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Advances in Alloys - Microstructure, Manufacturing and Analysis

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Metals and Alloys".

Deadline for manuscript submissions: closed (20 February 2023) | Viewed by 16646

Special Issue Editors


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Guest Editor
Faculty of Foundry Engineering, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow, Poland.
Interests: solidification modelling; microstructure; cellular automaton; thermal analysis; gas–eutecic porous materials
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Guest Editor
Faculty of Foundry Engineering, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Kraków, Poland
Interests: cellular automaton; solidification modelling; nodular cast iron; alloys; temperature-controlled growth; diffusion controlled transformation

Special Issue Information

Dear Colleagues,

Metal alloys are the most commonly used construction materials in the world. The metallic materials process chain begins with extractive metallurgy processes. The materials obtained from ores are used as raw materials for the alloy melting of a given chemical composition. These alloys are then, after possible ladle metallurgy processes, cast into ingots intended for metal forming processes or into castings not subjected to further plastic deformation. The functional properties of both castings and products after metal forming can be significantly improved by heat or thermochemical treatment. Each of these manufacturing steps can affect the microstructure, properties and quality of the finished products. This also applies to products made from metals by powder sintering treatment, additive manufacturing methods or welding.

The purpose of the papers of the Special Issue (SI) is to present the results of a study of the effects of different chain links on the microstructure and functional properties of alloys. The purpose of the publications that will be collected in it is not only to present advances in alloy manufacturing and research in the development of their technologies. We also want to present the impact of metallurgical and foundry technologies on microstructure and performance properties. This SI welcomes articles on advances in the development of technologies for manufacturing cast and metal formed products from steel, cast iron, special alloys, and nonferrous metals or cast composite materials.

The topics of the submitted articles may range from the development of new alloy grades to the presentation of advances in the workflows of their processing, in the field of methods of microstructure and property analysis. How do modern technological processes affect the macro- and microstructures of alloy? What effect does the resulting structure have on product properties? How do multi-scale and multi-physics modeling techniques support the development and optimization of manufacturing processes? Can the microstructure of finished products be affected by extractive metallurgy processes or secondary product recycling technology?

Prof. Dr. Andriy Burbelko
Dr. Daniel Gurgul
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • advances in technology
  • chain: “technology - structure – properties”
  • simulation of microstructure formation
  • microstructure and property analysis

Published Papers (11 papers)

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Research

10 pages, 3495 KiB  
Article
Isobaric Thermal Expansivity and Isothermal Compressibility of Liquid Metals
by Yuri N. Starodubtsev and Vladimir S. Tsepelev
Materials 2023, 16(10), 3801; https://doi.org/10.3390/ma16103801 - 17 May 2023
Cited by 1 | Viewed by 981
Abstract
The relationship between the volumetric thermodynamic coefficients of liquid metals at the melting point and interatomic bond energy was studied. Using dimensional analysis, we obtained equations that connect cohesive energy with thermodynamic coefficients. The relationships were confirmed by experimental data for alkali, alkaline [...] Read more.
The relationship between the volumetric thermodynamic coefficients of liquid metals at the melting point and interatomic bond energy was studied. Using dimensional analysis, we obtained equations that connect cohesive energy with thermodynamic coefficients. The relationships were confirmed by experimental data for alkali, alkaline earth, rare earth, and transition metals. Cohesive energy is proportional to the square root of the ratio of melting point Tm divided by thermal expansivity αp. Thermal expansivity does not depend on the atomic size and atomic vibration amplitude. Bulk compressibility βT and internal pressure pi are related to the atomic vibration amplitude by an exponential dependence. Thermal pressure pth decreases with an increasing atomic size. Fcc and hcp metals with high packing density, as well as alkali metals, have the relationships with the highest coefficient of determination. The contribution of electrons and atomic vibrations to the Grüneisen parameter can be calculated for liquid metals at their melting point. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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15 pages, 7298 KiB  
Article
Evaluation of the Number of Primary Grains in Hypoeutectic Chromium Cast Iron with Different Wall Thickness Using the ProCAST Program
by Edward Guzik, Dariusz Kopyciński, Andriy Burbelko and Andrzej Szczęsny
Materials 2023, 16(8), 3217; https://doi.org/10.3390/ma16083217 - 19 Apr 2023
Cited by 3 | Viewed by 1058
Abstract
The treatment of inoculation of white cast iron with carbide precipitations that consist of increasing the number of primary austenite grains is not as well-known as the treatment of inoculation of gray cast iron in which the number of eutectic grains increases. In [...] Read more.
The treatment of inoculation of white cast iron with carbide precipitations that consist of increasing the number of primary austenite grains is not as well-known as the treatment of inoculation of gray cast iron in which the number of eutectic grains increases. In the studies included in the publication, experiments were carried out using the addition of ferrotitanium as an inoculant for chromium cast iron. The Cellular Automaton Finite Elements (CAFE) module of ProCAST software was used in order to analyze the formation of the primary structure of hypoeutectic chromium cast iron in a casting of various thicknesses. The modeling results were verified using Electron Back-Scattered Diffraction (EBSD) imaging. The obtained results confirmed obtaining a variable number of primary austenite grains in the cross-section of the tested casting, which significantly affects the strength properties of the obtained chrome cast iron casting. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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14 pages, 3665 KiB  
Article
Changes in Abrasion Resistance of Cast Cr-Ni Steel as a Result of the Formation of Niobium Carbides in Alloy Matrix
by Grzegorz Tęcza
Materials 2023, 16(4), 1726; https://doi.org/10.3390/ma16041726 - 19 Feb 2023
Cited by 2 | Viewed by 1487
Abstract
Cast austenitic chromium-nickel steel is commonly used for the manufacture of machine parts and components, which are exposed to the attack of corrosive media and abrasive wear during operation. The most commonly used grades include GX2CrNi18-9 and X10CrNi18-8 as well as GX2CrNiMo17-12-2 and [...] Read more.
Cast austenitic chromium-nickel steel is commonly used for the manufacture of machine parts and components, which are exposed to the attack of corrosive media and abrasive wear during operation. The most commonly used grades include GX2CrNi18-9 and X10CrNi18-8 as well as GX2CrNiMo17-12-2 and X6CrNiMoNb17-12-2. To improve the abrasion resistance of cast chromium-nickel steel, primary niobium carbides were produced in the metallurgical process by increasing the carbon content and adding Fe-Nb. The microstructure of the obtained test castings consisted of an austenitic matrix and primary niobium carbides evenly distributed in this matrix. The measured hardness of the samples after heat treatment ranged from 215 to 240 HV and was higher by about 60 units than the hardness of the reference cast GX10CrNi18-9 steel, which had a hardness of about 180 HV. Compared to the reference cast steel, the abrasive wear resistance of the tested cast chromium-nickel steel (measured in Miller test) with contents of 4.4 and 5.4 wt% Nb increased only slightly, i.e., by 5% for the lower niobium content and 11% for the higher niobium content. Compared to ordinary cast GX10CrNi18-9 steel, the addition of 9.2 wt% Nb reduced the abrasive wear by almost 2.5 times. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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17 pages, 9250 KiB  
Article
Effect of Isothermal Holding at 750 °C and 900 °C on Microstructure and Properties of Cast Duplex Stainless Steel Containing 24% Cr-5% Ni-2.5% Mo-2.5% Cu
by Barbara Elżbieta Kalandyk, Renata Elżbieta Zapała and Paweł Pałka
Materials 2022, 15(23), 8569; https://doi.org/10.3390/ma15238569 - 01 Dec 2022
Cited by 3 | Viewed by 1168
Abstract
Changes in the microstructure and selected mechanical properties of two-phase ferritic-austenitic cast steel containing 24% Cr-5% Ni-2.5% Mo-2.5% Cu after isothermal holding at 750 °C and 900 °C are presented. The choice of the two temperatures of isothermal holding was dictated by the [...] Read more.
Changes in the microstructure and selected mechanical properties of two-phase ferritic-austenitic cast steel containing 24% Cr-5% Ni-2.5% Mo-2.5% Cu after isothermal holding at 750 °C and 900 °C are presented. The choice of the two temperatures of isothermal holding was dictated by the precipitation of brittle phases within a range of 600 °C–950 °C, while the holding time depended on the casting cooling time in the mould. Changes in the microstructure were studied by the SEM-EDS and XRD techniques. As a result of the decomposition of the eutectoid ferrite, a σ phase that was rich in Cr, Mo, and Ni and a secondary γ2 austenite with Widmannstätten morphology were formed. Compared to the austenite, the chemical composition of the secondary γ2 austenite showed depletion of Cr and Mo. In the ferrite, the presence of Cr2N nitrides was also detected. After a holding time of 3 h at 900 °C, these phases increased the hardness of the tested cast steel to approximately 275 HV10. At the same time, the UTS value was recorded to decrease with the increasing temperature based on the tensile test results. At 750 °C, the value of UTS was 250 MPa for 1 h of holding and 345 MPa for 3 h of holding. These values decreased after increasing the temperature to 900 °C and amounted to 139 for 1 h holding and 127 MPa for 3 h holding. It was also found that the elongation values at 750 °C ranged from 7–10%, while they amounted to 35–37% at 900 °C. A fracture analysis of the tested cast steel showed that in the prevailing part, the fractures were made of ductile nature with an arrangement of dimples that is typical for this type of fracture. Non-metallic inclusions that are typical for cast steel (i.e., oxides and nitrides) were also found in the area of the fractures. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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10 pages, 2802 KiB  
Article
Effects of Cerium Doping on the Mechanical Properties and Energy-Releasing Behavior of High-Entropy Alloys
by Yusong Ma, Liang Zhou, Kaichuang Zhang, Xiqiang Gai, Jinyan He and Xinggao Zhang
Materials 2022, 15(20), 7332; https://doi.org/10.3390/ma15207332 - 20 Oct 2022
Cited by 2 | Viewed by 1175
Abstract
Energetic structural materials play an important role in improving the damage performance of future weapons. To improve the energy-releasing behavior, Al0.5NbZrTi1.5Ta0.8Cex high-entropy alloys were prepared by vacuum-arc melting. The results showed the presence of BCC and [...] Read more.
Energetic structural materials play an important role in improving the damage performance of future weapons. To improve the energy-releasing behavior, Al0.5NbZrTi1.5Ta0.8Cex high-entropy alloys were prepared by vacuum-arc melting. The results showed the presence of BCC and FCC phases in the alloy with dendritic-morphology-element segregation and there were significant dislocations in the alloys. The current study focused on the effects of cerium content on the dynamic compressive mechanical and energetic characteristics. Cerium doping enhanced the energy-releasing characteristics of high-entropy alloys. The severity of the reaction increased with the increase in the cerium content, while the dynamic compressive strength generally decreased with the increase in cerium content. The Al0.5NbZrTi1.5Ta0.8Ce0.25 showed excellent mechanical and energy-releasing characteristics. The ballistic experiments indicated that Al0.5NbZrTi1.5Ta0.8Ce0.25 can penetrate 6-millimeter A3 plates and ignite the cotton behind the target at a velocity of 729 m/s, making it an ideal energetic structural material. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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12 pages, 5284 KiB  
Article
Effect of Slurry Thickness on the Quality of Aluminized Coatings
by Zhuoyue Li, Cheng Wang, Xiangyu Ding, Xin Li, Jiabo Yu, Qiuliang Li and Yi Qu
Materials 2022, 15(19), 6758; https://doi.org/10.3390/ma15196758 - 29 Sep 2022
Cited by 1 | Viewed by 1872
Abstract
Diffusion aluminum coating is crucial to protect aero-engine turbine blades from high-temperature oxidation. Slurry aluminizing, as a commonly-used coating preparation technology, has variations in the process parameters that directly affect the quality of the coating. Therefore, this paper investigates the effect of slurry [...] Read more.
Diffusion aluminum coating is crucial to protect aero-engine turbine blades from high-temperature oxidation. Slurry aluminizing, as a commonly-used coating preparation technology, has variations in the process parameters that directly affect the quality of the coating. Therefore, this paper investigates the effect of slurry thickness on coating quality. Different forms of aluminized coatings were obtained by coating nine DZ22B nickel-based superalloy plates of the same size with different slurry thicknesses while keeping other parameters constant. These aluminized coatings were characterized using a scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS), an X-ray diffractometer (XRD), and a surface gauge. The results show that the AlNi phase dominates the matrix of the aluminized coating, and the outer layer of the coating has white dotted precipitates of Cr. As the slurry thickness increases, the coating thickness increases, and the proportion of the outer layer in the overall coating increases. In contrast, the thickness of the interdiffusion layer does not change significantly. The thicker the slurry, the higher the Al content of the coating surface. A medium-thickness slurry can form a smooth aluminizing coating with a roughness Ra < 4.5 μm surface. The combined results show that a medium-thick slurry can produce a high-quality coating. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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14 pages, 6990 KiB  
Article
Effect of Inoculation Treatment on Number of Primary Austenite Grains in Hypoeutectic Chromium Cast Iron: EBSD Imaging and Mathematical Structure Prediction
by Dorota Siekaniec, Dariusz Kopyciński, Edward Guzik and Andrzej Szczęsny
Materials 2022, 15(18), 6318; https://doi.org/10.3390/ma15186318 - 12 Sep 2022
Cited by 2 | Viewed by 1470
Abstract
This study proved the influence of an inoculation substance on the primary structure of chromium-cast iron. The inoculation procedure has developed very well in the field of grey cast iron production and mainly concerns the crystallisation of graphite eutectic grains in this material. [...] Read more.
This study proved the influence of an inoculation substance on the primary structure of chromium-cast iron. The inoculation procedure has developed very well in the field of grey cast iron production and mainly concerns the crystallisation of graphite eutectic grains in this material. However, in chromium cast iron, the inoculation problem is not well-recognised due to the formation of chromium carbides in white cast iron. One can easily increase the number of carbides in the cast iron’s structure, but this procedure will not always bring the expected benefits in terms of increasing the overall mechanical properties. In the research included in this publication, an experiment was carried out with the use of ferrotitanium as an inoculant for chromium-cast iron. As a result of using the EBSD (electron backscatter diffraction analysis) imaging method, it was proven that the Fe–Ti interaction significantly influenced the primary structure of chromium cast iron that was formed by austenite grains. The paper presents the growth laws of primary austenite grains in modified hypoeutectic chromium cast iron depending on the degree of supercooling, ΔT, and the amount of the Fe–Ti inoculant M. The results of the research made it possible to predict the structure of hypoeutectic chromium cast iron after Fe–Ti inoculation treatment. The article proves that the use of the inoculant can change the primary structure of chromium cast iron, increasing its impact strength by more than three times. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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20 pages, 8754 KiB  
Article
Procedure of Eliminating Porosity in Grey Cast Iron with Low Sulphur Content
by Józef Dorula, Dariusz Kopyciński, Edward Guzik and Andrzej Szczęsny
Materials 2022, 15(18), 6273; https://doi.org/10.3390/ma15186273 - 09 Sep 2022
Viewed by 1464
Abstract
This study shows that the inoculation process of a molten alloy is crucial in disposing of porosity-type defects. A thermal analysis is used to assess the physico-chemical state of a molten alloy, which can be an indicator of the inoculation effect. A modern [...] Read more.
This study shows that the inoculation process of a molten alloy is crucial in disposing of porosity-type defects. A thermal analysis is used to assess the physico-chemical state of a molten alloy, which can be an indicator of the inoculation effect. A modern thermal analysis should be able to perform a quick data-analysis and provide information about any possible problems in a casting if it is poured with the analysed alloy. The time of the transmission of this information depends on whether we can make a decision and introduce changes to the metallurgical process. An important piece of information that can be obtained in this way is a message about the possibility of the appearance of porosity in a cast iron casting. In such a situation, an operator can react by applying an additional dose of inoculant. The porosity that is indicated by the thermal analysis systems can be either gaseous or shrinkage in nature. The research that is presented in this paper is based on two industrial castings that are made of cast iron with reduced sulphur content, in which shrinkage porosity occurred and was detected during the mechanical machining of the castings. As a result of laboratory tests in which iron powder was introduced along with an inoculant, a mixture was developed that, when applied under industrial conditions, eliminated the porosity defects by increasing the number of austenite dendrites. The ITACA thermal analysis system was used at each stage of the research, which allowed for the faster and more precise determination of the appropriate amount of the inoculant mixture that was used. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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19 pages, 9275 KiB  
Article
Optimisation of Solidification Structure and Properties of Hypoeutectic Chromium Cast Iron
by Dorota Siekaniec, Dariusz Kopyciński, Edward Tyrała, Edward Guzik and Andrzej Szczęsny
Materials 2022, 15(18), 6243; https://doi.org/10.3390/ma15186243 - 08 Sep 2022
Cited by 6 | Viewed by 1515
Abstract
This paper presents a comprehensive approach to optimising the structure and properties of chromium cast iron that is intended for use in the production of castings that operate under abrasive-wear conditions. In the study, chromium cast iron was inoculated to reduce the grain [...] Read more.
This paper presents a comprehensive approach to optimising the structure and properties of chromium cast iron that is intended for use in the production of castings that operate under abrasive-wear conditions. In the study, chromium cast iron was inoculated to reduce the grain size in the solidification structure. The finer-grained structure of the casting has a positive effect on its mechanical properties. A number of inoculants have been used that allow the elimination of many types of casting defects: hot cracks and porosities that often occur during the production of chromium cast iron castings. Another advantage of the developed inoculation procedure is the resulting increase in the toughness of chromium cast iron. It should be emphasised that this cast iron does not have a high impact strength in its as-cast condition due to the formation of chromium carbides in the structure. This work also proposes a specially designed heat treatment for inoculated cast iron. The parameters of the applied heat treatment were determined on the basis of dilatometric tests. The visible deviation on a dilatogram at a temperature of about 600 °C is the result of a partial martensitic transformation in the area of grain boundaries. Therefore, the increase in abrasion resistance chromium cast iron is mainly due to the appearance of martensite. The microstructure of the investigated cast iron is particularly desirable in the case of alloys that work with lubrication. The microcavities that are formed by the abrasion of the softer phase constitute natural grease, which reduces abrasive wear. Under the influence of heat treatment, only a part of austenite located near the carbides is destabilized and transformed into martensite. Therefore, this phase of composition formation provided much greater resistance to abrasive wear and hardness. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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16 pages, 9849 KiB  
Article
Influence of High-Pressure Die Casting Parameters on the Cooling Rate and the Structure of EN-AC 46000 Alloy
by Wojciech Kowalczyk, Rafał Dańko, Marcin Górny, Magdalena Kawalec and Andriy Burbelko
Materials 2022, 15(16), 5702; https://doi.org/10.3390/ma15165702 - 18 Aug 2022
Cited by 9 | Viewed by 1940
Abstract
The paper presents the results of the research on the impact of process parameters of high-pressure, cold-chamber die casting of an industrial casting made of aluminium alloy on the casting properties assessed macroscopically by measuring the casting average density and microscopically through the [...] Read more.
The paper presents the results of the research on the impact of process parameters of high-pressure, cold-chamber die casting of an industrial casting made of aluminium alloy on the casting properties assessed macroscopically by measuring the casting average density and microscopically through the characteristics of the casting microstructure. The analysis covers the influence of three selected velocity settings of the pressing plunger, which determine the filling time, and three values of the compression pressure setting characteristic of the third phase of the casting process. The cooling and solidification simulations of the casting were performed using the ProCAST software. During the simulation tests, the impact of the filling rate of the alloy into the die cavity on the cooling rate and the alloy solidification path at selected points were determined. The conducted research allowed linking the process parameters with the parameters of the casting structure with different wall thicknesses. Metallographic examinations of the castings were carried out using a light microscopy, SEM, and EDS analysis. The fraction of the phases α(Al), the size of dendritic cells, and the size of silicon particles, in the cross-sections of the castings with wall thickness of 3, 6, and 11 mm, respectively, were determined. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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21 pages, 9951 KiB  
Article
Shape-Dependent Strength of Al Si9Cu3FeZn Die-Cast Alloy in Impact Zone of Conformal Cooling Core
by Jarosław Piekło, Andriy Burbelko and Aldona Garbacz-Klempka
Materials 2022, 15(15), 5133; https://doi.org/10.3390/ma15155133 - 24 Jul 2022
Cited by 5 | Viewed by 1516
Abstract
This article presents the results of shape-dependent strength analyses in die-castings from traditional (straight-drilled) and conformal core-cooling moulds. Cores with a traditional cooling layout were made of H13 steel using machining, and the working sections of the conformal cores were made using the [...] Read more.
This article presents the results of shape-dependent strength analyses in die-castings from traditional (straight-drilled) and conformal core-cooling moulds. Cores with a traditional cooling layout were made of H13 steel using machining, and the working sections of the conformal cores were made using the selective laser melting method (SLM). Two series of casts were produced in the same mould. For Series A, the mould was fitted with traditional cooling cores, and for Series B, the same mould was fitted with conformal ones. The cast specimens were subjected to two weeks of natural ageing. The strength testing of the casts determined the levels of the destructive forces. The destructive forces in the core-cooling impact zones were approximately 28% higher in the B samples than they were in the A samples. The impact of the alloy’s porosity, density, and microstructure on the strengths of the casts was demonstrated. The alloy densities in the central (broken-off) fragments of the casts from Series A were 2.6646 g/cm3; these were 2.6791 g/cm3 in the cases of casts from Series B. The values of the secondary dendrite arm space (SDAS) ranged from 6 to 13 μm in the analysed cross-section of the set of the A casts, and between 3 and 12 μm in the same zone of the set of the B casts. The results of the experimental determinations of the casts porosity levels and SDAS parameters were compared with the results of numerical simulations that were carried out in ProCAST software. Full article
(This article belongs to the Special Issue Advances in Alloys - Microstructure, Manufacturing and Analysis)
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