Channel Segregation Research Articles

Achieving a 35-Plex Tandem Mass Tag Reagent Set through Deuterium Incorporation.

Mass spectrometry-based sample multiplexing with isobaric tags permits the development of high-throughput and precise quantitative biological assays with proteome-wide coverage and minimal missing values. Here, we nearly doubled the multiplexing capability of the TMTpro reagent set to a 35-plex through the incorporation of one deuterium isotope into the reporter group. Substituting deuterium frequently results in suboptimal peak coelution, which can compromise the accuracy of reporter ion-based quantification. To counteract the deuterium effect on quantitation, we implemented a strategy that necessitated the segregation of nondeuterium and deuterium-containing channels into distinct subplexes during normalization procedures, with reassembly through a common bridge channel. This multiplexing strategy of "design independent sub-plexes but acquire together" (DISAT) was used to compare protein expression differences between human cell lines and in a cysteine-profiling (i.e., chemoproteomics) experiment to identify compounds binding to cysteine-113 of Pin1.

Effect of withdrawal rate on freckle formation of large-size directional solidified nickel-based superalloy blades

The freckle formation and distribution in large-size directional solidified nickel-based superalloy blades at different withdrawal rates were investigated. The microstructure of freckles was analyzed by optical microscope (OM), and scanning electron microscope (SEM). The crystallographic orientation in the freckle regions was characterized by electron backscattered diffraction (EBSD). The solute segregation patterns on the surface of freckle regions were obtained by X-ray fluorescence (XRF). Numerical simulations for the temperature field were performed to analyze the mushy zone evolution during directional solidification. The experimental results indicated that the root region is prone to form freckles. The freckle chains were only distributed on the outward surface of the root region at low and middle withdrawal rates, and the inward side was free of freckles. When a high withdrawal rate was applied, a few freckles occurred on the inward side of the root region. The number and length of freckle chains increased as the withdrawal rate increased. The XRF results indicated that channel segregation formed on the surface of the root region. The segregation channels predicted by the macrosegregation simulation agreed well with the experimental observation. The concave or inclined solidification interface increased the propensity for freckle formation.

The morphology features, formation mechanism and elimination of channel segregation in industrial-scale Ti–Nb ingots produced by vacuum arc remelting

In this study, the morphology characteristics and formation mechanism of channel segregation in the industrial-sized Ti–Nb binary ingots produced by vacuum arc remelting (VAR) are researched based on experiments and calculations. The results show that the channel segregation is usually located at the 1/4–3/4 radius of the ingot and the morphology is closely related to the VAR process. The Ti-enriched channel segregation stripes tend to parallel to the ingot centerline and columnar dendrites in steady-state remelting region and hot-top region, respectively, while along the molten pool profile in residual molten pool region. For the first time, the Ti2O3 particles precipitated in the channel segregation were observed, following the orientation relationship of <001>β//<133>Ti2O3 and {11‾0}β//{011‾}Ti2O3 with β matrix in coherent boundary. First-principles calculations evident that the enrichment of Ti-solute tends to decrease the formation enthalpy, and hence makes for the precipitation of Ti2O3 particles. The numerical simulation and the experiment results manifest that the channel segregation originates from the convergence of interdendritic Ti-enriched liquid, resulting in the density inversion between the Ti-enriched initiation site and the surrounding liquid. The density gradient and the solidification rate dominate the growth direction and the radius distribution of the channel segregation. Based on the above, an optimized technique with helium cooling and the external stirring magnetic field was conducted and the channel segregation was eliminated successfully.

A class-specific effect of dysmyelination on the excitability of hippocampal interneurons.

The role of myelination for axonal conduction is well-established in projection neurons but little is known about its significance in GABAergic interneurons. Myelination is discontinuous along interneuron axons and the mechanisms controlling myelin patterning and segregation of ion channels at the nodes of Ranvier have not been elucidated. Protein 4.1B is implicated in the organization of the nodes of Ranvier as a linker between paranodal and juxtaparanodal membrane proteins to the spectrin cytoskeleton. In the present study, 4.1B KO mice are used as a genetic model to analyze the functional role of myelin in Lhx6-positive parvalbumin (PV) and somatostatin (SST) neurons, two major classes of GABAergic neurons in the hippocampus. We show that 4.1B-deficiency induces disruption of juxtaparanodal K+ channel clustering and mislocalization of nodal or heminodal Na+ channels. Strikingly, 4.1B-deficiency causes loss of myelin in GABAergic axons in the hippocampus. In particular, stratum oriens SST cells display severe axonal dysmyelination and a reduced excitability. This reduced excitability is associated with a decrease in occurrence probability of small amplitude synaptic inhibitory events on pyramidal cells. In contrast, stratum pyramidale fast-spiking PV cells do not appear affected. In conclusion, our results indicate a class-specific effect of dysmyelination on the excitability of hippocampal interneurons associated with a functional alteration of inhibitory drive.

Optimization of Channel Segregation-Based Fractional Frequency Reuse for Inter-Cell Interference Coordination in Cellular Ultra-Dense RAN

To cope with ever growing mobile data traffic, we recently proposed a concept of cellular ultra-dense radio access network (RAN). In the cellular ultra-dense RAN, a number of distributed antennas are deployed in the base station (BS) coverage area (cell) and user-clusters are formed to perform small-scale distributed multiuser multi-input multi-output (MU-MIMO) transmission and reception in each user-cluster in parallel using the same frequency resource. We also proposed a decentralized interference coordination (IC) framework to effectively mitigate both intra-cell and inter-cell interferences caused in the cellular ultra-dense RAN. The inter-cell IC adopted in this framework is the fractional frequency reuse (FFR), realized by applying the channel segregation (CS) algorithm, and is called CS-FFR in this paper. CS-FFR divides the available bandwidth into several sub-bands and allocates multiple sub-bands to different cells. In this paper, focusing on the optimization of the CS-FFR, we find by computer simulation the optimum bandwidth division number and the sub-band allocation ratio to maximize the link capacity. We also discuss the convergence speed of CS-FFR in a cellular ultra-dense RAN.

Effects of casting speed on microstructural and tensile properties of Al–Mg–Si alloy fabricated by horizontal and vertical twin-roll casting

For the development of Al–Mg–Si strips with high mechanical performance via twin-roll casting (TRC) technology, it is necessary to understand through comparative analysis of traditional horizontal twin-roll casting (HTRC) and promising vertical twin-roll casting (VTRC) technologies. In this study, two types of Al–Mg–Si alloys (denoted as H-alloy and V-alloy) were fabricated by HTRC and VTRC using different casting speeds (0.69 and 20 m/min, respectively). The microstructural evolution and mechanical properties of the two alloys were comprehensively assessed and compared. To reveal the microstructural characteristics, various techniques including energy-dispersive X-ray spectroscopy (EDS), electron backscatter diffraction (EBSD), texture calculation and differential scanning calorimetry (DSC) were utilized. Center segregation occurred in H-alloy and V-alloy in the form of channel segregation and segregation bands, respectively. Moreover, the texture components of H-alloy showed rolling and shear textures, indicating continuous casting with hot-rolling during HTRC; however, those of V-alloy showed a random texture, indicating the absence of hot-rolling during VTRC. Therefore, the amount of plastic deformation in H-alloy was greater than that in V-alloy, which increased the yield strength through dislocation strengthening. Furthermore, solid-solution strengthening and precipitation strengthening primarily helped improve the strength of V-alloy, whereas pre-existing voids caused premature fracture. Our comparative analysis of the microstructural evolution and tensile properties realized by HTRC and VTRC is anticipated to broaden the understanding of twin-roll-cast strips.

Distinct Mechanisms for Channel Segregation in Ultra-Heavy Advanced Steel Ingots via Numerical Simulation and Experimental Characterization

Distinct Mechanisms for Channel Segregation in Ultra-Heavy Advanced Steel Ingots via Numerical Simulation and Experimental Characterization

Effect of forced convection on the formation of the as-cast structure and macrosegregation of Sn-10wt.% Pb alloy: A numerical study

A series of solidification benchmark experiments based on Sn-10wt.% Pb alloy were performed at the SIMAP Laboratory in Grenoble, France (Hachani et al., 2015) to study the effect of different types of forced convection on the as-cast structure and macrosegregation. Forced convection was achieved by using a traveling magnetic field (TMF). Four cases were investigated: without TMF; TMF in the same direction as natural convection; TMF in the opposite direction as natural convection; and TMF periodically reversed with respect to natural convection. In the current study, a three-phase mixed columnar-equiaxed solidification model was used to “reproduce” the above experiments to understand the flow effect on the as-cast structure formation. The dendrite fragmentation is regarded as the only source of equiaxed grains. Remelting/destruction of equiaxed grains in the superheated melt is considered. The continuous growth of the surviving equiaxed grains and further competition with the as-developed columnar dendrites, leading to columnar-to-equiaxed transition (CET), are included. Except for Case III (i.e., a TMF in the opposite direction as natural convection), satisfactory simulation-experiment agreements in terms of the temperature field, as-cast structure and macrosegregation are obtained for the remaining three cases. Based on the simulation results, it is found that 1) TMF plays an important role in homogenizing the temperature field and promoting the formation of equiaxed grains via fragmentation, consequently facilitating the appearance of CET; 2) TMF tends to generally intensify macrosegregation and increase the number of channel segregations; and 3) the simultaneous solidification/remelting process represents a significant species/energy transport mechanism. Ignoring the remelting of equiaxed grains would lead to an overestimate of the local temperature in the remelting zone. The reason for the mismatch between the simulation and experimental results obtained for Case III is discussed.

Bioelectricity and the Control of Apical Growth in Pollen Tubes

Bioelectricity has been studied since the 18th century in every branch of the tree of life. Bioelectricity is involved in cell growth, proliferation, and behavior, which at a tissue-scale level translates in dramatic tissue rearrangements during embryology and somatic development. Although ion fluxes can be measured in single cells, it is not unanimous that a single cell may create and sustain different bioelectrical states within itself by means of electrochemical nonequilibrium phenomena. We address this possibility, with a focus on the pollen tube as a biological model. Pollen tubes are the subject of intense research given its unique properties, evolutionary streamlined to very fast apical growth and sensitivity to external cues that affect chemotropic responses. Pollen tube's functions rely on conspicuous tip-focused ions dynamics, involving the formation of steep ion gradients, with ion concentration differences over an order of magnitude when compared with the shank cytosol. These gradients are thought to be based on the spatial segregation of ion transporters, channels, and pumps along the cell, creating distinct electrochemical environments at the tip and the shank. But how polarity is generated and maintained is still a matter of debate. In the past we hypothesized that opposing electrochemical forces of depolarization at the tip and hyperpolarization in the shank could create a membrane potential gradient spanning from the tip to the shank that would be part of feedback mechanisms essential to cell polarity in these and likely other cell types. In this study, we review the latest progress on understanding apical growth from the perspective of bioelectricity-driven morphogenesis.

Probing the homogeneous distribution of sodium atoms in silicate glasses

Sodium, silicon, and oxygen—the major constituents of magmatic silicate melts in the Earth's crust and mantle—are also common ingredients in commercial flexible and scratch-proof glasses for advanced optoelectronic devices. The distribution of alkali metal cations in these amorphous networks is known to control their overall strength, flexibility, and chemical resistance. While the exact nature of their distribution remains a longstanding problem in understanding the glass structures, metal cations have often been expected to form heterogeneous nano-scale percolation channels where they have exclusive proximity towards nonbridging oxygens (NBOs; Na–O–Si species). Contrary to this picture, we show that nuclear magnetic resonance correlation spectroscopy between sodium and oxygen atoms demonstrates the presence of bridging oxygens (BOs; Si–O–Si species), as well as NBOs, in the immediate vicinity of sodium atoms. Our results indicate a metal distribution which is more homogeneous than the previously envisaged Modified Random Network (MRN) model, which represents the extreme end of heterogeneity with metal percolation channels encapsulated exclusively by nonbridging oxygens, by placing qualitative limits on the extent of segregation of alkali channels from silica-enriched regions as suggested by the MRN model. A refined structural model of oxide glass is proposed in terms of a “perturbed” metal ion distribution, which features a rather homogeneous metal dispersion with differences in Na affinity towards the bridging and non-bridging oxygen species. Such perturbed alkali distribution may be used to account for the anomalous viscosity of magmatic melts, as well as revealing the origins of pronounced toughness in complex oxide glasses.

Development and benchmarking of numerical model in OpenFOAM® for the prediction of channel segregation during columnar alloy solidification

• Benchmark sn-5 wt%Pb alloy solidification problem is simulated using OpenFOAM solver. • Mesh sensitivity analysis is performed to resolve the flow in channels segregates. • Effect of microsegregation and mushy zone models on channels formation is studied. • Scheil's model predicts more negative and positive segregation than Lever rule. • Inertial drag in mushy zone significantly affects the channel segregates formation. In the past, most of the numerical studies on the prediction of macrosegregation and mesosegregation (e.g. channel type segregation) were performed using in-house codes and commercial software, both of which have limitations such as huge license costs, non-availability for general public research etc. In this study, a dedicated CFD solver is developed in an open-source platform – OpenFOAM® for the prediction and characterization of channel segregates in castings. The solver accounts for the fluid flow, heat transfer, species transport, multiscale segregation, solidification and mushy zone drag phenomena that occur during alloy solidification. The developed solver is extensively validated with the reported benchmarked experimental and numerical results for the sn-Pb alloy solidification. Direct numerical simulations (DNS) are performed to resolve the flow field in and around the channels (which are of mesoscopic length scale) for the first time. It is observed that mesh size ≤ 2 d 2 (secondary dendritic arm spacing) is required to resolve the flow in channels and accurately predict their morphology and locations. Further, the effect of different microsegregation and mushy zone drag models on the segregation and morphology of channel segregates is thoroughly investigated. The predicted extent of negative and positive segregation is found to be more (negative segregation ∼ 7.7 wt%Pb and positive segregation ∼ 18.7 wt%Pb) in Scheil’s microsegregation model compared to Lever rule. Furthermore, the inertial drag in the mushy zone significantly affects the convective transport of solute and thereby the morphology and the number of channel segregates.

Low-Energy Excitations of Skyrmion Crystals in a Centrosymmetric Kondo-Lattice Magnet: Decoupled Spin-Charge Excitations and Nonreciprocity.

We theoretically study spin and charge excitations of skyrmion crystals stabilized by conduction-electron-mediated magnetic interactions via spin-charge coupling in a centrosymmetric Kondo-lattice model by large-scale spin-dynamics simulations combined with the kernel polynomial method. We reveal clear segregation of spin and charge excitation channels and nonreciprocal nature of the spin excitations governed by the Fermi-surface geometry, which are unique to the skyrmion crystals in centrosymmetric itinerant hosts and can be a source of novel physical phenomena.

Comparative investigation on ingot evolution and product quality under different arc distributions during vacuum arc remelting process

The arc characteristics especially the arc distribution of the vacuum arc remelting (VAR) process are closely related to the ingot evolution and consequently the final product quality. Taking segregation defects and solidification quality as the indexes to evaluate the final product quality under different arc distributions, a three-dimensional full-scale transient model for predicting segregation defects is developed in this paper. Local solidification time (LST) and secondary dendrite arm spacing (SDAS) are used to characterize the solidification quality. This model is adopted to predict channel segregation (freckle) and macrosegregation defects during VAR process of Ni-5.8 wt.%Al-15.2 wt.%Ta alloy under several typical arc distributions. The results show that the diffuse arc has the shallowest molten pool among several arc distributions. At the early stage of solidification, the solute enrichment channels formed under the Gaussian and diffuse arc are slender and concentrated, while they are relatively sparse and uneven in thickness under the rotating arc. The value of volume-averaged segregation extent is always the smallest under the diffuse arc and the largest under the Gaussian arc, with final values of 67.53% and 69.66%, respectively. The volume-averaged values of LST and SDAS are relatively the largest under the Gaussian arc, about 1599 s and 209 μm, respectively; and they are the smallest under the diffuse arc, about 1520 s and 206 μm, respectively. In the same process conditions, the product quality of VAR ingots prepared under the diffuse arc is the best, followed by the rotating arc, and the worst under the Gaussian arc.

On the Mechanism of Steel Homogenization via Rare Earth Addition: Experimental Characterization and Numerical Simulation

Abstract Macrosegregation is one of the most typical defects during solidification which greatly limits the mechanical properties of the key steel components. Oxygen and its inclusion have been considered to cause the compositional heterogeneity in solidifying steel besides the thermo-solutal convection. However, it is still not clear how to robustly reduce the oxygen and inclusion and consequently macrosegregation in widely used steels. Here, we reported the mechanism to homogenize the steel via Rare Earth (RE) addition. A series of experimental characterizations of 3-ton bearing steel ingots demonstrated that RE is able to decrease the oxygen content and inclusions to a lower level than the conventional Al-deoxidation process. The common oxide and sulfide can be modified into spherical or ellipsoidal RE2O2S with a dispersed distribution. The multi-component/multi-phase macrosegregation simulations show that the larger size and population of RE2O2S are required to trigger channel segregation in RE steel due to its higher density compared to the alumina-based inclusions. The theoretical calculation reveals that the critical oxygen content in RE steel to eliminate channel segregation is dramatically increased into 20 ppm, which indicates a lower risk of destabilization of mushy zone and initiation of channel segregation in RE steel. In addition, the global macrosegregation severity is reduced in RE steel. Such conclusion is fully validated in larger 9.5-ton and 100-ton steel ingots. In terms of the interaction between inclusion motion, fluid flow, and solidification, this study elucidates the mechanism of RE to reduce macrosegregation for the first time, and highlights an economic, common, and controllable method to fabricate homogenized steel by RE addition.

Insight into the sensitivities of freckles in the directional solidification of single-crystal turbine blades

Freckle, a thermal-solutal-fluid flow induced metallurgical defect, can degrade the mechanical performance of the investment cast nickel-based single-crystal turbine aerofoil. Channel segregation, appearing as channel-liked solute enrichment pattern, is generally considered to be a representative phenomenon in the formation of freckles. The geometrical effect of the intricate curve turbine blade with relevant processing conditions into the freckle mechanism is still unprecedented. In this work, we proposed the Eulerian multiphase thermal-fluid flow model for predicting the freckles (channel segregation) in the representative single crystal turbine blades. The prediction which captures the complex transport phenomena of thermal-solutal convection, solute plumes and segregation profile is in good agreement with the available experimentation. Based upon the thermal-solutal-fluid flow rationalisation of the solidification process, mechanisms proposed provide better understanding of the channel segregation sensitivities to the cooling conditions and geometrical factors. Sensitivity studies verify the mechanisms and give further implication on preventing and even eliminating the freckles.

Three-Dimensional Numerical Simulation and Experimental Investigations of Benchmark Experiment of Sn-10 wt. %Pb Alloy Solidification Under Thermosolutal Convection

Abstract A full three-dimensional (3D) numerical simulation of solidification was carried out for a benchmark experiment on a binary Sn-10 wt. %Pb alloy. The experiment process involves a melting stage, a first holding stage at constant temperature with electromagnetic stirring, setting a mean horizontal temperature difference (second holding stage), and finally solidification stage by decreasing the temperature under a imposed horizontal temperature gradient. The numerical model is applied only to investigate the solidification stage and compared with the measured temperature fields and macrosegregation obtained from the postmortem analysis. A columnar numerical model based on a two-phase volume-averaged approach is used for the numerical simulation, accounting for thermosolutal convection and assuming perfect microscopic mixing (lever rule) in the mushy zone. It demonstrates that such a model is able to predict stratification in the solute from the liquid phase and mushy zone during the solidification. The effect of the sedimentation on macrosegregations and channel segregation or freckles which develop during the solidification stage is also predicted by the model and compared with experimental data. Emphasis is given to the main factors that have a direct effect on the development and morphology of segregated channels, namely, the remelting phenomenon, dendrite fragmentation, and the solidification front instabilities.

Numerical Investigation of Segregation Evolution during the Vacuum Arc Remelting Process of Ni-Based Superalloy Ingots

Segregation defects greatly affect the service performance and working life of castings during the vacuum arc remelting (VAR) process. However, the corresponding research on the prediction of segregation defects is still not comprehensive. Through considering the influence of water-cooled crucible on the electromagnetic field inside an ingot, a full-scale model for the comprehensive prediction of freckles and macrosegregation defects during the VAR process is developed in this paper. The macroscopic solute transport phenomenon and the segregation behavior of Ni-5.8 wt% Al-15.2 wt% Ta alloy are predicted. The results indicate that the freckles are mainly concentrated in the lower region of the ingot. With the growth of the ingot, the solute enrichment channels gradually develop into solute enrichment regions, and the channel segregation evolves into macrosegregation. The Lorentz force mainly affects the flow pattern at the top of the molten pool, while the complex flow of multiple vortices is dominated by thermosolutal buoyancy. The maximum and minimum relative segregation ratio inside the ingot can reach 290% and −90%, respectively, and the positive segregation region accounts for about 79% of the total volume. This paper provides a new perspective for understanding the segregation behavior inside the ingot by studying the segregation evolution during the VAR process.

Groundwater-sourced irrigation and agro-power subsidies: Boon or bane for small/marginal farmers in India?

Growing inequity in access to sustainable irrigation supply services, groundwater and electricity in particular, has become core agendas in many recent global development dialogues on account of food/nutritional security, ensuring on-farm livelihood opportunities, rural poverty alleviation and development. Herein, we aim to present a nation-wide appraisal of eco-environmental and socioeconomic ramifications of subsidizing farm-power services in India, to highlight future requirements to conserve groundwater reserves so as to ensure sustainable irrigation supply services. We adopted a mixed method approach, coupling secondary data analysis (obtained from various governmental archives), with a systematic review of relevant global literature. For the latter, we adopted a multi-stage PRISMA method (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) to summarize observations from post-2000 literature. Our results indicate that, over the years, groundwater has emerged as the mainstay of the irrigation sector in India (via millions of tube/bore wells), replacing surface-water systems (canals). However, unsustainable groundwater drafting has led to (i) significant groundwater drawdowns in most Indian states; (ii) exacerbated greenhouse gas emissions; and (iii) caused extensive soil-water salinization, which impede sustainable agrarian/rural development on long-run. Current literature, however, suggests that, unsustainable groundwater drafting is indulged at policy level only by (i) relaxed groundwater tariffing scheme, and (ii) lucrative agro-power subsidies – collectively which offer the farmers free reign to draft groundwater at will. We reflect on the rise of groundwater market, leading to disproportionate access to groundwater for irrigation, and tragedy of the less-endowed sections of the famring communities. We urge the concerned authorities to devise and implement strategic institutional reforms to bolster the agro-power subsidy delivery mechanisms, and reflect on opportunities of nationwide adoption of feeder channel segregation (FCS) and initiate minimum energy support (MES) schemes. The idea is to make the agro-energy sector more efficient (based on notions of equity, fairness and transparency for all to access the benefits. In the final section we urge the authorities to adopt a systems' thinking approach to identify the key barriers to on-ground implementation of FCS and MES; introduce smart metering system, and above all, incorporate the water-food-energy nexus application in mainstream decision making for irrigation services. The idea is to identify/develop means of resource co-management, identify synergies and trade-off, within a unified framework of irrigation systems’ governance that balances resources supply and demand, without endangering the ecosystem services. We also outline potential research directions; emphasize on need of targeted, process-level investigations with increased case studies, and urge the authorities for improved data dissemination and accessibility.

Experimental Study of the Effect of Intermittent Electromagnetic Stirring on the Columnar-Equiaxed Transition in Sn–10 wt % Pb Alloy Solidification

Abstract Experimental analysis of stratification, electromagnetic stirring (EMS), and solidification were carried out for two solidification experiments for a binary Sn–10 wt % Pb alloy. The objective of this study is to examine the effect of forced convection driven by an intermittent traveling magnetic field on the solidification process. Several aspects were investigated, namely, thermal field, macrostructure, and finally segregation behavior, as well as morphology. The effect of the both thermal and solutal stratification on the intensity of the flow is discussed yet showed that stratification has a stabilizing effect for the flow, which can also slow the convective hydrodynamic movements generated by the buoyancy forces. The consequence of this stratification on macrosegregations and channel segregation, which develop during the solidification period, is experimentally analyzed. EMS by intermittent traveling magnetic promotes the development of the columnar-equiaxed transition mechanism (CET), more particularly the refinement of the grain size. The results illustrate, also, that EMS effectively diminish macrosegregations significantly, while remaining inactive for reducing channels segregation development.

Morphology transition of eutectic carbide assisted by thermoelectric magnetic force during the directional solidification of M2 high-speed steel

ABSTRACT The morphology of eutectic carbide was studied by application of a transverse static magnetic field (TSMF) during the directional solidification of M2 high-speed steel. The results show that the morphology of eutectic carbide changed from lamella to fibre as the magnetic flux density (MFD) increased from 0 to 1 T. The transformation from lamella to fibre has been enhanced by the increasing MFD. Solute elements moved and gathered at a certain region in the mushy zone when imposing a TSMF. In the mushy zones, channel segregations were formed in the samples treated by 0.2 and 0.4 T TSMF. When the MFD increased to 0.8 and 1 T, the channel segregation disappeared. Morphology transition, solute elements movement and formation of channel segregation were attributed to the thermoelectric magnetic force (TEMF). This work provides a new method to control the distribution of carbides in steel assisted by TEMF.