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For the first time, the experimental processing condition of a rotating directional solidification is simulated in this work, by means of a grand-potential-based phase-field model. To simulate the rotating directional solidification, a new simulation setup with a rotating temperature field is introduced. The newly developed configuration can be beneficent for a more precise study of the ongoing adjustment mechanisms during temperature gradient controlled solidification processes. Ad hoc, the solidification of the ternary eutectic system Bi-In-Sn with three distinct solid phases α,β,δ is studied in this paper. For this system, accurate in situ observations of both directional and rotating directional solidification experiments exist, which makes the system favorable for the investigation. The two-dimensional simulation studies are performed for both solidification processes, considering the reported 2D patterns in the steady state growth of the bulk samples. The desired αβαδ phase ordering repeat unit is obtained within both simulation types. By considering anisotropy of the interfacial energies, experimentally reported tilted lamellae with respect to normal vectors of the solidification front, as well as predominant role of αβ anisotropy in tilting phenomenon, are observed. The results are validated by using the Jackson–Hunt analysis and by comparing with the existing experimental data. The convincing agreements indicate the applicability of the introduced method.

The multi-crystalline silicon (mc-Si) ingot quality is mainly influenced by the generation of impurities and their diffusion. A transient global simulation helps to study the impurities distribution in the grown mc-Si ingot. In this work, crucible materials such as quartz and carbon are used to grow mc-Si ingots, and the impurities distribution of both silicon ingots are analyzed. Non-metallic impurities such as oxygen, and carbon are the major impurities formed in the silicon crystal during the directional solidification (DS) process. These impurities arise from the parts of the furnace and are segregated partly into the mc-Si ingot. The impurities such as oxygen and carbon were analyzed at the melt-crystal interface as well as in grown mc-Si ingots. Further, the gaseous impurities such as silicon monoxide and carbon monoxide are analyzed in the melt-free surface. The solar cell performance mainly depends on the quality of the silicon ingot. The mc-Si ingot grown by silicon nitride-coated carbon crucible gives better quality for photovoltaic industries.

The solidification processes of two compositions, hypereutectic (21.0 mol% Y2O3–79.0 mol% Al2O3) and eutectic (18.5 mol% Y2O3–81.5 mol% Al2O3), were used via the horizontal directional solidification (HDS) method to produce two ingots with dimensions of 317 × 220 × 35 mm and 210 × 180 × 35 mm, respectively. The first ingot was heterogeneous and characterized by a two-layer structure with an expressed horizontal boundary, which is parallel to the solidification direction (an experimental fact observed for the first time), separating eutectic-type ceramics in the upper layer from the lower one containing the YAG dendrites. Considering the heat transfer feature characteristic of the HDS method and its action during the solidification of materials scattering thermal radiation, an explanation of the occurrence of such structure has been proposed. On this basis, the solidification parameters of the second ingot, providing its homogeneous structure, were selected. Characterization of the crystallographic texture and microstructure of both ingots revealed the advantage of the second solidification processing conditions.

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.

The trends in the development of a technology for the production of the hot gas path parts of a gas turbine engine (GTE) by directional solidification from superalloys are considered. The existing special-purpose equipment used in Russia, the United States, Germany and other countries to produce blades with a directional and single-crystal structure is analyzed. The prospects of directional solidification with a liquid metal cooler in the production of GTE blades for both modern and promising GTEs are clearly demonstrated.

The electromagnetic directional solidification (DS) phase separation experiments of high silicon 90 wt.% Si–Ti alloy were performed under various pulling-down speeds. The results showed that Si enriched layer, Si + TiSi 2 -rich layer and Si–Ti–Fe alloy layer appeared successively in axial direction of ingot after electromagnetic DS of 90 wt.% Si–Ti alloy melt at different pulling-down speeds. Separation of primary Si and segregation mechanism of metal impurities (Fe) during the electromagnetic DS process were controlled by pulling-down speed of ingot and electromagnetic stirring. When pulling-down speed was 5 μm/s, minimum thickness of the Si enriched layer was 29.4 mm, and the highest content of primary Si in this layer was 92.46 wt.%; meanwhile, the highest removal rate of Fe as metal impurity was 92.90%. The type of inclusions in the Si enriched layer is determined by Fe content of segregated Si enriched layer. When the pulling-down speed was 5 μm/s, the inclusions in the Si enriched layer were TiSi 2 . Finally, when the pulling-down speed reached greater than 5 μm/s, the inclusions in the Si enriched layer evolved into TiSi 2  + τ 5 .

Numerical simulation has been carried out on the directional solidification (DS) for the growth of multi-crystalline silicon (mc-Si) ingot through a 2-dimensional axis-symmetric global transient model. In this work, we used a silicon nitride-coated carbon crucible DS system. Due to this, the thermal conductivity and density of the crucible are changed which may affect the furnace's thermal field. Changes in the thermal field can impact the temperature distribution, von Mises stress, maximum shear stress, normal stresses, average growth rate, and power consumption. Using numerical simulation based on the finite volume method the solidification process is analyzed and investigated with a silicon nitride-coated carbon crucible (modified system) and silicon nitride-coated quartz crucible (conventional system). Solar cell performance depends directly on the quality of the mc-Si ingot. The modified grown ingot is more favorable for PV applications.

This study investigated an efficient method to reach a high yield of purified silicon crystals using solvent refining with directional solidification process(by applying a pulling out speed of 100μm/s). The main point is to add Sn in Al-Si melts during a 3kHz alternating electromagnetic field. The results show that the purified Si crystals can grow much bigger with Sn addition. When samples dealt in resistance with the Sn additions as 0, 10, 20, 30wt.%, the mean widths of Si crystals are 121.80, 303.45, 265.61, 244.19μm, respectively. While dealt in alternating electromagnetic furnace, the mean widths of the Si crystals are 144.75, 196.34, 250.86, 203.87μm, respectively. The XRD patterns show that no complex compounds formed in the systems, which means that the purified Si won’t be contaminated by impurities. Moreover, when Sn addition is 30wt.%, with 100 μm/s, after alternating electromagnetic directional solidification (AEM-DS), the Si content of Si-rich area can reach 90.49wt.%, which is higher about 20wt.% than the sample without Sn addition. The pulling out speed used in our research is 100μm/s, which is much higher than the traditional pulling out speed (10μm/s order of magnitudes, reported in other works). This method can potentially reach energy saving and high yield to manufacture purified silicon.

Size upgrading is the main method to increase production capacity and reduce production costs during the directional solidification of silicon ingots. The distributions of oxygen and carbon impurities in G6 and G7 directional solidification furnaces are studied. The simulation results show that the distributions of oxygen and carbon impurities change significantly in the silicon ingot at different growth stages, especially the position of the highest concentration of carbon impurities has shifted. Compared with the G6 furnace, the average concentrations of oxygen and carbon in silicon crystal in the G7 furnace are reduced by 6.7%, and 7.3% respectively. With the growth of silicon crystal, the average concentration of oxygen gradually decreases, while the average concentration of carbon gradually increases.

High Cr white irons with various fractions of primary dendrite have been prepared through the modification of their chemical composition. Increasing C and Cr contents decreased the primary dendrite fraction. Eutectic solidification occurred with the phase fraction ratio of austenite: M7C3 = 2.76:1. The measured primary dendrite fractions were similar to the calculated results. ThermoCalc calculation successfully predicted fractions of M7C3, austenite, and M23C6. Conventional heat treatment at high temperature caused a destabilization of austenite, releasing it’s solute elements to form M23C6 carbide. Precipitation of M23C6 during destabilization preferentially occurred within primary (austenite) dendrite, however, the precipitation scarcely occurred within austenite in eutectic phase. Thus, M23C6 precipitation by destabilization was relatively easy in alloys with a high fraction of primary dendrite.