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At present, wire sawing technology is the primary slicing method used for certain brittle materials, including monocrystalline silicon, sapphire, and silicon carbide. The surface quality of the sawn wafers significantly impacts subsequent machining processes, such as grinding and polishing. A theoretical model was developed to predict the amount of material removed per unit length of wire during the slicing of circular workpieces by a wire saw with reciprocating and rocking functions. Experiments were conducted during this study in which crystal ingots were sliced using a multi-wire saw, and the amount of material removed per unit length of wire was determined at different cutting positions on the workpiece cross-section. The surface roughness of each crystal wafer was measured systematically. The experimental results revealed that the surface roughness values measured at different points at the same y-coordinate position on a single wafer were approximately equal. However, the surface roughness was greatest on both the initial and final cutting edges and gradually decreased toward the wafer center. The surface roughness was also greatest for the wafer cut nearest to the new wire side, though it gradually decreased for wafers cut nearer to the center of the workpiece and remained relatively consistent from the middle wafer to the wafer cut nearest to the used wire side. The results also indicated that both the material removed per unit length of wire and the surface roughness of the wafer decreased with increases in the wire speed. The relationship between the material removed per unit length of wire and the surface roughness was approximately linear. When the material removed per unit length of wire was set to 0.00333 mm3/m, the average wafer surface roughness was 0.45 μm. [ABSTRACT FROM AUTHOR]

During electroslag remelting (ESR), high MgO contents are typically added to CaF 2 –CaO–Al 2 O 3 slag to control magnesium content in iron- and nickel-based alloys. The melting temperature and viscosity of ESR slag are pivotal for energy consumption, production efficiency, smooth operation, and ingot quality. However, there is currently a notable scarcity of research on the melting temperature and viscosity of CaF 2 –CaO–Al 2 O 3 –MgO slag with high MgO levels. Thus, the melting temperatures and viscosity of CaF 2 –CaO–Al 2 O 3 –MgO slags with varying MgO contents and CaO/Al 2 O 3 (C/A) ratios were investigated. The results show that as the MgO content increases from 7.83 % to 13.18 %, the final precipitation content of the MgO phase significantly increases, resulting in an increase in the melting temperature from 1306 °C to 1319 °C. With the increase in the C/A ratio from 0.86 to 1.16, the precipitation completion temperatures of the Ca 12 Al 14 F 2 O 32 and MgO phases significantly decrease and the MgAl 2 O 4 phase transforms into the CaO phase. Hence, the melting temperature decreases from 1329 °C to 1314 °C. Further increasing the C/A ratio to 1.40, the final precipitation content of the CaO phase increases, resulting in a decrease in the melting temperature from 1314 °C to 1282 °C. Moreover, as the MgO content and C/A ratio increase, the slag viscosity exhibits different change trends within various temperature ranges. This depends on which of the depolymerization of the slag structure and the precipitation and clustering of the MgO phase has a greater effect on the slag viscosity. [ABSTRACT FROM AUTHOR]

Copyright of Automatisierungstechnik is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To enhance the quality of vacuum arc remelting (VAR) ingots in enterprises, a remelting model and cracking criterion was developed based on simulation and a series of designed experiments to predict the segregation behavior, shrinkage cavity, thermal stress, and cracking tendency of VAR ingot. The remelting model was established by MeltFlow-VAR and Abaqus software. As MeltFlow-VAR cannot calculate the stress, through the secondary development program, the thermal stress of VAR ingot was calculated by introducing the temperature field of VAR process into Abaqus. This model was verified by longitudinal dissection of a 406 kg IN718 alloy VAR ingot. The simulated evolution of molten pool, shrinkage cavity, freckle formation probability and secondary dendrite arm spacing (SDAS) align consistently with the ingot microstructure and experimental results. Combined with thermal stress, the alloy strength at different temperature during cooling and solidification, and failure criterion, a crack criterion was constructed to predict the cracking tendency. Calculating the complete solidification time and cracking tendency of the VAR ingot after melting allows for the determination of the safe demolding time without cracks. This method can be used to explore the effect of different melting parameters, optimize VAR process and improve the quality of VAR production. [ABSTRACT FROM AUTHOR]

Hot tearing, a severe casting defect in magnesium ingots, necessitates the development of constitutive relations to accurately predict the susceptibility of magnesium alloys. In this study, we propose an elastic–viscoplastic (E–V) model for forecasting the hot tearing propensity of Mg–Zn–Cu alloys. Our findings demonstrate that the E–V model yields a hot tearing indicator (HTI) that closely aligns with experimental results compared to the elastic–plastic (E–P) model. Moreover, the E–V model successfully synchronizes with experimental data regarding the initiation temperature for hot tearing. Notably, considering viscoplastic strain leads to higher strain values in the E–V model than those observed in the E–P model. Furthermore, our research highlights that employing an E–V approach is more suitable for predicting hot tearing in magnesium alloys and provides valuable insights into evaluating casting defects within this material system. [ABSTRACT FROM AUTHOR]

The type and morphology of inclusions have an important influence on the properties of high strength oil casing steel. In this paper, laboratory experiments were carried out to investigate the effect of cerium (Ce) alloying and holding time on inclusion modification of oil casing steel. The results show that with the increase of Ce content and the holding time, inclusions gradually changed from irregular shape to ellipsoidal shape. During the modification process, inclusions underwent the following transformations: Ca–Al–O + Al2O3 + Al–Mn–Si–O → Ca–Ce–Al–O + Ce (Mn, Si)–Al–O → CeAlO3 → CaO-Ce2O3 + Ce2O3. When the holding time was 5 minutes, the average size of inclusions decreased from 1.26 to 1.14 μm with Ce content increased from 0 to 77 ppm. Nevertheless, when the holding time was over 20 minutes, the average size of inclusions firstly exhibited a decrease trend while it then showed an increase trend with an increased Ce addition. In addition, the number density of inclusions in molten steel was gradually reduced with Ce content increased from 0 to 77 ppm. For the ingot samples cooled down to room temperature within the furnace, the transformation of inclusions evolved the following characteristics with an increased Ce content in steel: Al2O3 + xCaO·yAl2O3 → Ca–Ce–Al–O → CeAlO3 + CeAl11O18→CeAlO3 → CeAlO3 + Ce2O3. In this study, the optimum modification time and Ce content in Rare Earth Metal (REM) modified high-strength oil casing steel of inclusions was 20 minutes and above 60 ppm, respectively. [ABSTRACT FROM AUTHOR]

In order to optimize the heating schedule before forging and improve the breaking and deformation effects of carbides in high‐speed steel, it is of great significance to study the transformation of M2C carbides at high temperatures. The evolution of carbides in the industrial‐grade American Iron and Steel Institute M35 steel produced by electroslag remelting (ESR) is analyzed and observed using thermodynamic calculations and experimental methods. The results indicate that the carbides in the ESR ingot are mainly MC and M2C, and the microstructures of M2C carbides with the highest volume fraction are lamellar and brain like. As the heating temperature increases and holding time prolongs, the lamellar M2C carbides gradually transform into MC and M6C carbides, accompanied by protrusion, dissolution, separation, and spheroidization of the microstructure, until significant coarsening occurs at 1180 °C for 90 min. The newly transformed carbides are embedded and stacked with each other, occupying the original position of M2C carbides. Based on the theories of Gibbs free energy and atomic diffusion, the evolution mechanism of M2C carbides is discussed. Ultimately, the appropriate heating schedule is proposed, and it is validated by combining the characteristics of carbides after forging. [ABSTRACT FROM AUTHOR]

High-performance magnesium alloys are moving towards a trend of being produced on a large scale and in an integrated manner. The foundational key to their successful production is the high-quality cast ingots. Magnesium alloys produced through the conventional semi-continuous casting process inevitably contain casting defects, which makes it challenging to manufacture high-quality ingots. The integration of external field assisted controlled solidification technology, which combines physical fields such as electromagnetic and ultrasonic fields with traditional semi-continuous casting processes, enables the production of high-quality magnesium alloy ingots characterized by a homogeneous microstructure and absence of cracks. This article mainly summarizes the technical principles of those external field assisted casting process. The focus is on elaborating the refinement mechanism of different types of electromagnetic fields, ultrasonic fields, and combined physical fields during the solidification of magnesium alloys. Finally, the development prospects of producing highquality magnesium alloy ingots through semi-continuous casting under the external field were discussed. [ABSTRACT FROM AUTHOR]

The mechanical properties of high‐speed steel (HSS) are significantly influenced by the distribution of carbides formed during solidification. Despite extensive research, the nonuniform cooling in large ingots remains an area requiring further investigation. In this study, the microstructure inhomogeneity in M42 HSS with a diameter of 330 mm is examined. Models are developed to predict the dissolution of carbide networks during homogenization, achieving a 39% reduction in hardness variation (Δr) between the center and surface. Further improvements are attained through hot forging and rolling, leading to the fragmentation of the carbide network into a banded structure. Additionally, a detailed carbide tip dissolution model is established, providing a reliable basis for optimizing annealing processes. As a result, the carbide distribution converges significantly, with hardness variations reduced by 88% to only 0.3 hardness Rockwell C scale, showcasing substantial enhancement in material homogeneity. [ABSTRACT FROM AUTHOR]

Currently, bismuth telluride-based zone-melted ingots dominate the commercial thermoelectric (TE) market. However, bismuth telluride-based zone-melted ingots with a layered lattice structure are brittle, posing challenges for their application in miniature devices. Their polycrystalline alloys have robust mechanical strength. However, the electrical conductivity of a p -type polycrystalline BiSbTe alloy bulk deteriorates. In the current study, the Bi 0.46 Sb 1.54 Te 3 powder was from crushed zone-melted ingots. Large-sized polycrystalline (CuO) x Bi 0.46 Sb 1.54 Te 3 (x = 0, 0.003, 0.01, 0.03 and 0.1) bulks were prepared via the hot-pressing method under 65 MPa at 510°C for 15 min. The electrical conductivity was improved remarkably by the acceptor doping effect. The bipolar effect of the Seebeck coefficient and thermal conductivity at high temperatures was suppressed significantly due to increased majority carrier centration and enlarged bandgaps. Consequently, their TE performance (the dimensionless TE figure of merit, ZT) was significantly improved and the ZT max and ZT ave reached 1.4 and 1.27, respectively. [ABSTRACT FROM AUTHOR]

By analyzing element segregation and dendritic growth kinetics in combination with microstructure observation and thermodynamic calculation, the influence mechanism of vanadium addition on the dendritic structure and precipitated phase in 30Cr15Mo1N ingots was elucidated. With vanadium addition, the carbonitride types in 30Cr15Mo1N ingots include lamellar M23(C,N)6, globular M2(C,N), and blocky M(C,N). The as-cast structure of the 30Cr15Mo1N ingot is divided into two parts: the dendritic structure, which is mainly composed of martensite and residual austenite, and the interdendritic region, which is primarily composed of precipitated phases like proeutectoid ferrite and carbonitrides. On the one hand, increasing the vanadium content can reduce the amount of martensite and residual austenite in the ingot by suppressing the growth of dendrites and reducing the size of dendrites. On the other hand, the amount of proeutectoid ferrite in the 30Cr15Mo1N ingots increased with an increase in vanadium content and distance from the center due to element segregation in the residual molten steel of the interdendritic region. Under the combined effect of element segregation in the interdendritic region and restricted dendritic growth, the size of carbonitrides showed an increasing trend with increasing the vanadium content. [ABSTRACT FROM AUTHOR]

Research into the processability of NiTiHf high-temperature shape memory alloys (HTSMAs) via laser powder bed fusion (LPBF) is limited; nevertheless, these alloys show promise for applications in extreme environments. This study aims to address this limitation by investigating the printability of four NiTiHf alloys with varying Hf content (1, 2, 15, and 20 at. %) to assess their suitability for LPBF applications. Solidification cracking is one of the main limiting factors in LPBF processes, which occurs during the final stage of solidification. To investigate the effect of alloy composition on printability, this study focuses on this defect via a combination of computational modeling and experimental validation. To this end, solidification cracking susceptibility is calculated as Kou's index and Scheil–Gulliver model, implemented in Thermo-Calc/2022a software. An innovative powder-free experimental method through laser remelting was conducted on bare NiTiHf ingots to validate the parameter impacts of the LPBF process. The result is the processability window with no cracking likelihood under diverse LPBF conditions, including laser power and scan speed. This comprehensive investigation enhances our understanding of the processability challenges and opportunities for NiTiHf HTSMAs in advanced engineering applications. [ABSTRACT FROM AUTHOR]

Based on the thermal compression stress-strain curves and three-dimensional processing maps of the homogenized Mg-8.5Gd-2.5Y-1.5Zn-0.5Zr (wt%) alloy in our previous published work, we performed a comprehensive investigation to assess the influence of multi-directional forging parameter (i.e. per-pass reduction, pass number and temperature) on the strain uniformity of large-scale forged part by finite element simulation. The results indicate that compared to forging temperature and pass reduction, the pass number of deformation significantly influences the strain uniformity. The optimal forging parameters for a large-scale ingot with 430 mm in diameter and 440 mm in height were obtained, i.e., the forging temperature of 450 °C, pass reduction of 40%, pass number of 5 and forging speed of 10 mm/s. Finally, a large-scale forged part with the diameter of 900 mm and the height of 100 mm was successfully produced under the optimal forming condition. The average grain sizes of edge and center regions of the forged part are (4.08 ± 3.25) µm and (5.58 ± 2.19) µm, respectively, exhibiting a small microstructure difference. The properties are relatively uniform, with the tensile strength differences at each position being less than 20 MPa. [ABSTRACT FROM AUTHOR]

One of the characteristic features of PbTe is an uncommon growth of bandgap with increasing temperature, which is quite opposite to the bandgap behavior of the semiconductors commonly used in electronics, for example, Si, Ge, GaAs, and InSb. This specificity allows one to increase the operating temperature of photodiodes fabricated using PbTe up to about 150 K. At the first stage of development, we prepared infrared (IR) photodiodes on the base of bulk single crystalline PbTe. To this end, the ingots with a diameter of about 40 mm were grown by the Czochralski technique. Then, the PbTe p–n junctions were fabricated by using indium donor diffusion to diffuse indium into the PbTe samples. Current–voltage and capacitance–voltage characteristics and spectral detectivity were measured over a wide temperature range and analyzed. The dark saturation current density at T = 100 K was of the order of 10−7 A/cm2. Finally, the unique solid-state multi-stage thermoelectric cooler operated at temperatures up to 150 K was developed. The present study would pave the way to creating a module for efficient photodetection in the mid-wave IR range combining two solid-state devices, namely, the p–n photodiode and thermoelectric cooler, while the latter supports the former. [ABSTRACT FROM AUTHOR]

The electron beam cold hearth melting (EBCHM) process is one of the key processes for titanium alloy production. However, EBCHM is prone to cause elemental volatilization and segregation during the melting of aluminum-containing titanium alloys such as Ti-6wt%Al-4wt%V. To gain deeper insights into the physical and chemical phenomena occurring during the EBCHM process, this paper establishes melting process models for the Ti-6wt%Al-4wt%V titanium alloy in a crystallizer with multiple overflow inlets. It examines the evolution of melt pool morphology, flow dynamics, heat transfer, and mass transfer during the casting process. The results indicate that the design of multi-overflow inlets can effectively suppress the longitudinal development of impact pits within the melt pool, thereby preventing the formation of solidification defects such as leaks in the melt. Concurrently, the diversion effect of multi-overflow inlets significantly enhances the elemental homogeneity within the melt pool. At a casting speed of 20 mm/min and a casting temperature of 2273 K, compared to a single overflow inlet, the design with three overflow inlets can reduce the depth of thermal impact pits within the crystallizer by 132 mm and decrease the maximum concentration difference in the Al element within the crystallizer by 0.933 wt.%. The aforementioned simulation results provide a theoretical basis for the control of metallurgical and solidification defects in large-scale titanium alloy ingots. [ABSTRACT FROM AUTHOR]

Bi 2 Te 3 -based crystal ingots produced by zone melting (ZM) are the most widely used materials to manufacture commercial thermoelectric (TE) devices. However, the poor mechanical properties of such crystalline materials limit the production of small-scale devices. While processability can be improved by powder metallurgy (PM), it also leads to the deterioration of the TE properties due to the donor-like effect of the introduced defects and grain boundaries. Thus, additional efforts towards re-optimizing doping are required. Here, we report a PM method to improve the mechanical properties of Bi 2 Te 3 -based TE materials through the crushing and hot pressing of Bi 2 Te 3 ingots obtained by ZM. Besides, we demonstrate the TE properties of n-type Bi 2 Te 2.7 Se 0.3 (BTS) to be remarkably improved by Cu doping, which enables optimization of the carrier concentration and enhances phonon scattering at heterointerphases thus increasing the Seebeck coefficient and reducing thermal conductivity. Overall, optimized materials reach dimensionless TE figures of merit (ZT) up to 1.16 at 408 K, i.e. 45% higher than that of state-of-the-art BTS, and an average ZT value of 1.08 in the temperature range of 300–473 K. [ABSTRACT FROM AUTHOR]

In this study, 6201 Al–Mg–Si cast ingots were investigated to determine the influence of total iron and silicon contents and homogenization on their microstructure and performance, including electrical and creep resistance. The tests included scanning electron microscopy, electron back scatter diffraction, and X-ray diffraction. The results showed that an increase in the total Fe and Si contents refined the microstructure, increased the weight of the ∑3 twin boundaries, and decreased the texture index FCGB in the initial Al–Mg–Si cast ingots. With increasing homogenization treatment time, the electrical conductivity (EC) in all three groups of homogenized ingots first decreased significantly (within 4 h) and then remained relatively stable. The increase in the total Fe and Si contents resulted in a decrease in the EC and an increase in the hardness of the as-homogenized cast ingot samples. The improvement in the EC of the initial and as-homogenized cast ingots was due to the high content of low-angle grain boundaries and strong Cube texture. The room-temperature creep resistance of the as-homogenized cast ingots was improved by high Fe and Si contents. The texture index FCGB and orientation streamline approach were determined to be powerful indicators for distinguishing and describing texture evolution during the homogenization of cast ingots with various chemical compositions. [ABSTRACT FROM AUTHOR]

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Li metal batteries have been widely expected to break the energy‐density limits of current Li‐ion batteries, showing impressive prospects for the next‐generation electrochemical energy storage system. Although much progress has been achieved in stabilizing the Li metal anode, the current Li electrode still lacks efficiency and safety. Moreover, a practical Li metal battery requires a thickness‐controllable Li electrode to maximally balance the energy density and stability. However, due to the stickiness and fragile nature of Li metal, manufacturing Li ingot into thin electrodes from conventional approaches has historically remained challenging, limiting the sufficient utilization of energy density in Li metal batteries. Aiming at the practical application of Li metal anode, the current issues and their initiation mechanism are comprehensively summarized from the stability and processability perspectives. Recent advances in robust and ultra‐thin Li metal anode are outlined from methodology innovation to provide an overall insight. Finally, challenges and prospective developments regarding this burgeoning field are critically discussed to afford future outlooks. With the development of advanced processing and modification technology, we are optimistic that a truly great leap will be achieved in the foreseeable future toward the industrial application of Li metal batteries. [ABSTRACT FROM AUTHOR]

In this work, a novel internal heat absorption technology using inorganic material rods is employed during the solidification process of steel ingots, aiming to control their solidification and improve the quality of the final product. The study investigates the effect of the insertion depth of inorganic materials on the solidification microstructure and macrosegregation of 2.5-ton 42CrMo ingots. The mechanical properties of samples from the product are also tested. A numerical simulation model for casting 2.5-ton ingots is established and implemented in Ansys Fluent fluid simulation software, with inorganic material rods set at different preset depths. The simulation explores the physical processes of the melting and floating of inorganic materials in molten steel, as well as their effects on the temperature and flow fields of the material. The results show that deeper insertion of inorganic materials (200 mm from the hot top) reduces the tendency for macrosegregation compared to that at the insertion depth of 100 mm. Specifically, the positive segregation area decreases by 10.35%, while the negative segregation area decreases by 15.32%. Moreover, deeper insertion results in a significant refinement of the solidification microstructure, ultimately enhancing the mechanical properties of the products machined from the ingots (i.e., the yield strength increased by 4.7%). The numerical simulation results indicate that as the placement depth of inorganic materials in the ingot mold increases, the cooling effect becomes more significant, the flow area of molten steel initiated by the inorganic materials expands, and the linear velocity of the double-circle flow increases. This further explains why the solidification quality of the ingots improves with the increasing placement depth of inorganic materials. [ABSTRACT FROM AUTHOR]

Thermoelectric cooling has gained much attention due to its significant application in 5G communication chip cooling. Enhancing the performance of thermoelectric cooling devices is an imminent and pressing concern. Applying the same material for both n‐type and p‐type components can promote the compatibility of thermoelectric cooling module due to their similar mechanical properties. This work focuses on the development of thermoelectric cooling module based on n‐type and p‐type PbTe ingots. The high ZT values near room temperature are achieved through fabricating PbTe ingots. This approach substantially enhances the carrier mobility by minimizing charge carrier scattering at grain boundaries compared to polycrystals. These optimized ingots are then utilized to construct a thermoelectric cooling device consisting of seven pairs of thermoelectric couples, which achieves a maximum cooling temperature difference of ≈14 K at room temperature and ≈28 K at 350 K. This study offers fresh insights into the development of thermoelectric cooling module using PbTe‐based materials. [ABSTRACT FROM AUTHOR]

This paper presents experimental results concerning the one-step preparation of cast divanadium nitride and aluminum oxynitride (AlON) by high-temperature synthesis under 5 MPa of N 2 from green mixtures containing vanadium oxide, aluminum, and aluminum nitride. It was shown that the mixtures with a wide range of component ratios are capable to burn with the temperature exceeding the melting point of the final products, divanadium nitride and aluminum oxynitride, that makes it possible to obtain them in the form of a melt with subsequent separation of vanadium nitride (lower ingot) and aluminum oxynitride (upper ingot). The resulting products had no cohesion and were easily separated from each other. Variation in the content of aluminum nitride in the charge markedly affected the synthesis process, phase composition, and microstructure of the target products. The content of excess aluminum nitride in the starting mixture α = 10% was found to be optimum on a yield/composition of the target products. [ABSTRACT FROM AUTHOR]

High-purity copper is essential for fabricating advanced microelectronic devices, particularly integrated circuit interconnects. As the industry increasingly emphasizes scalable and efficient purification methods, this study investigates the multi-physics interactions during the semi-continuous directional solidification process, utilizing a Cu-1 wt.%Ag model alloy. Coupled simulation calculations examine the spatial distribution patterns of the impurity element silver (Ag) within semi-continuously solidified ingots under varying pulling rates and melt temperatures. The objective is to provide technical insights into the utilization of the semi-continuous directional solidification method for high-purity copper purification. The findings reveal that increasing the pulling rate and melt temperature leads to a downward shift in the solid–liquid interface relative to the mold top during processing. Alongside the primary clockwise vortex flow, a secondary weak vortex emerges near the solid–liquid interface, facilitating the migration of the impurity element Ag toward the central axis and amplifying radial impurity fluctuations. Furthermore, diverse pulling rates and melt temperature conditions unveil a consistent trend along the ingot's height, which is characterized by an initial increase in average Ag content, followed by stabilization and then a rapid ascent during the late stage of solidification, with higher pulling rates and melt temperatures expediting this rapid ascent. Leveraging these insights, a validation experiment using 4N-grade recycled copper in a small-scale setup demonstrates the effectiveness of the semi-continuous directional solidification process for high-purity copper production, with copper samples extracted at 1/4 and 3/4 ingot heights achieving a 5N purity level of 99.9994 wt.% and 99.9993 wt.%, respectively. [ABSTRACT FROM AUTHOR]

Herein, the control of steel composition and evolution of inclusions during the electroslag remelting (ESR) of NiCrMoV high‐strength steel are investigated by laboratory experiments and thermodynamic calculations. The effects of slag systems, atmosphere protection, and surface quality of the consumable electrode are discussed. Results show that slag containing 5% TiO2 and 2% SiO2 is beneficial for controlling Ti and Si losses in steel during the ESR. Using argon gas protection reduces the total oxygen (TO) and nitrogen contents in ESR ingots and improves steel cleanliness, while it has little influence on the types of inclusions. The oxide scales on the electrode surface lead to the reoxidation of liquid steel during the ESR. The TO content increases to 113 ppm and Si, Ti, Als, and Mn contents in ESR ingots are considerably reduced. The inclusions are transformed from Al2O3–CaO–TiOx–MgO to MnO–SiO2–Al2O3–TiOx. Thermodynamic calculations reveal that the decrease in temperature promotes the precipitation of Ca2Ti2O5 and Ca2Ti2O6 in inclusions. As the oxygen content from reoxidation increases, the formation of SiO2 and MnO in inclusions in ESR ingots is promoted. Appropriate process parameters are proposed to control the composition and cleanliness of steel during the ESR. [ABSTRACT FROM AUTHOR]

The electron beam cold hearth melting (EBCHM) process is one of the key processes for titanium alloy production. The unique characteristic of this pyrometallurgy process is the application of the cold hearth, which is responsible for controlling the Low-Density Inclusions (LDIs) and High-Density Inclusions (HDIs) in the melt. As a key process of inclusion removal, the information such as melt residence time in the cold hearth is directly related to the control of metallurgical defects in the ingot, and may also affect the composition distribution of the ingot. In this paper, the details for the physical phenomena, namely the evolution of the pool, the evolution of the flow, and the evolution of the component in the cold hearth during EBCHM are investigated using a modified multi-physical numerical model. The effects of melting temperature and melting speed on these phenomena were investigated. The purpose is to provide more fundamental knowledge and to further enhance the applications of EBCHM for more titanium alloys. [ABSTRACT FROM AUTHOR]

In response to the rail head line defect in the production process of hundred-meter rails, through inspection and analysis of rail tracks with line defects, theoretical calculations of rolling deformation, and on-site industrial trials, it is clarified that the rail head line defect is caused by defects such as cracks in the ingot corners, slab furnace marks, and scratches during rolling. Correspondingly, effective measures to reduce the occurrence of rail head line defects are proposed for each of the three defect causes. [ABSTRACT FROM AUTHOR]

A high alloying degree is required for AgCuNilnSn series electrical contact materials and it is necessary to perform homogenizing heat treatment on the alloy ingot to eliminate non-equilibrium phases with low melting-point and dendritic segregation in the ingot microstructure. The traditional "trial-and- error" method for finding the optimal process parameters for heat treatment has the defects ofhuge number of experiments, long cycle and low efficiency. A high-throughput preparation method for homogenizing heat treatment with gradient temperature field was proposed in this paper to screen the optimal treatment conditions for Ag-6Cu-0.5Ni-0.5In-0.5Sn. The experimental results show the maximum hardness of the alloy obtained after 75% plastic deformation by gradient homogenization heat treatment is 168.7, a value corresponding to the optimum homogenization heat treatment temperature of 608.13 °C/1 h. Under the optimal annealing conditions, the volume of grains and the second phase are small, and the distribution of point-like second phase dispersion is more and uniform. At this point, the strengthening effects both from fine grains and dispersions are most significant. [ABSTRACT FROM AUTHOR]

The process of precipitation of Al3Zr particles in cast Al–(0.25–0.4) wt % Zr alloys manufactured by the induction casting method is studied. The effect of zirconium concentration on the structural parameters, hardness, and specific electrical resistance (SER) of cast alloys is investigated. The dependences of hardness and SER on the time of cast alloys annealing at 500°C are plotted. The parameters of the Johnson–Mehl–Avrami–Kolmogorov equation for alloys with different Zr content are determined. The optimal regimes of cast ingot aging are found. Fine wires with ∅0.3 mm are manufactured by the drawing method; their strength, SER, and hardness are studied in the initial state and after heat treatment. The tests of thermal stability of wires are carried out according to the state standard GOST R MEK 62004–2014. [ABSTRACT FROM AUTHOR]

A comprehensive investigation, encompassing microstructural analysis of the subsurface and bulk regions, along with tensile testing near the solidus temperature in the range of 520–580 °C and with two strain rates (10–4 and 10–3 s−1), was conducted on two AA5182 alloy ingots (A and B) cast at casting speeds of 60 and 75 mm ∙ min−1, respectively. Microstructural analysis revealed an equiaxed grain structure throughout Ingot A, whereas Ingot B transitioned from an equiaxed structure in the subsurface to a columnar grain structure in the bulk region. Regarding intermetallic phases, Ingot A showed predominant Al6(Fe,Mn), whereas Ingot B exhibited a high amount of needle-like Al3Fe. Consequently, Ingot A exhibited superior semisolid tensile properties compared to Ingot B at the given test temperatures. The difference between the two ingots became pronounced at the low strain rate of 10–4 s−1, with the brittle temperature range (BTR) values of Ingot B higher than those of Ingot A. An assessment of the hot-tearing susceptibility (HTS) using the BTR criterion revealed that the HTS of Ingot B was higher than that of Ingot A, confirmed by the occurrence of a large transverse macrocrack during the direct-chill casting of Ingot B. [ABSTRACT FROM AUTHOR]

In this study, to clarify the evolution mechanism of dendrite structure and shrinkage porosity in 30Cr15Mo1N ingots under varying pouring rates, the changes in cooling rate, temperature gradient, secondary dendrite arm spacing (SDAS), columnar to equiaxed transition (CET), and area of shrinkage porosity with pouring rate are investigated. The cooling rate and temperature gradient calculated by using the ProCAST software increase with the pouring rate, leading to a great solidification rate. As a result, the SDAS decreases and the position of CET moves toward the center of 30Cr15Mo1N ingot. Additionally, the area proportion of shrinkage porosity increases with the increase in pouring rate. This phenomenon can be mainly due to the less overlap between columnar dendrite and higher permeability with the larger SDAS, which are conducive to the feeding of the molten steel. In addition, the delayed formation of semi‐solidified shell at the top of the ingot at low pouring rate minimizes the impact of solid contraction on the surface sink, which results in a flatter top surface of the ingot at low pouring rate. [ABSTRACT FROM AUTHOR]

To investigate the influence of rolling passes on the internal quality during high‐temperature reduction pretreatment (HTRP), three cast ingots with identical total reduction but varying numbers of rolling passes are prepared. The 3D distribution, size, and quantity of defects are analyzed using ultrasonic nondestructive microscopy. The effect of rolling passes on defect healing is studied, with macrostructure, microstructure, and grain size analysis aided by finite element software. In contrast to the three‐pass HTRP, the one‐pass HTRP demonstrates a diminishment of 7% in defect dimensions and a notable decline of 66% in the quantity of defects. The results reveal that increasing the number of rolling passes leads to a deterioration in internal quality of the slab. Reducing the number of rolling passes improves internal strain penetration, facilitates the recrystallization process, and enhances the microstructure uniformity, ultimately improving the internal quality. [ABSTRACT FROM AUTHOR]

The present work is based on the numerical investigation of thermal stress and the dislocation density of the directional solidification (DS) grown multi‐crystalline silicon (mc‐Si) ingot. The heat exchanger block (HEB) plays the main role in the growth process, which decides the thermal stress and melt‐crystal interface of the mc‐Si ingot. The conventional furnace is modified to increase the quality of the mc‐Si ingot. The modification on the conventional furnace is done in the insulation block replaced by 1/3rd of the HEB. The HEB enhances the huge amount of heat extraction from the bottom of the crucible. The von Mises stress, dislocation density, and thermal gradient are analyzed. The thermal stress is reduced by the low thermal gradient influenced by the modified HEB. The modified HEB reduces the von Mises stress and dislocation density. The modified furnace system overcomes the conventional case ingot. The result shows that the modified furnace grown mc‐Si ingot improves the efficiency of the solar cell. [ABSTRACT FROM AUTHOR]

Infrared analysis reveals the presence of interwoven inclusions, primarily comprised of silicon nitride and silicon carbide, in the casting process of monocrystalline silicon ingots. This study investigates how the longitudinal temperature gradient affects the removal of inclusions during the casting of monocrystalline silicon ingots through simulations and comparative experiments. Two monocrystalline silicon ingots were cast, each using different longitudinal temperature gradients: one employing smaller gradients and the other conventional gradients. CGSim (Version Basic CGSim 23.1) simulation software was utilized to analyze the melt flow and temperature distribution during the growth process of quasi–monocrystalline silicon ingots. The findings indicate that smaller longitudinal temperature gradients lead to a more robust upward flow of molten silicon at the solid–liquid interface, effectively carrying impurities away from this interface and preventing their inclusion formation. Analysis of experimental photoluminescence and IR results reveals that although inclusions may not be observed, impurities persist but are gradually displaced to the top of the silicon melt through a stable growth process. [ABSTRACT FROM AUTHOR]

Achieving uniform grain size in ingots is challenging in traditional direct chill (DC) casting. The thermal conditions during solidification often result in smaller grain size at the edge of the ingot compared to the center, leading to grain size inhomogeneity even in centimeter-scale samples. In this study, a low-flow pouring technique with the addition of grain refiner is employed to create similar thermal conditions from the edge to the center of the ingot during solidification, resulting in a homogeneous ingot. The grain size at the center of the prepared ingot consistently matches it at the edge. Finite element analysis confirms that low-flow pouring provides suitable thermal conditions for ensuring homogenous grains. Additionally, based on experimental results, a novel analytical model is proposed to precisely identify all active nucleation substrates. The grain size predicted by the proposed model aligns well with the experimental results, outperforming previous models. Our experimental and analytical results provide valuable guidance for the production of homogeneous ingots on an industrial scale. [ABSTRACT FROM AUTHOR]

The non-oriented Fe-6.5wt.%Si alloy cast strip with a width of 100 mm and a thickness of 1.7 mm was prepared by the top side-pouring twin-roll-casting (TSTRC) process. The surface quality of the air-cooled and water-cooled cast strip was good. Compared with the Fe-6.5wt.%Si alloy ingot, the Fe-6.5wt.%Si alloy cast strip has a fine solidification structure and exhibits certain plasticity at room temperature. Microhardness, XRD, and TEM investigated the ordered structure and degree of Fe-6.5wt.%Si alloys prepared by three different cooling methods. The results show that the Fe-6.5wt.%Si alloy ingot prepared by the standard method has many B2-ordered phases and D03-ordered phases, and the order degree is high. The Fe-6.5wt.%Si alloy cast strip prepared by the TSTRC process has a low degree of order and only contains a small B2-ordered phase. The faster cooling rate effectively inhibits the formation of the D03-ordered phase and B2-ordered phase. The growth of the ordered phase also reduces the reverse domain boundary energy, reduces the motion resistance of superdislocations, and increases its mobility, thereby improving the room temperature plasticity of Fe-6.5wt.%Si alloy cast strips. [ABSTRACT FROM AUTHOR]

Glass sagging is a subsequent process to the CVD process used for large‐size and high‐purity silica glass synthesis. Physical phenomena taking place in this process are complicated which need an in‐depth understanding for better control. In this paper, a comprehensive study is conducted for the sagging process using a level‐set and enthalpy‐porosity coupled model. With this model, the deforming behavior of glass ingot and evolution of OH uniformly distributed region are well predicted. Then, two performance indices (the effective yield rate and maximum extension radius of OH uniformly distributed region) are proposed based on different applications, and important factors, including geometrical parameters (the ingot initial length, crucible diameter and pedestal height) and operating parameter (the heater power allocation scheme), are explored for their effects on the two indices. The orthogonal test design method is adopted to further determine the collective effects of the four factors. According to the range analysis results, the initial ingot length has the greatest effect, while the crucible diameter has the least effect on the effective yield rate; and for the maximum extension radius, the crucible diameter becomes the major factor, while the pedestal height is the most insensitive factor. The corresponding optimal schemes are proposed for the two indices finally, which are believed to provide useful guidance for improving the sagging process. [ABSTRACT FROM AUTHOR]

Herein, the Ce‐containing inclusions in8Cr4Mo4V‐bearing steel are taken as the research objective to develop anumerical model of inclusions motions behavior. The model is validated bycomparing it with experimental data. During the vacuum arc remelting process, inclusions move along the molten pool's surface toward the edge under theaction of resultant force, and finally become trapped within the mushy zone. Notably, the majority of inclusions are concentrated near the ingot's edge, andtheir numbers decrease as the radial distance decreases. Furthermore, thenumber of Ce‐Mg‐O‐S inclusions exceeds that of Ce‐O‐S inclusions near the ingot's center. This discrepancy arises due to lower density of Ce‐Mg‐O‐Sinclusions, which exhibits a stronger tendency to migrate toward the moltenpool's center. Additionally, as the inclusion diameter increases, buoyancy forceacting on the inclusions increases, resulting in a higher number of inclusionsnear the ingot's center. When considering the effect of gas cooling, theinclusion distribution becomes more pronounced at the ingot's edge. This isattributed to the enhanced cooling capacity of the mold resulting in the decreasing of molten pool depth and consequently a stronger ability of themushy zone to trap inclusions. [ABSTRACT FROM AUTHOR]

Previous research revealed that the quality of the ingots produced by different primary or secondary alloy suppliers can differ remarkably. In this way, the quality of the liquid metal and the castings produced from it can be affected by the impurity content of the ingots used as charge material. In this work, a modified reduced pressure test (RPT) technique, which is based on the remelting of samples extracted from ingots, was applied to investigate the quality of primary AlSi9Mn ingots made by horizontal direct-chill (HDC) casting and gravity casting techniques. For the evaluation of metal quality, image analysis of the cross sections was applied. Pore area fraction, number density, normalized bifilm index, and normalized total pore perimeter were determined, and the relationships between the different metrics were analyzed. The results were compared with the melt quality assessment of the as-melted batches made from the ingots. Solidification simulations, thermal analysis, and microstructural investigations were conducted to investigate the solidification conditions of traditional and remelted RPT samples. Based on the results, the HDC cast ingots possess lower oxide and gas concentrations, which can be traced back to the differences in the melt preparation and casting technologies of the ingots. The comparison of the parameters evaluated by image analysis revealed that there is a strong linear relationship between normalized bifilm index and normalized total pore perimeter. The possible sources of error in ingot quality evaluation are highlighted. [ABSTRACT FROM AUTHOR]

This study gives the element compositions and Pb isotope ratios of three lead ingots and three bronze artefacts unearthed from Yinxu, Anyang, Henan province, and two lead vessels from Zhengxiaozhuang tomb, Anhui province, China. The results of composition analysis show that three lead ingots in Yinxu may be the primary product of lead smelting. The lead wares unearthed in Zhengxiaozhuang tomb could be a kind of Mingqi‐funerary replicas. The results of Pb isotope analysis indicate that the culture exchanges between the Central Plains and the Jianghuai area in the late Shang dynasty. The decrease of bronzes with the highly radiogenic lead is consistent with the increase of Pb content in Yinxu bronzes simultaneously, which could be related to the change of lead source. [ABSTRACT FROM AUTHOR]

Dental alloys based on Co or Ni are commonly used in dentistry to fabricate dental prostheses, including crowns, bridges, and partial dentures, but even though both alloys are highly biocompatible, some patients may experience allergic reactions to nickel. This comparative study investigated the behavior of two dental alloys in the oral cavity, analyzing their microstructure, corrosion behavior, elastic modulus, hardness, and tensile strength for ingot and cast crowns. The microstructures of commercial Ni-Cr and Co-Cr samples were analyzed using optical microscopy, scanning electron microscopy (SEM), and X-Ray Diffraction (XRD); elastic modulus and corrosion behavior were determined after immersing the samples in artificial saliva. Ni-Cr alloy has a corrosion potential more negative than Co-Cr alloy; this means that the first alloy is more likely to undergo corrosion than the second alloy. Ni-Cr sample with a higher elastic modulus is generally more rigid and less flexible than Co-Cr sample with a lower elastic modulus. The analyzed Co-Cr alloy has a higher resistance to corrosion, resulting in a more esthetically pleasing and longer-lasting restoration. The Co-Cr alloy also has a lower density than the Ni-Cr alloy, which, combined with its strength-to-weight ratio, makes them ideal for partial dentures where the prosthesis needs to be lightweight. The Co-Cr alloy is more flexible than the Ni-Cr alloy, making it stronger and more durable. This makes them an ideal choice for dental prostheses that need to withstand high stresses and loads. [ABSTRACT FROM AUTHOR]

High-purity tellurium is a supporting material for contemporary high-tech industries. Zone refining is commonly used as a reliable final purification step to achieve higher purity levels of tellurium. However, the removal of Selenium (Se)—the most troublesome impurity in tellurium often occurring in quite high amounts—stays as the challenge during zone refining, due to its very unfavorable distribution coefficient. In addition, there is an important factor, essential to predict the zone refining efficiency (required number of passes), which is still seldom explored. Therefore, in the present work, the effect of different number of passes on the purification effect of tellurium was investigated by using 4N tellurium as raw material. Firstly, the possibility of removing vaporized Se through introducing an reductive gas flux was studied by testing initial concentrations of Se (13 ppm) and undergoing different process parameters. The experimental results showed that when the number of passes was 3, the impurity removal rate was low and the purification effect was poor; when the number of zone refining reached 9, the removal rate of most impurities in tellurium reached 100 pct, the removal rate of impurity Se reached 80.15 pct, and the total removal rate reached 89.49 pct, and the purity of tellurium ingot was 5N7. [ABSTRACT FROM AUTHOR]

We scaled up a previously developed method, known as Hot-top Pulsed Magneto-Oscillation (HPMO), to minimize crack, shrinkage-cavity, and macrosegregation in large ingots. Simulations on electromagnetic field, flow field, and temperature field revealed that an HPMO-induced electromagnetic field forces circulation of liquid steel near the riser, which causes grain nuclei and free grains to fall off the riser walls, drift away, and settle onto the middle of the mold. This phenomenon, known as "grain showering", refines solidified structure and reduces segregation. Joule heating generated by the HPMO process leads to mass feeding of the riser, which eliminates the development of pipes or central porosity and cracks. Based on simulation results, we designed a prototype HPMO apparatus and tested it on the production of ingots weighing 18 tonnes. Experimental results indicated that the use of HPMO grain showering did indeed yield expected solidified structure in ingots with a 56–83 pct reduction in equiaxed grain size, a 41 pct reduction in the number of inclusions, and a 50–75 pct reduction in normal carbon segregation comparing with that in controlled ingots. Furthermore, by using HPMO, shrinkage-induced pipes and center cracks that often occurred in the control ingots were eliminated, resulting in a fourfold increase in ductility in critical regions of the ingot. This work demonstrated the value of computation-aided simulation for improving manufacturing methods for the casting of large ingots. [ABSTRACT FROM AUTHOR]

A transient two-dimensional axisymmetric model is developed to investigate the influence of the applied transverse static magnetic field (TSMF) on the grain morphology of the electroslag remelted (ESR) ingot. The cellular automata-finite element (CAFE) technique is employed to elucidate the nucleation and growth of the grains. Moreover, an equivalent treatment method by adjusting the effective thermal conductivity is introduced to model the effect of the electromagnetic vibration (EMV) generated by the applied 0.05T TSMF on the temperature distribution. The close correspondence between the experimental data and the simulation outcomes demonstrates the validity and reliability of the computational model. The results show that with the effective thermal conductivity increasing from η to 3 η , the proportion of equiaxed grain increases from 25.1 to 48.7 pct and the grains get refined. Furthermore, the increase in effective thermal conductivity correlates with a decrease in both the local solidification time (LST) and the second dendrite arm spacing (SDAS) at the central region, suggesting a finer microstructure of the ingot. In addition, as the effective thermal conductivity increases, a substantial decrease in the maximum depth of the metal pool is observed, reducing from 53.9 to 19.4 mm, which should be conductive to microstructure refinement and macrosegregation alleviation. [ABSTRACT FROM AUTHOR]

Inclusions in metallurgical grade silicon (MG-Si) can significantly degrade the quality and performance of silicon materials. Thus, it is essential to implement effective measures to control and minimize their presence. This study investigates the morphology, distribution, and microstructural evolution of inclusions in silicon by introducing varying amounts of Sn. The changes in Fe content at different positions in silicon ingots before and after Sn refining were examined. The study demonstrates that Sn refining can reduce the number of inclusions at the bottom of silicon ingots by up to 71.3 pct. The morphology of inclusions undergoes a transition from fine filaments and sporadic dots to block-like formations, ordered short rods, and dots. There is an upward migration of Fe in the vertical direction, leading to a reduction in Fe content at the bottom from 0.61 to 0.25 pct, representing a significant decrease of 59.03 pct. These findings suggest that the addition of Sn to silicon can effectively remove Fe impurities. Additionally, the incorporation of Sn refining enables a reduction in the formation of the Si7Al8Fe5 phase and enhances the selectivity of the organosilicon monomer synthesis process. Remarkably, the partial substitution of Ti by Al leads to the formation of the FeSi2Ti(Al) phase. However, Ca tends to concentrate in Sn and remains unaffected by the Sn content. These empirical findings offer experimental evidence for effectively reducing and controlling the quantity and morphology of inclusions in MG-Si, thereby significantly enhancing the quality of MG-Si production. [ABSTRACT FROM AUTHOR]

The production of homogeneous Ti–10Nb–(1–3)Mo (at %) alloys in the form of semifinished products (plates) was studied through multiple remeltings and homogenization annealing. Metallographic studies of the resulting materials in cast, rolled, and annealed states were carried out. The effect of annealing and composition on the structure, phase composition, and mechanical properties of the Ti–10Nb–(1–3)Mo alloy was revealed. Homogeneity after smelting was achieved by annealing at a temperature of 950°C for 12 h. An increase in the Mo content in the Ti–10Nb–(1–3)Mo alloy led to an increase in the strength of the alloys, while the ductility decreased. The achievement of high strength characteristics in selected alloys was associated with the development of annealing parameters after plastic deformation, namely, controlling the size of recrystallized grains and separating the α and β phases. In addition to α-Ti and β-Ti, the samples contained small amounts of ω-Ti, which led to a sharp increase in the hardness of the samples. [ABSTRACT FROM AUTHOR]

A technique for simplified simulation of the forging of large ingots using modern machine-learning methods for constructing models that describe stages of thermomechanical processing is described. [ABSTRACT FROM AUTHOR]

The behavior of the steel structure of cast ingot during rolling at the radial rolling mill RSP-10/30 was studied. The ingots for rolling were produced by vacuum induction melting from stainless steel 12H13. The ingots were rolled from a single heating in several passes from a diameter of 32 to 26 mm at 1200 °C and from 25 to 13 mm at 800 °C. This enabled, per one operation, to substantially change the sample structure from a coarse-grained cast dendritic structure of 0.5–1.5 mm to an equiaxed fine-grained structure with grain size 1–4 μm in the peripheral part and elongated grains of larger size in the axial part of the rolled billet. [ABSTRACT FROM AUTHOR]

The ProCAST software package was used to simulate the crystallization of a slab ingot on an installation for semi-continuous casting of aluminum alloys, which made it possible to determine the distribution of temperature, solid phase volume and melt flow velocities during the crystallization of slab ingots with a cross section of 200 × 60 mm at various casting parameters. Verification of the model was carried out on a physical model of the installation, which represents a model of an industrial casting unit for semi-continuous casting. 1580 aluminum-magnesium alloy was used as a simulation object. In the ingot obtained by physical simulation carried out according to computer simulation modes, no surface or internal defects were detected, and the hydrogen concentration in it was 0.17 cm3/100 g, which meets the requirements of regulatory documents. [ABSTRACT FROM AUTHOR]

The results of experimental studies of the process of electroslag remelting of titanium in a chamber furnace at different values of pressure in the melting space, from vacuum to excess pressure, are given. Experiments were carried out during the melting of ingots with a diameter of 85 and 105 mm from titanium alloys VT1-0 and VT22 using fluoride-chloride flux AN-T4. The pressure of the inert gas in the furnace chamber was varied from 20 to 300 kPa. It is shown that in the entire studied range of pressures, the electroslag process proceeded stably with the formation of ingots with a high-quality side surface and a dense structure, without pores, slag inclusions and other internal defects. Experimental data on the effect of pressure in the melting space on the gas composition and structure of titanium ingots are given. the possibility of reducing the hydrogen content in titanium alloys by carrying out the electroslag process in vacuum conditions is shown. It was also established that the VT1-0 titanium ingot, melted under vacuum conditions, is characterized by a larger grain size compared to the ingot obtained under excess pressure. [ABSTRACT FROM AUTHOR]