Frontiers in Solidification: An MPMD Symposium Honoring Jonathan A. Dantzig: X-ray In Situ Investigations
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS Functional Materials Division, TMS Light Metals Division, TMS Structural Materials Division, TMS: Aluminum Committee, TMS: Chemistry and Physics of Materials Committee, TMS: Process Technology and Modeling Committee, TMS: Solidification Committee
Program Organizers: Andre Phillion, McMaster University; Michel Rappaz, Ecole Polytechnique Fédérale De Lausanne; Melis Serefoglu, Marmara University; Damien Tourret, IMDEA Materials Institute
Tuesday 8:00 AM
March 21, 2023
Room: 28E
Location: SDCC
Session Chair: Sabine Bottin-Rousseau, Sorbonne University; Peter Lee, University College London
8:00 AM Invited
Measuring Key Phenomena in Solidification Using X-ray Imaging: Insung Han1; Shikang Feng1; Enzo Liotti1; Patrick Grant1; 1University of Oxford
X-ray radiography and tomography have been applied widely to investigate the morphological evolution and microstructural instability of pre-existing solid crystals in metal alloys. Solute partitioning between solid and liquid phases has also been resolved for binary alloys, and algorithms are increasingly applied to quantify semi-automatically large image data sets. But little attention has been paid to crystal formation from the liquid behaviour, or to critical phenomena in the residual liquid such as macroscopic flow, macrosegregation, shrinkage and defect formation. This paper presents latest experimental results of the X-ray imaging and quantification of (i) crystal formation behaviour at the beginning of solidification and (ii) flow behaviour and defect formation in the final stages. A range of novel approaches are described that allow dynamic behaviour, including in the liquid, to be quantified. The agreement or otherwise of experiment with theory and modelling is described, along with challenges for future work.
8:30 AM Invited
In Situ X-ray Synchrotron Imaging Investigation of Solidification: Nathalie Mangelinck-Noel1; Guillaume Reinhart1; Gabrielle Regula1; Henri Nguyen-Thi1; 1IM2NP CNRS AMU UMR 7334
All casting processes face challenges linked to grain structure, concentration inhomogeneity and crystalline defects resulting from solidification when aiming at improving the final desired properties. Our contribution consists in the experimental investigation of the growth mechanisms of different materials (from metals to semiconductors) by in situ X-ray imaging during their solidification. A major originality is the simultaneous combination of X-ray radiography and Bragg diffraction (topography) imaging techniques which provide in situ during solidification information on the morphology and kinetics of the solid/liquid interface, solute segregation, misorientations, structural defect dynamics and on the crystal deformation.Results concerning the solidification of metallic alloys (Al-based, superalloys) and silicon for photovoltaic applications will be presented as model cases of dendritic and facetted growth, respectively. These results demonstrate the wide range of growth mechanisms that can be better understood with X-ray imaging applied during solidification and their interest for the comparison with simulation codes.
9:00 AM Invited
Observation of Growing Dendrites by Time-resolved Tomography and Image Processing Using a Phase-field Model: Hideyuki Yasuda1; Arisa Nishiguchi; Ryoji Katsube1; Taka Narumi1; Tomohiro Takaki2; 1Kyoto University; 2Kyoto Institute of Technology
Time-resolved tomography (4D-CT) using synchrotron radiation X-rays has allowed us to observe dendritic growth in metallic alloy systems in situ. However, it is still tricky for Fe- and Ni-based alloys to trace the solid-liquid interface precisely by 4D-CT because of the large X-ray absorption coefficient and the slight difference in the coefficients between the solid and the liquid. In 4D-CT, the reconstructed images were typically obtained every 0.5 - 4 s (cubic voxel of 6.5 μm) and every 4 – 8 s (2 μm) for Al and Fe-based alloys. In image processing using a phase-field model, the solid fractions estimated from 4D-CT were used as a restraint condition, and the phase-field filtering modified the solid-liquid interface in terms of the local curvature. The image processing enabled to evaluate the interface area and the curvatures. The quantitative characterization and some applications of characterization will be discussed.
9:30 AM Break
9:50 AM
In Situ Synchrotron X-ray Diffraction Resolves the Transition from Ferritic to Metastable Austenitic Solidification in Fe-Ni-Cr Alloys: Joseph Aroh1; Seunghee Oh1; S. Thomas Britt1; Emma Barake1; Andrew Chuang2; P. Chris Pistorius1; Anthony Rollett1; 1Carnegie Mellon University; 2Argonne National Laboratory
The transition from ferritic to metastable austenitic solidification in stainless steels has been the subject of many investigations due to its significant impact on the final microstructure. Traditionally, this phenomenon is interpreted through the lens of CALPHAD predictions at the freezing temperature and microstructural characterization at room temperature. However, without substantiating evidence of the phases that appear during solidification and subsequent cooling, it is possible to misinterpret the actual microstructural development history. For this reason, we employed a novel synchrotron x-ray diffraction technique with high spatiotemporal resolution to directly observe and quantify the evolution of phases and temperature during in situ laser melting and re-solidification of Fe-Ni-Cr alloys. The time-resolved diffraction patterns were correlated with post-mortem characterization of the re-solidified melt tracks and competitive growth kinetics modeling. These experiments were performed on a range of Cr/Ni ratios and cooling rates to provide a comprehensive understanding of this elusive phenomenon.
10:10 AM
In Situ X-ray Tomographic Investigations of Dendritic Patterns in a Co-base Alloy during Solidification: Mohammed Azeem1; Tim Wigger2; Andrew Kao3; Nghia Vo4; Robert Atwood4; Peter Lee2; 1University of Leicester; 2University College London; 3University of Greenwich; 4Diamond Light Source Ltd
Co base superalloys and other non-Ni base superalloys are being actively explored for future high efficiency gas turbines in aerospace sector. In both Co and Ni base systems, there is currently lack of morphological information on the formation and evolution of dendritic patterns during solidification. Here we have obtained a time resolved three-dimensional (4D) data of the evolution of α-Co dendritic patterns during solidification using in situ synchrotron X-ray imaging. A parallel decentred octahedral cellular automata solidification code is used to comprehensively quantify, verify and calibrate analytical and numerical coarsening models and dendrite growth simulations, thus enabling predictions for casting applications. Coarse and thick dendritic patterns are observed during slow cooling while fine and thin patterns are observed at fast cooling rates. The development of porosity in the eutectic phase is captured and quantified to assess the defect formation under varying thermal conditions.
10:30 AM
In situ Synchrotron Radiography Investigation of Graphite Nodule Evolution during Solidification in Ductile Cast Iron: Xiangmei Ding1; Tim Wigger2; Niels Tiedje3; Yasuda Hideyuki4; Narumi Taka4; Jenny Shepherd1; Peter Lee2; Mohammed Azeem5; 1University of Leicester; 2University College London, Harwell Campus; 3Technical University of Denmark; 4Kyoto University; 5University of Leicester, Harwell Campus
The size distribution and morphology of graphite nodules are critical for the mechanical properties of ductile cast iron (DCI). High-speed synchrotron radiography is used to understand the nucleation, buoyancy and growth kinetics of graphite nodules during solidification in DCI. Statistical analysis indicates that the size distribution, morphology and velocity of nodules vary significantly during solidification. Initially, the majority of nodules formed tend to move in the melt with little growth. Their movement trajectories in the melt are captured and the growth kinetics are discussed. These fast-moving spherical nodules first form at the bottom of the melt and then their velocity decreases or they become static after the appearance of dendrites. A significant increase in nodule growth rate is then observed. The various morphologies of nodules observed will be discussed, such as the formation of graphite protrusions, flower-ball shapes and the growth of associated austenite shell will be discussed in detail.
10:50 AM
The Impact of Melt Flow on Solidification Patterns in a Ternary Ga-In-Bi Alloy: Natalia Shevchenko1; Olga Budenkova2; Guy Chichignoud2; Sven Eckert1; 1Helmholtz-Zentrum Dresden-Rossendorf; 2Univ. Grenoble Alpes, CNRS
In situ X-ray observations are scarce for ternary and multi-component alloys. A Ga-In-Bi alloy is solidified in a Hele-Shaw cell under buoyancy-driven convection. A complex and strongly disoriented dendrite-type solid phase is formed that differs from a regular dendrite network. It is shown that primary arms of dendrites in a ternary system adapt their velocity to the local concentration ahead of their tips and change continuously or abruptly the growth direction. Some grains exhibit a morphology that is rather similar to the "seaweed" pattern. The appearance of seaweed grains is usually related to a solid/liquid interfacial energy. Further, we focus on the role of melt flow in transition from dendritic arrays to seaweed structures. In particular, it is shown that the splitting of a dendrite tip is preceded by the oscillation of the local intensity of the X-ray pattern which is related to the local concentration of the components.
11:10 AM
Machine Learning Enhanced Operando Study of the Nucleation and Evolution of Complex Intermetallic Phases in Solidification: Kang Xiang1; Jiawei Mi1; 1University of Hull
Microstructural control via the solidification process is the most widely used technology in processing of metallic alloys. Recent advances in synchrotron X-ray based radiography, tomography and scattering techniques have made it possible to observe in real-time the nucleation and evolution of complex metallic phases in the solidification processes. These real-time and in situ research have provided much more insight in understanding the underlying physics in phase transformation at multilength and multi-time scale. For a typical X-ray high-speed radiography and/or tomography experiment with a few tens of TB data collected. It is a challenging task to achieve both efficient and high-fidelity phase segmentation, especially difficult for the convoluted complex multiphases in 3D space. Here, we used a machine learning-based data analysis algorithm to segment the complex and convoluted Fe-based intermetallic phases of an Al-Cu-Fe-Si recycled alloy obtained in operando condition during solidification. Using the machine learning approach, the initial Fe-phase nucleus and the subsequent gradual branching of the phases along different crystallographic directions/planes are revealed clearly. The Chinese-script type Fe phase nucleation and growth dynamics are fully characterized and presented here for the first time.
11:30 AM
In Situ Synchrotron X-ray Radio- and Tomography Analysis of Grain Boundary Formation during Directional Solidification of a Mg Alloy: Maral Sarebanzadeh1; Alberto Orozco-Caballero2; Federico Sket3; Damien Tourret3; Javier LLorca1; 1IMDEA Materials & Universidad Politécnica de Madrid; 2Universidad Politécnica de Madrid; 3IMDEA Materials Institute
The selection of grain boundaries (GBs) during columnar solidification of hcp alloys is less explored than in cubic (fcc, bcc) systems. In this study, GBs forming during directional solidification of polycrystalline magnesium (Mg) alloys are investigated via in situ synchrotron X-ray imaging. Two experimental setups were designed that each consist of two heating elements generating a controlled thermal gradient and cooling rate in the sample. Alloy samples are encapsulated in an Ar atmosphere to avoid oxidation. Resulting time-resolved radiographs or tomographs during melting and solidification of various binary Mg alloys (e.g. Mg-Gd) provide quantitative data on the dendritic growth dynamics and the selection of GBs during polycrystalline dendritic growth in hcp alloys. Beyond validating the apparatus and highlighting its potential for in situ characterization of dynamical phenomena in metallic alloys solidification, these results are discussed in light of phase-field simulations of bi-crystal grain growth competition.