Distribution Of Inclusions Research Articles

Evolution of Inclusion Distribution in Continuous Casting Slabs During Strip Feeding

Evolution of Inclusion Distribution in Continuous Casting Slabs During Strip Feeding

Effects of oxygen content, Mn/S ratio, Cu content, hot-rolling, and annealing on morphology/distribution of MnS inclusions and microstructure/mechanical properties of free-cutting stainless steel

Free-cutting steel, renowned for its exceptional machinability, is susceptible to the impact of manganese sulfide (MnS) and other non-metallic inclusions on the cutting performance and mechanical properties. The composition, morphology, and distribution of these inclusions are influenced by the total oxygen content and doping elements in free-cutting steel. This study focused on three S303 free-cutting steels with different S, Mn, and Cu contents, and the as-received samples were subjected to deoxidation and oxidation remelting, respectively, using a high-vacuum arc melting furnace to control the oxygen content. Thermo-Calc simulations were employed to predict the phases and phase proportions under different processing conditions and to compare with measurements. While the oxygen content was found to subtly affect the distribution and morphology of MnS inclusions, the Mn/S ratio notably affected the size and quantity of MnS inclusions, consequently impacting the mechanical properties of the steel. Higher Cu contents resulted in Cu segregates in the matrix but did not exist in MnS or form CuO; however, it significantly reduced strain hardening. Comparisons between hot-rolled and annealed samples revealed that the most significant changes in mechanical properties resulted from the release of residual stresses. In nanoindentation tests, it was observed that the hardness of MnS inclusion was influenced mainly by residual stresses not doping elements.

Effects of Ce addition on inclusion modification in martensitic stainless steel

The control of inclusion features, i.e., chemical composition, distribution, quantity, and size, is in high demand for stainless steels to achieve good surface quality, pitting corrosion resistance, and mechanical properties. In this paper, the effects of rare earth (RE) modification on the inclusions of martensitic stainless steel were explored. Martensitic stainless steels with various contents of Ce were prepared, and the inclusions in the cast billets were characterized by field emission scanning electron microscopy (FE-SEM) and an automatic analysis system for nonmetallic inclusions in steels (OTS). The effect of Ce on the modification of nonmetallic inclusions during solidification was explored with thermodynamic calculations. The results showed that the addition of Ce modified the oxygen and sulfur inclusions by transforming them from irregular elongated inclusions to nearly spherical RE composite inclusions. Compared with those in basic martensitic stainless steel, nine types of RE inclusions were found in the presence of Ce. As the Ce content increased from 0.048 wt% to 0.092 wt%, the CeAlO3 content decreased, whereas the Ce2O2S content increased. Moreover, there were 80% fewer inclusions than in the basic martensitic stainless steel.

The study on interaction mechanisms between Ti48Al2Cr2Nb alloy and Y2O3 ceramic crucibles with good thermal shock resistance: Assessing a novel, cost-effective approach to the preparation of high-performance TiAl alloys

Enhancing the thermal shock resistance of Y2O3 ceramic crucibles, coupled with advancements in melting and casting technologies to reduce the adverse influence of interfacial reactions, is essential for producing low-energy consumption, high-quality titanium-aluminum (TiAl) alloys. In this study, the Y2O3 ceramic crucible with good thermal shock resistance was developed through the optimization of particle size distribution and sintering holding time. The interaction mechanisms between Y2O3 ceramics and TiAl alloys under extreme conditions were investigated, and strategies for enhancing the mechanical properties of TiAl alloys through the integration of Y2O3 crucibles with centrifugal casting were discussed. The results indicated that introducing large particles of 1–3 mm under sintering conditions of 2023 K and 6 h effectively enhances the thermal shock resistance of Y2O3 crucible. The interaction between Y2O3 and TiAl alloys primarily involved physical erosion (spalling/dispersion), dissolution of separated particles, and surface modification of interface layer particles (reaction). Physical erosion played an important role in this dynamic interaction, with the extent of erosion intensifying through continuous use of the crucible, while electromagnetic forces ensured the uniform distribution of inclusions within the TiAl alloy matrix. Moreover, the application of centrifugal casting technology substantially refines the grain size and reduces the inclusion count, thereby significantly enhancing the mechanical properties of TiAl alloy.

Numerical modeling of shrinkage induced cracking in cementitious materials with three-dimensional simulation and phase-field method

This study investigates the damage and cracking of concrete induced by drying shrinkage. While previous studies have primarily focused on two-dimensional configurations, this research employs three-dimensional phase-field simulations of concrete samples undergoing the drying process. The distribution of inclusions is derived from tomographic images of real samples. The analysis includes the evolution of the damage field and the propagation of cracked zones. The study introduces the formulation and implementation of the numerical method and applies it to elucidate the cracking process resulting from drying shrinkage in concrete composites with various types of inclusions. Numerous numerical simulations were conducted to accurately depict the cracking process induced by drying shrinkage in the samples, evaluating the effects of different inclusions with varying stiffness on the concrete’s cracking phenomenon and comparing the impact of various energy degradation methods on crack simulation. Moreover, the study analyzes the influence of the spatial distribution of the inclusions in the three-dimensional simulation and compares the numerical results with experimental observations.

FE modeling to generate composite RVEs with high volume fractions and various shapes of inclusions

This work proposes a novel multi-step dynamic FE compression method to generate Representative Volume Elements (RVEs) of composites containing a variety of inclusions. This method is actualized through a sequential and four-stage procedure: (1) Sparse and periodic inclusions exhibiting a predefined orientation distribution are generated by implementing a modified random sequential adsorption algorithm, (2) Sparse inclusions undergo biaxial compression into the region of the targeted RVE via a dynamic FE analysis, (3) Periodic inclusions are compressed into the region utilizing a dynamic FE analysis with periodic boundary conditions, and (4) Positions and orientations of the compressed inclusions are extracted and the RVE in computer-aided design format is then generated. The proposed method confers advantages from four distinct perspectives: (1) applicability to various inclusion geometries, including ellipses, lobules, polygons, kidneys and stars, (2) ability to generate periodic RVEs of composites with high inclusion volume fractions (up to 80.0% for circular inclusions), (3) simple and straightforward numerical implementation without explicitly considering inclusion intersection check and (4) capacity to predefine inclusion orientation distribution. Statistical analyses utilizing multiple spatial descriptors, i.e., inclusion orientation angle, local volume fraction, Voronoi cell area, nearest-neighbor distance and orientation, second order intensity function, radial distribution function and two-point probability function, confirm randomness of inclusion distribution in the generated RVEs. The elastic properties and damage behaviors of composites via the FE homogenization method are predicted based on the generated RVEs and are compared with those of available experimental data, the literature and the mean-field homogenization models to demonstrate effectiveness of the proposed multi-step dynamic FE compression method.

Modified Bridgman assisted ZnTe crystal growth for THz device applications

Zinc Telluride (ZnTe) single crystals have enormous potential for generating and detecting broadband terahertz (THz) radiation, making them suitable for a wide range of applications in communication, defence security and biomedical applications. The quality and homogeneities of the crystal plays an important role in obtaining THz response. This paper elaborates on the steps involved in the crystal growth of ZnTe and the characterization technique utilized for the determination of quality of the grown crystal, identifications of defects and qualifications of THz signals. Single crystal was grown by the Bridgman technique in vacuum sealed carbon-coated quartz ampoule with excess tellurium (Zn:Te/3:7). To obtain maximum THz response, crystals were oriented along (110) direction using a Laue diffraction pattern and sliced accordingly. Three different crystals along the length (bottom-middle-top) of size ∼ 10 mm × 10 mm are taken for analysis. The crystallinity of ZnTe was confirmed with X-ray diffraction pattern and lattice parameters were obtained using Rietveld refinement. Raman analysis was carried out at three different regions of the grown crystal which revealed the presence of same high-intensity mode at 413 cm−1 in all the regions confirming the quality of the crystal. The EDS compositional analysis confirms the stoichiometry along the grown crystal length. Optical bandgap of 2.216 eV was measured by UV-Vis-NIR spectra and >55 % transmission was obtained across the grown crystal length. The size and distribution of Te inclusions were measured using IR microscopy. The crystals were subjected to terahertz investigation in the range of 0.1–4 THz using a time domain spectrometer. All the crystals exhibited negligible absorption coefficients in the 0.1–3.75 THz range, confirming the maximum transmission in the THz domain. The crystals also exhibit excellent electro-optic detection which is confirmed by signal-to-noise ratio in the measured range.

The Spatial and Temporal Evolution of the Sadisdorf Li-Sn-(W-Cu) Magmatic-Hydrothermal Greisen and Vein System, Eastern Erzgebirge, Germany

Abstract The Sadisdorf Li-Sn-(W-Cu) prospect in eastern Germany is characterized by vein- and greisen-style mineralization hosted in and around a small granite stock that intruded into a shallow crustal environment. The nature and origin of this mineral system are evaluated in this contribution by a combination of petrography and fluid inclusion studies, complemented by Raman spectroscopy and whole-rock geochemical analyses. The early magmatic-hydrothermal evolution is characterized by a single-phase low-salinity (7.0 ± 4 wt % NaCl equiv), high-temperature (>340°C), CO2-CH4–bearing aqueous fluid, which caused greisen alteration and mineralization within the apical portions of the microgranite porphyry. The bimodal distribution of brine and vapor fluid inclusions, and the formation of a magmatic-hydrothermal breccia associated with the proximal vein mineralization are interpreted to mark the transition from lithostatic to hydrostatic pressure. The vein- and stockwork-style mineralization (main stage) displays lateral zonation, with quartz-cassiterite-wolframite-molybdenite mineral assemblages grading outward into base-metal sulfide-dominated assemblages with increasing distance from the intrusion. Late fluorite-bearing veinlets represent the waning stage in the evolution of the mineral system. The similarity in the homogenization temperature (250°–418°C) of fluid inclusions in quartz, cassiterite, and sphalerite across the Sadisdorf deposit suggests that cooling was not a significant factor in the mineral zonation. Instead, fluid-rock interaction along the fluid path is considered to have controlled this zonation. In contrast to quartz-, cassiterite- and sphalerite-hosted fluid inclusions, which have a salinity of 0.0 to 10.0 wt % NaCl equiv, the fluid inclusions in late fluorite veins that overprint all previous assemblages have a salinity of 0.0 to 3.0 wt % NaCl equiv and homogenize at temperatures of 120° to 270°C, thus indicating cooling with or without admixture of meteoric fluids during the waning stage of the mineral system. The Sadisdorf deposit shares similar characteristics with other deposits in the Erzgebirge region, including a shallow level of emplacement, similar mineralization/alteration styles, and a hydrothermal evolution that includes early-boiling, fluid-rock interaction, and late cooling. In contrast to most systems in the region, both proximal and distal mineralization are well preserved at Sadisdorf. The recognition of such spatial zoning may be a useful criterion for targeting greisen-related Li and Sn resources.

ИДЕНТИФИКАЦИЯ И ВЫЯВЛЕНИЕ ПРИРОДЫ НЕМЕТАЛЛИЧЕСКИХ ВКЛЮЧЕНИЙ В НЕПРЕРЫВНОЛИТОЙ ЗАГОТОВКЕ ИЗ СТАЛИ 26ХГМФ

The article presents data on the identification of inclusions in metal samples of continuously cast blanks. The counting and identification of inclusions was carried out using the automatic particle analyzer EDAX Particle/Phase Analysis Software. The study established the predominant type of non-metallic inclusions. It is shown that a large proportion of inclusions are endogenous and have a steelmaking nature of origin. It is shown that inclusions are unevenly distributed over the section of the cast workpiece, and the axial volumes of the workpiece have the maximum contamination. At the same time, the distribution of oxide and oxysulfide inclusions is opposite, which is associated with the course of liquation processes during solidification.

Non‐destructive quantitative analysis of melt inclusions in extraterrestrial samples: Case study of chassignite via nanoscale X‐ray computed tomography

AbstractEstimation of the composition of planetary rocks and minerals is crucial for understanding their formation processes. In this study, we present the application of X‐ray nano‐computed tomography (nano‐XCT) for non‐destructive three‐dimensional (3‐D) phase analysis and estimation of phase abundances in rare Martian meteorite samples, specifically chassignite Northwest Africa (NWA) 2737. We determined the most suitable laser power for minimizing artifacts and maximizing phase contrast. By utilizing nano‐XCT, we successfully identified and segmented primary phases in the bulk meteorite sample. Additionally, we were able to locate and segment crystallized silicate melt inclusions within the meteorite. The phase abundances in bulk NWA 2737 and within melt inclusions calculated using nano‐XCT were in good agreement with previous studies that used thin section calculations, demonstrating the reliability of nano‐XCT as a non‐destructive alternative for estimating bulk phase abundances in rare samples. This study develops a benchmarking protocol and demonstrates the efficacy of nano‐XCT as a non‐destructive technique for generating an overview of phase distribution and assemblages of melt inclusions within rare samples. Future research can benefit from combining non‐destructive 3‐D phase assemblage estimations with non‐destructive 3‐D chemical analysis techniques to achieve a fully non‐destructive parental magma composition estimation of rare cumulate samples.

Three-Dimensional Imaging of Non-metallic Inclusions in Steel Using Ionoluminescence

Obtaining information on the morphology, size, distribution, and chemical composition of non-metallic inclusions in steel helps control the steel production process and the quality of the steel products. Two-dimensional analysis is commonly used to acquire this information; however, more accurate data can be obtained through three-dimensional analysis, leading to a better control of the quality of steel products and their production process. Currently, several techniques are proposed for the three-dimensional analysis of non-metallic inclusions; however, they are time consuming. Herein, the author presented a method to rapidly obtain three-dimensional images of non-metallic inclusions in steel using ionoluminescence (IL). A three-dimensional image of MgO·Al2O3 spinel inclusions was constructed based on two-dimensional IL images obtained every 10 min during argon–ion bombardment. The proposed IL imaging can cover an oval-shaped area of 1.17 mm × 0.26 mm on the semi-major and in the semi-minor axes, respectively, at a single measurement. Three-dimension images of MgO·Al2O3 spinel inclusions with sizes more than 20 μm can be obtained within 4 hours. Therefore, the IL imaging proposed here can provide a precise and rapid account of the effects of non-metallic inclusions on steel products and the steel production process.

Modelling of microscopic crack initiation behaviour of fretting fatigue based on X-ray micro-computed tomography scan

Fretting fatigue is a particularly destructive form of fatigue failure that has drawn significant attention from researchers. This paper proposes a numerical modelling method based on tomography scan to investigate the impact of inclusions on fretting fatigue crack initiation behaviour. The results reveal that inclusions can affect the crack initiation direction and reduce the initiation lifetime. The difference between the properties of inclusions and matrix leads to local mechanical response mismatch, resulting in local stress, strain, and damage concentration. The mismatch in strain and damage follows a gradient distribution along the thickness as the distribution in these mechanical responses. These could explain why particles closer to the surface are more likely to cause damage. Additionally, the aggregation distribution of inclusions results in merging and connecting local regions with high stress, strain, and damage concentration, ultimately promoting fracture behaviour. Finally, the numerical models are validated with experimental data from fretting fatigue tests. Compared to the homogeneous model, the numerical model that considers inclusions from topography data can more accurately analyse the material damage and provide a more comprehensive understanding of fretting fatigue behaviour.

An Online Monitoring System for In Situ and Real-Time Analyzing of Inclusions within the Molten Metal.

Traditional methods for assessing the cleanliness of liquid metal are characterized by prolonged detection times, delays, and susceptibility to variations in sampling conditions. To address these limitations, an online cleanliness-analyzing system grounded in the method of the electrical sensing zone has been developed. This system facilitates real-time, in situ, and quantitative analysis of inclusion size and amount in liquid metal. Comprising pneumatic, embedded, and host computer modules, the system supports the continuous, online evaluation of metal cleanliness across various metallurgical processes in high-temperature environments. Tests conducted with gallium liquid at 90 °C and aluminum melt at 800 °C have validated the system's ability to precisely and quantitatively detect inclusions in molten metal in real time. The detection procedure is stable and reliable, offering immediate data feedback that effectively captures fluctuations in inclusion amount, thereby meeting the metallurgical industry's demand for real-time analyzing and control of inclusion cleanliness in liquid metal. Additionally, the system was used to analyze inclusion size distribution during the hot-dip galvanizing process. At a zinc melt temperature of 500 °C, it achieved a detection limit of 21 μm, simultaneously providing real-time data on the size and amount distribution of inclusions. This represents a novel strategy for the online monitoring and quality control of zinc slag throughout the hot-dip galvanizing process.

Changes in detrital garnet grain morphology and microtextures during fluvial transport in the Western Carpathians revealed by scanning electron microscopy and 3D model analysis: Implication for paleoenvironmental reconstruction

Siliciclastic grain surfaces preserve an information about mechanical transport effects and/or various chemical processes that the detritus has undergone. Weathering, transport, and diagenesis leave the clear traces that may be used to interpret the paleo-environmental conditions. We aimed to detail surface analysis of detrital garnet by the proven scanning electron microscopy (SEM), X-ray micro-tomography (XRT) and subsequent morphometric analysis of derived 3D surface model. We tracked garnet morphological and surface microtextural changes during fluvial transport in an active Beňatinská voda and Sobranecký potok streams in the Western Carpathians from the place of garnet removal from the host igneous rocks to the last appearance of its fragments in the fluvial sediments. Analysed garnet grains show a range of almost complete solid solution between almandine and grossular (Alm70-73Grs15-19Prp5-6Sps2-3Adr0-3). Precise SEM analysis showed that conchoidal fractures, straight and arcuate steps, crescentic percussion marks and V-shaped cracks are main mechanical fluvial microtextures, whilst 3D surface models derived from XRT provided the information that no relationship between mechanical surface-microtextural development and mineral inclusion distribution exists. Thus, the presence of inclusions and their proximity to the grain surface have no influence on garnet destruction during its fluvial transport. Morphometric variables such as surface roughness and curvatures derived from 3D garnet model can be used to distinguish between mechanical impacts and corrosion-induced depressions. The results related to detritus behaviour in the modern streams are applicable to the ancient fluvial sediment research and can help to correctly reconstruct the paleoenvironmental and paleogeographic conditions in various areas.

Scanning electron microscopy analysis of non-metallic inclusions for making steels with superior mechanical properties

The objective of this novel research was to further understand the type, size and areal distribution of the non-metallic inclusions in bearing steels by applying state-of-the-art scanning electron microscopy (SEM) analysis in order to develop steels with superior properties. Ten samples were taken from bearing steel grade 52100 and analysed by SEM. It was concluded that SEM allows deeper understanding regarding the type, morphology, size, and distribution of the non-metallic inclusions by covering larger sample areas and accurate automatic energy dispersive X-ray microanalysis of the inclusions. While most of the non-metallic inclusions had an equivalent circle diameter (ECD) smaller than 20 µm, the main type of inclusions with ECDs larger than 20 µm were calcium aluminates. As the higher sulphur will tend to create sulphide type of inclusions and the lower sulphur will shift the inclusions towards calcium aluminate oxide types, it is recommended to keep the sulphur content at amounts above threshold that calcium aluminates appear.

Multiscale modelling of particulate composites with spherical inclusions

AbstractThis paper presents a novel and effective strategy for modelling three-dimensional periodic representative volume elements (RVE) of particulate composites. The proposed method aims to generate an RVE that can represent the microstructure of particulate composites with hollow spherical inclusions for homogenization (e.g., deriving the full-field effective elastic properties). The RVE features periodic and randomised geometry suitable for the application of periodic boundary conditions in finite element analysis. A robust algorithm is introduced following the combined theories of Monte Carlo and collision driven molecular dynamics to pack spherical particles in random spatial positions within the RVE. This novel technique can achieve a high particle-matrix volume ratio of up to 50% while still maintaining geometric periodicity across the domain and random distribution of inclusions within the RVE. Another algorithm is established to apply periodic boundary conditions (PBC) to precisely generate full field elastic properties of such microstructures. Furthermore, a user-friendly automatic ABAQUS CAE plug-in tool ‘Gen_PRVE’ is developed to generate three-dimensional RVE of any spherical particulate composite or porous material. Gen_PRVE provides users with a great deal of flexibility to generate Representative Volume Elements (RVEs) with varying side dimensions, sphere sizes, and periodic mesh resolutions. In addition, this tool can be effectively utilized to conduct a rapid mesh convergence study, an RVE size sensitivity study, and investigate the impact of inclusion/matrix volume fraction on the solution. Lastly, examples of these applications are presented.

Primary Progressive Apraxia of Speech Caused by TDP-43: A Case Report.

To introduce the first case in which primary progressive apraxia of speech (PPAOS) is associated with TAR DNA-binding protein 43 (TDP-43) instead of 4-repeat tau. This patient was identified through a postmortem autopsy. Following an initial diagnostic evaluation, he participated in 3 annual research visits during which speech, language, cognitive, and neurologic assessments were administered. Neuroimaging was also acquired. Apraxia of speech was diagnosed at his initial visit with a comprehensive neurologic examination further revealing subtle motor findings in the right hand. At subsequent visits, agrammatic aphasia and motor symptoms consistent with corticobasal syndrome were evident. Cognition and behavior remained relatively intact until advanced stages. FDG-PET revealed hypometabolism in the right temporoparietal cortex and left premotor and motor cortices. There was also low-level signal in the right temporoparietal cortex on tau-PET. A sequence variation in the progranulin gene was identified (GRN c.1A>C, p.Met1). Pathologic diagnosis was TDP-43 Type A with an atypical distribution of inclusions in premotor and motor cortices. This case report demonstrates that TDP-43 Type A inclusions in an atypical distribution can present clinically as PPAOS. The sequence variation in the progranulin gene and asymmetric temporoparietal cortex involvement were the strongest indications of the unusual neuropathophysiology prior to autopsy.

Can Renewed Tensions of Tourist Areas Be Resolved? The Key Issue of Stakeholders’ Alignment

Tensions in tourist areas (over-visiting, waste management, traffic jams, conflicts of use, etc.) raise fundamental questions about sustainable development, the distribution of wealth, social justice, cultural identity and inclusion. Paradoxically, few decisions are taken to resolve these tensions, despite the dissatisfaction of all tourism stakeholders. The aim of this study is to help resolve the tensions in tourism areas by identifying a global method for aligning stakeholders. We conducted 72 interviews with all the tourism stakeholders in two very different tourist areas (Brittany and Bali) and used the concepts of sustainable tourism, stakeholders and strategic alignment. The results show that (1) the stakeholders, whether in favour of tourism development or not, all agree on the need to resolve the tensions in the tourist areas; (2) the obstacles and levers of the stakeholders play a decisive role in their commitment to collectively resolving the tensions in the tourist areas; (3) the existing data on tourist numbers are the subject of debate among the stakeholders and slow down the commitment to concrete action. Our conclusions are encouraging, since tensions in tourist areas constitute a problem like any other, which makes it possible to envisage a global methodology for aligning stakeholders. However, the subject of tourist numbers remains a stumbling block in the project to resolve tourism tensions in these areas. Three avenues of research are proposed to help overcome this dead end: integrating the notion of perceived value into measures of tourist numbers in tourist areas, mobilising participatory science to increase the potential of measures of tourist numbers, and adapting the technological acceptance model to tourist numbers.

Accounting for spatial distribution in mean-field homogenization of particulate composites

Several analytical mean-field homogenization methods, which take into account the particle volume fraction, shape and orientation are readily available to estimate the effective properties of particulate composites. Models have also been proposed to account for the spatial distribution of the particles. The classical Ponte-Castañeda and Willis (PCW) model is based on a parametrization of the statistical distribution law, while the Interaction Direct Derivative (IDD) model associates a matrix cell to each inclusion, representative of close interactions. In the literature, the use of the IDD is commonly reduced to the particular case of the classical Mori and Tanaka (MT) scheme or to the aforementioned PCW model. The present study introduces an original approach to calibrate the IDD model, for 2D linear conductivity, based on representative images of the microstructure. The links between the models and the range of validity of the IDD model are discussed. Besides, an “IDD-based” PCW model and a two-step scheme are proposed for situations where the IDD estimate is inconsistent (lack of major symmetry). Finally, an image analysis method using Voronoï diagrams is implemented to define the cells associated to each inclusion and supply the models. The method is validated by comparisons between the obtained IDD and PCW estimates, the Mori–Tanaka (MT) model and benchmark full-field numerical simulations. Accounting for the inclusion distribution is seen to lead to better estimates, both qualitatively (by capturing anisotropic behaviors due to the sole distribution) and quantitatively. Possible extensions to elastic composites are discussed.

Prediction on the Composition Distribution of Oxide Inclusions in a Tire Cord Steel Billet Using an Integrated Model

Prediction on the Composition Distribution of Oxide Inclusions in a Tire Cord Steel Billet Using an Integrated Model