Article
Physics, Fluids & Plasmas
E. S. Nani, Britta Nestler
Summary: The asymptotic analysis of multi-phase-field models is often not rigorously performed, and the justification for certain model assumptions is usually heuristic. The transition from an initial filling to a state characterized by separated bulk phases is rarely addressed, and there is a lack of detailed numerical studies on the predicted asymptotic laws.
Article
Materials Science, Multidisciplinary
Yanqiang Li, Hongxiang Jiang, Hao Sun, Lili Zhang, Jie He, Jiuzhou Zhao
Summary: This study demonstrates that composite electric and magnetic fields (CEMFs) can decrease the size of minority phase particles and promote a more uniform distribution. A theoretical model is established to describe the microstructure evolution during cooling. Numerical simulations are consistent with experimental data, showing that CEMFs affect solidification process by changing melt convection and nucleation behavior.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Yanbin Zhang, Bin Zhu, Haijun Jiang, Li Tan, Yu Weng, Yi Yang, Ling Qin
Summary: The roles of traveling magnetic fields (TMFs) during the solidification of nickel-based superalloys were simulated, and the evolution of thermal field, flow field, and solid-liquid interface morphology under different convection conditions were compared. The strength of TMFs in suppressing the interfacial flow was quantified, and its association with defect formation was discussed.
Article
Materials Science, Multidisciplinary
Keli Liu, Junsheng Wang, Yanhong Yang, Yizhou Zhou, Yuansheng Yang, Chunjie Cao
Summary: Shrinkage microporosity formed during the directional solidification of Ni-based single crystal superalloys can significantly reduce turbine blade fatigue life, potentially leading to catastrophic flight accidents. An integrated mesoscale model combining cellular automaton method and X-ray microtomography characterization successfully predicted the relationship between pore size, percentage, distribution, and directional solidification conditions, revealing the root cause of pore size distributions.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Jingying Xu, Jinwu Kang, Lele Zheng, Weimin Mao, Jiwu Wang
Summary: The application of a multi-shell mold structure in directional solidification is studied, and the insulation effect and solidification front morphology of this structure are simulated and verified through experiments.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
Jee Seok Choi, Moonwoo La, DongEung Kim, Kyeong-Hwan Choe, Soong-Keun Hyun, Moon-Jo Kim
Summary: The effect of electric current on the refinement of pure aluminum during solidification was investigated in this study. It was found that electric current can significantly alter the grain morphology and reduce grain size. The grain refinement is influenced by electrical conditions such as the intensity and duration of applied electric current, but under extreme conditions, the refining effect may disappear.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Materials Science, Multidisciplinary
Xianqiang Fan, Natalia Shevchenko, Catherine Tonry, Samuel J. Clark, Robert C. Atwood, Sven Eckert, Koulis Pericleous, Peter D. Lee, Andrew Kao
Summary: Solute channel formation can occur in various processes and is influenced by the interaction between an external magnetic field and thermoelectric currents at solid/liquid interfaces. In this study, we used in situ synchrotron X-ray imaging and numerical simulations to investigate the characteristics of flow and solute transport under thermoelectric magnetohydrodynamic (TEMHD) effects. Our observations suggest that macroscopic and microscopic TEMHD flows are the primary mechanisms controlling plume migration and channel bias. We also discovered that grain orientation can modify solute flow through anisotropic permeability. These findings led to the proposed strategy of using a time-modulated magnetic field for solute channel-free solidification.
Article
Materials Science, Multidisciplinary
Shaodong Hu, Long Hou, Kang Wang, Zhongmiao Liao, Wen Zhu, Aihua Yi, Wenfang Li, Yves Fautrelle, Xi Li
Summary: Research indicates that thermoelectric magnetic convection (TEMC) under transverse static magnetic field leads to solute enrichment on one side of the sample, affecting primary dendrite arm spacing and freckle formation. The impact intensifies with an increase in magnetic field strength.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Jinge Yan, Tie Liu, Mengmeng Wang, Jinmei Sun, Shulin Dong, Lijia Zhao, Qiang Wang
Summary: Directional solidification experiments of eutectic Al-Fe alloys were conducted under different high magnetic field gradients. The study found that high magnetic field gradient changed the microstructure selection during solidification process, leading to different solidification structures. A solidification model of eutectic alloy under high magnetic field gradient was proposed, and the microstructure selection map of Al-Fe alloy under gradient magnetic field was qualitatively drawn for the first time. These findings have significant implications for controlling the structure and properties of alloys.
MATERIALS CHARACTERIZATION
(2022)
Article
Engineering, Multidisciplinary
M. Maduka, C. W. Li
Summary: This study investigates various flanged duct turbines with different duct geometries under bi-directional flow conditions using CFD analysis. The results show that a flanged duct turbine with an inlet-arc flap and curved brim can achieve a maximum value of C-P* close to the Betz-Joukowsky limit for flow from either direction. Furthermore, it was observed that the effect of flow confinement on C-P* indicates an increase in C-P* with blockage ratio epsilon.
ENGINEERING APPLICATIONS OF COMPUTATIONAL FLUID MECHANICS
(2021)
Article
Crystallography
Satoshi Nakano, Xin Liu, Xue-Feng Han, Koichi Kakimoto
Summary: This study investigated the effect of evaporation flux on phosphorus concentration distribution in silicon crystal by numerical analysis, finding that controlling phosphorus evaporation flux can achieve a homogeneous phosphorus concentration distribution.
Article
Mechanics
Holger Grosshans, Claus Bissinger, Mathieu Calero, Miltiadis Papalexandris
Summary: Through direct numerical simulations, we found that under certain density ratios and Coulombic-to-gravitational force ratios, electrostatic forces play a dominant role in the vortical motion of particles, affecting their distribution within the duct.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Francisco Ricardo Cunha, Adriano Possebon Rosa
Summary: This study investigates the viscoelastic behavior of a ferrofluid undergoing oscillatory simple shear flow and an external magnetic field, exploring the influence of dipolar interactions and anisotropic structures. The results suggest that dipolar interactions lead to a viscoelastic transition in the fluid, possibly due to the formation of complex structures like anisotropic chains. Additionally, the relaxation time of the ferrofluid shows a quadratic power law scaling dependence on the dipolar interaction parameter, indicating that dipolar interactions play a key role in creating the elastic response of the ferrofluid.
Article
Physics, Fluids & Plasmas
Ruben E. Rojas, Artur Perevalov, Till Zurner, Daniel P. Lathrop
Summary: The study investigates torque and velocity measurements in a 40-cm spherical Couette flow experiment with rough boundaries, comparing with previous work on smooth boundaries. Different baffle designs were tested to observe significant differences in torque as a function of Reynolds and Rossby numbers, as well as an enhancement in equatorial jet and poloidal flows. It was found that one of the chevronlike baffle designs shows promise as an upgrade to increase the chances of obtaining dynamo action in the experiment.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Materials Science, Multidisciplinary
Qingdong Zhong, Huaiyu Zhong, Hongbo Han, Mingyong Shu, Long Hou, Yanyan Zhu, Xi Li
Summary: The influence of axial static magnetic field on macro-segregation and structure in Al-Cu and NiMn-Ga alloys during directional solidification was investigated. It was found that ring-like structures formed under moderate magnetic fields at specific growth speeds. Numerical simulations revealed the formation of rotary thermoelectric magnetic convection in the mushy zone under an axial magnetic field, inducing the ring-like macro-segregation and structure. The experimental results agreed well with the numerical results, attributing the formation of ring-like structure and segregation to solute redistribution induced by thermoelectric magnetic convection.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Mechanical
R. Nauber, N. Thieme, H. Radner, H. Beyer, L. Buettner, K. Dadzis, O. Paetzold, J. Czarske
FLOW MEASUREMENT AND INSTRUMENTATION
(2016)
Article
Acoustics
Norman Thieme, Paul Boenisch, Dagmar Meier, Richard Nauber, Lars Buettner, Kaspars Dadzis, Olf Paetzold, Lamine Sylla, Juergen Czarske
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2017)
Article
Crystallography
K. Dadzis, P. Boenisch, L. Sylla, T. Richter
JOURNAL OF CRYSTAL GROWTH
(2017)
Article
Crystallography
D. Meier, G. Lukin, N. Thieme, P. Boenisch, K. Dadzis, L. Buettner, O. Paetzold, J. Czarske, M. Stelter
JOURNAL OF CRYSTAL GROWTH
(2017)
Article
Crystallography
M. Nicolai L. Lorenz-Meyer, Robert Menzel, Kaspars Dadzis, Angelina Nikiforova, Helge Riemann
CRYSTAL RESEARCH AND TECHNOLOGY
(2020)
Article
Engineering, Electrical & Electronic
K. Dadzis, R. Menzel, U. Juda, K. Irmscher, C. Kranert, M. Mueller, M. Ehrl, R. Weingaertner, C. Reimann, N. Abrosimov, H. Riemann
JOURNAL OF ELECTRONIC MATERIALS
(2020)
Article
Crystallography
H-J Rost, I Buchovska, K. Dadzis, U. Juda, M. Renner, R. Menzel
JOURNAL OF CRYSTAL GROWTH
(2020)
Article
Crystallography
Andrejs Sabanskis, Kaspars Dadzis, Robert Menzel, Janis Virbulis
Summary: Numerical simulations were conducted on the transient temperature field and dislocation density distribution during a silicon crystal heating experiment. Both low- and high-frequency modeling approaches yielded similar results, which were in good agreement with the experiment. An extension of the Alexander-Haasen model successfully explained the observed dislocation distribution, with some remaining shortcomings in the model discussed.
Article
Chemistry, Multidisciplinary
Christo Guguschev, Carsten Richter, Mario Bruetzam, Kaspars Dadzis, Christian Hirschle, Thorsten M. Gesing, Michael Schulze, Albert Kwasniewski, Juergen Schreuer, Darrell G. Schlom
Summary: In this study, we demonstrate the growth of large (Mg,Zr):SrGa12O19 single crystals and use X-ray imaging techniques to analyze their structural and chemical homogeneity. We developed a lab-based X-ray diffraction imaging technique that can detect subtle variations in lattice parameters and lattice tilts attributed to changes in chemical composition and resulting elastic deformation. Micro X-ray fluorescence mapping was used to verify the relationship between unit-cell dimensions and composition. The SGMZ crystals exhibited good structural quality and homogeneity, making them suitable for high-quality substrate preparation.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Crystallography
O. Paetzold, K. Dadzis, C. Kirmse, D. Weik, L. Buettner, J. Czarske, A. Charitos
Summary: The melt flow is crucial for Cz growth of silicon crystals, and in-situ measurement data are important for process development. This study presents new low-temperature model experiments and numerical simulations to investigate Cz type melt flow. A novel experimental setup with advanced measurement techniques is used to obtain accurate data for validation. The study reveals the occurrence of flow transitions between symmetric and non-symmetric structures under certain conditions.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Crystallography
A. Enders-Seidlitz, J. Pal, K. Dadzis
Summary: The Czochralski process is an important technique for producing bulk single crystals. A new 2D open-source thermal CZ growth model is introduced in this study, which is verified and validated using analytical solutions and dedicated model experiments. The model considers gas and melt convection and successfully predicts the influence of crystal pull velocity and melt temperature on crystal diameter.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Engineering, Mechanical
Florian Buerkle, Maik Foerste, Kaspars Dadzis, Iason Tsiapkinis, Olf Paetzold, Alexandros Charitos, Michael Dues, Juergen Czarske, Lars Buettner
Summary: Crystal growth process is a crucial step in the fabrication of modern semiconductor materials and devices. Researchers used optical measurement methods to study the gas flow behavior inside a crystal growth furnace, providing reference data for improving the crystal growth process.
FLOW MEASUREMENT AND INSTRUMENTATION
(2022)
Article
Energy & Fuels
Iryna Buchovska, Kaspars Dadzis, Natasha Dropka, Frank M. Kiessling
Summary: This study presents a novel approach to reduce the inhomogeneity of resistivity in n-type phosphorus-doped silicon ingots by manipulating the dopant transport during the growth process. Different process conditions, such as altering ambient gas pressure, enhanced melt mixing, and variations of argon flow, were tested to achieve a more uniform resistivity profile. The quality of the ingots was characterized in terms of electrical resistivity, minority carrier lifetime, and the presence of impurities and inclusions. The results show that the complex approach to melt stirring and gas transport effectively controls the resistivity distribution in phosphorus-doped multicrystalline ingots, making it comparable to boron-doped p-type ones.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Crystallography
Kirils Surovovs, Maksims Surovovs, Andrejs Sabanskis, Janis Virbulis, Kaspars Dadzis, Robert Menzel, Nikolay Abrosimov
Summary: The distribution of dopants and impurities in silicon grown with the floating zone method is essential for determining the electrical resistivity and other important properties of the crystals. Segregation at the crystallization interface plays a crucial role in defining the transport of these species. A new coupled numerical model was developed to investigate the influence of melt flow on the effective segregation coefficient, global species transport, and resulting distribution in the grown crystal. The simulation results show that the effective segregation coefficient increases with larger melt diameters due to less intensive melt mixing during the growth process.
Article
Crystallography
Jianzheng Hu, Long Yan, Ning Zhou, Yao Chen, Xiaoni Yang, Lianqiao Yang, Shiping Guo
Summary: The effect and mechanism of carrier gas velocity, V/III ratio, and carrier gas velocity match on the growth rate of AlN were investigated in this study. The results showed that the growth rate of AlN initially increased with hydrogen flow rate, reached saturation, and then decreased monotonically. The turning point value depended on the equipment and process. By increasing the MO VM, the growth rate of AlN could be improved, but the uniformity deteriorated due to turbulence and loss of uniform boundary layer. High quality AlN films were successfully grown on nano-patterned sapphire substrates with improved crystalline quality and atomic smooth surfaces.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Tingting Ma, Yang Li, Kangning Sun, Qinglin Cheng, Sen Li
Summary: This study investigates the melting process and nucleation behavior of sodium crystals using molecular dynamics simulation. The results show good agreement between simulated and experimental values for the melting temperature, density, and radial distribution function of sodium. The diffusion coefficient of liquid sodium increases linearly with temperature, and the homogeneous nucleation rate of melting in superheated sodium crystal exponentially increases with temperature. The findings provide theoretical support for applications involving heat and mass transfer in sodium-related systems.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Hisato Nishii, Shintarou Iida, Akira Yamasaki, Takumi Ikenoue, Masao Miyake, Toshiya Doi, Tetsuji Hirato
Summary: Epitaxial V2O3 films were fabricated on sapphire substrates using mist chemical vapor deposition (mist CVD) method, eliminating the need for high vacuum conditions. The films can be grown on sapphire substrates even under atmospheric pressure, with the optimal growth temperature at 823 K. The films grown at 823 K exhibit a metal-insulator transition at approximately 155 K. The film on C-plane sapphire exhibits a lower transition temperature compared to those on R- and A-plane sapphire substrates.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Jani Jesenovec, Kevin Zawilski, Peter Alison, Stephan J. Meschter, Sambit K. Saha, Andrew J. Sepelak, Peter G. Schunemann
Summary: In this study, NiSb needles were successfully formed in InSb by manipulating the growth rate and adding NiSb. These needle structures in InSb can be used to tune the magnetoresistance of devices. Additionally, undoped InSb crystals demonstrated good infrared transmission at low growth rates.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
D. Joseph Daniel, P. Karuppasamy, H. J. Kim
Summary: The 2-amino 4-methyl pyridinium oxalate (2A4MPO) compound was synthesized and its crystal structure, functional groups, thermal stability, electrical properties, and third-order nonlinear optical properties were studied. The results demonstrate that the synthesized crystal has good structural integrity, thermal stability, and potential for third-order nonlinear optical applications.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
C. W. Lan
Summary: The past two decades have witnessed a significant transformation in solar silicon crystal growth, especially in the competition between multi-crystalline silicon (Multi-Si) and mono-crystalline silicon (Mono-Si). The demand for this crucial material has exponentially surged, with silicon solar panels capturing over 95% of the global PV market share. The advancements in crystal growth technology during this period have set historical benchmarks, with the market share shifting from high-performance multi-crystalline silicon (HPM-Si) to CZ silicon.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Peiyao Hao, Lili Zheng, Hui Zhang
Summary: A novel design of argon gas tube for removing impurities during silicon ingot growth was developed, and numerical simulations showed that it can effectively extract SiO.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Geetika Sahu, Chanchal Chakraborty, Subhadeep Roy, Souri Banerjee
Summary: This article discusses the novel fractal nature of hydrothermally synthesized MoS2 QDs. By adjusting the reaction time, the study found that the average size of QDs increases and then decreases with longer reaction times. STEM images indicate that shorter reaction times lead to sheet formation, while extended reaction times cause sheets to fragment into QDs.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Pengjian Lu, Wei Huang, Junjun Wang, Haitao Yang, Shiyue Guo, Bin Li, Ting Wang, Chitengfei Zhang, Rong Tu, Song Zhang
Summary: A systematic study on the tetramethylsilane-hydorgen (TMS-H-2) system for the deposition of pure single-crystal SiC by high-temperature chemical vapor deposition (HTCVD) method is conducted. The study investigates the effect of temperature, pressure, and H-2:TMS ratio on the deposition conditions and provides a theoretical basis and guidance for improving the quality and cost of industrial production of single-crystal SiC.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Xinyu Jiang, Liangliang Liu, Yanqing Liu, Yan Wang, Zhaoping Hou
Summary: Investigation on the preparation of anisometric templated textured high entropy or multi-element doped ferroelectric ceramics was conducted using A-site disordered niobate microcrystals. The effects of process parameters on the morphology and chemical composition were studied, and the photocatalytic properties of the microcrystals were evaluated.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Mobashsara Tabassum, Md. Ashraful Alam, Sabrina Mostofa, Raton Kumar Bishwas, Debasish Sarkar, Shirin Akter Jahan
Summary: In this study, high crystallinity copper nanoparticles were synthesized by altering the reaction medium at low temperatures. The results show that changing the reaction medium can reduce the surface energy of precursors and promote the formation of highly crystalline copper nanoparticles.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Ivan Bodnar, Vitaly V. Khoroshko, Veronika A. Yashchuk, Valery F. Gremenok, Mohsin Kazi, Mayeen U. Khandaker, Tatiana I. Zubar, Daria I. Tishkevich, Alex Trukhanov, Sergei Trukhanov
Summary: This work presents the production of single crystals of Cu2ZnGeSe4, a semiconducting quaternary compound, using a gas chemical method with iodine as a transporter. The phase state, crystal structure, and lattice constants of the synthesized samples were refined and determined. The band gap of Cu2ZnGeSe4 was calculated using transmission spectrum and it was found that the band gap increases by 12% with decreasing temperature in the range of 20-300 K.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Timur Malin, Igor Osinnykh, Vladimir Mansurov, Dmitriy Protasov, Sergey Ponomarev, Denis Milakhin, Konstantin Zhuravlev
Summary: The effect of growth temperature on the buffer leakage currents of GaN-on-Si layers was investigated. It was found that higher growth temperature results in lower leakage currents. The defects in GaN layers grown at different temperatures were studied using photoluminescence technique, and a correlation between leakage currents, structural perfection, and donor concentration in GaN-on-Si layers was established. It was also observed that reduced growth temperature leads to the formation of inversion domains.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Thi-Hoai-Thu Nguyen, Jyh-Chen Chen
Summary: The effect of heater power control on heat, flow, and oxygen transport for CCz crystal growth was studied. Shorter upper side heater design could improve crystal quality and growth, but with higher power consumption.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Peter Rudolph
Summary: This article presents an overview of selected contributions to the development of crystal growth technology by the Laudise Prize awardee 2023. It discusses various aspects such as shaped crystal growth, the correlation between melt structure and crystal quality, control of intrinsic defects and inclusions, prevention of dislocation cell patterns, and melt growth experiments under a travelling magnetic field.
JOURNAL OF CRYSTAL GROWTH
(2024)