investigate in situ the mechanisms involved during solidification. X-ray radiography and X-ray Bragg diffraction imaging (topography) are combined and implemented together with the running of a high temperature (up to 2073 K) solidification furnace. The experiments are conducted at the European Synchrotron Radiation Facility (ESRF). Both imaging techniques provide in situ and real time information during growth on the morphology and kinetics of the solid/liquid (S/L) interface, as well as on the deformation of the crystal structure and on the dynamics of structural defects including dislocations. Essential features of twinning, grain nucleation, competition, strain building, and dislocations during Si solidification are characterized and allow a deeper understanding of the fundamental mechanisms of its growth.

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“…Laser-based sources provide direct, localised heating on the surface of the crucible holding the sample, and enable fast heating (up to 100 °C/min) and cooling rates (e.g., [ 25 , 58 ]). A number of studies have predominantly used resistive [ 59 ] and infrared [ 37 ] heating chambers enclosed around the specimen (as shown in the schematic of Figure 2 ). Resistive furnaces are relatively inexpensive, but heating rates are limited to a few degrees (°C) per second, while infrared furnaces can achieve faster heating rates (on small samples) but are less stable and expensive.…”

Section: A Brief Review Of Techniquesmentioning

confidence: 99%

“…The combination of high resolution and fast acquisition, coupled with improved analysis methods have also evolved to identify geometrical characteristics of evolving features in metals, such as curvatures of dendritic tips, and other phases [ 102 , 108 ]. Recently, Reinhart et al, [ 59 ] demonstrated the imaging of Ni-based alloys during solidification, clearly identifying columnar directionally solidified microstructures and solute channel formation ( Figure 7 c). The authors used a CMSX-4 superalloy specimen in a gradient furnace to capture real-time observations at about 0.1 s time intervals.…”

Section: X-ray Imaging Of Solidification Processesmentioning

confidence: 99%

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Progress on In Situ and Operando X-ray Imaging of Solidification Processes

2021

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In this review, we present an overview of significant developments in the field of in situ and operando (ISO) X-ray imaging of solidification processes. The objective of this review is to emphasize the key challenges in developing and performing in situ X-ray imaging of solidification processes, as well as to highlight important contributions that have significantly advanced the understanding of various mechanisms pertaining to microstructural evolution, defects, and semi-solid deformation of metallic alloy systems. Likewise, some of the process modifications such as electromagnetic and ultra-sound melt treatments have also been described. Finally, a discussion on the recent breakthroughs in the emerging technology of additive manufacturing, and the challenges thereof, are presented.

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Impact of solute flow during directional solidification of a Ni-based alloy: In-situ and real-time X-radiography

Cited by 52 publications

References 53 publications

Impact of gravity on directional solidification of refined Al-20wt.%Cu alloy investigated by in situ X-radiography

Impact of gravity on directional solidification of refined Al-20wt.%Cu alloy investigated by in situ X-radiography

X-ray Based in Situ Investigation of Silicon Growth Mechanism Dynamics—Application to Grain and Defect Formation

Progress on In Situ and Operando X-ray Imaging of Solidification Processes

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