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Advances in Materials Processing (Second Volume)

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Manufacturing Processes and Systems".

Deadline for manuscript submissions: closed (20 July 2023) | Viewed by 36785

Special Issue Editor

Department of Material System Engineering, Pukyong National University, Busan 48513, Republic of Korea
Interests: nanomaterials; dissimilar materials; powder metallurgy; composite materials processing; functionally graded materials; surface modification; nanoparticles
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Since industrial development began, materials processing is central to the field of materials science and engineering, and is a vital step in manufacturing. Materials processing is an important process for realizing the structural features (e.g., crystal structure, microstructure, size, and shape) required for the product to perform well in the intended application by properly utilizing and designing the composition of a given material. It involves a complex series of chemical, thermal, and physical processes that prepare a starting material, create a shape, retain that shape, and refine the structure and shape. The conversion of the starting material to the final product occurs in three steps: preparation of the starting material, processing operation, and post-processing operation(s). Recently, trends in the high-tech industry are pushing toward miniaturization, the creation of products with complex shapes, and multi-functional materials. To keep up with ever-increasing demands, materials processing has been continuously advancing in terms of production, efficiency and performance qualification.

The main aim of the Special Issue is to discuss the topics of processing, manufacturing, structure/property relationship and applications in advanced materials. All of the single phase and alloy, and composite materials in metals, ceramics, and polymers are of interest.

It is our pleasure to invite you to submit a manuscript for this Special Issue.

Prof. Dr. Hansang Kwon
Guest Editor

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Keywords

  • processing
  • manufacturing
  • powder metallurgy
  • composite materials processing
  • surface modification
  • plasma synthesis
  • laser processing

Published Papers (24 papers)

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Research

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16 pages, 15797 KiB  
Article
Study on Rolling Defects of Al-Mg Alloys with High Mg Content in Normal Rolling and Cross-Rolling Processes
by Seong-Sik Lim, Je-Pyo Hong, Minki Kim, Young-Chul Park, Sang-Mock Lee, Dae-Yeon Cho and Chang-Hee Cho
Materials 2023, 16(18), 6260; https://doi.org/10.3390/ma16186260 - 18 Sep 2023
Viewed by 781
Abstract
This study investigated defect formation and strain distribution in high-Mg-content Al-Mg alloys during normal rolling and cross-rolling processes. The finite element analysis (FEA) revealed the presence of wave defects and strain localization-induced zipper cracks in normal cold rolling, which were confirmed by the [...] Read more.
This study investigated defect formation and strain distribution in high-Mg-content Al-Mg alloys during normal rolling and cross-rolling processes. The finite element analysis (FEA) revealed the presence of wave defects and strain localization-induced zipper cracks in normal cold rolling, which were confirmed by the experimental results. The concentration of shear strain played a significant role in crack formation and propagation. However, the influence of wave defects was minimal in the cross-rolling process, which exhibited a relatively uniform strain distribution. Nonetheless, strain concentration at the edge and center regions led to the formation of zipper cracks and edge cracks, with more pronounced propagation observed in the experiments compared to FEA predictions. Furthermore, texture evolution was found to be a crucial factor affecting crack propagation, particularly with the development of the Goss texture component, which was observed via electron backscattered diffraction analysis at bending points. The Goss texture hindered crack propagation, while the Brass texture allowed cracks to pass through. This phenomenon was consistent with both FEA and experimental observations. To mitigate edge crack formation and propagation, potential strategies involve promoting the formation of the Goss texture at the edge through alloy and process conditions, as well as implementing intermediate annealing to alleviate stress accumulation. These measures can enhance the overall quality and reliability of Al-Mg alloys during cross-rolling processes. In summary, understanding the mechanisms of defect formation and strain distribution in Al-Mg alloys during rolling processes is crucial for optimizing their mechanical properties. The findings of this study provide insights into the challenges associated with wave defects, strain localization, and crack propagation. Future research and optimization efforts should focus on implementing strategies to minimize defects and improve the overall quality of Al-Mg alloys in industrial applications. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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24 pages, 3984 KiB  
Article
Study of the Relationship between Entropy and Hardness in Laser Cutting of Hardox Steel
by Constantin Cristinel Girdu and Catalin Gheorghe
Materials 2023, 16(13), 4540; https://doi.org/10.3390/ma16134540 - 23 Jun 2023
Cited by 1 | Viewed by 1034
Abstract
The article presents the findings of a study on the machining of 10 mm thick Hardox 400 steel plates using the CO2 laser. The purpose of the investigation was to investigate the relationship between the entropy and the hardness of machined surfaces. [...] Read more.
The article presents the findings of a study on the machining of 10 mm thick Hardox 400 steel plates using the CO2 laser. The purpose of the investigation was to investigate the relationship between the entropy and the hardness of machined surfaces. For this purpose, a new mathematical model is established to estimate the entropy, and its influence on the hardness is determined. The mathematical model is statistically and experimentally validated. An entropy variation ΔS = −330 mJ/K between 2 K is found, causing a decrease in hardness compared to the standard value. The influences of input parameters (laser power, cutting speed, and auxiliary gas pressure) on hardness are determined. It is demonstrated that the surface hardness is strongly influenced by the auxiliary gas pressure. The combination of laser power P = 4200 W with gas pressure p = 0.45 bar at average cutting speed v = 1400 mm/min leads to a hardness of 38 HRC, extending the life and wear resistance of the cut parts. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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15 pages, 5010 KiB  
Article
Effect of Heat Input on Microstructure and Mechanical Properties of Deposited Metal of E120C-K4 High Strength Steel Flux-Cored Wire
by Wen Wu, Tianli Zhang, Haoxin Chen, Jingjing Peng, Kaiqin Yang, Sanbao Lin, Peiyin Wen, Zhuoxin Li, Shanglei Yang and Sindo Kou
Materials 2023, 16(8), 3239; https://doi.org/10.3390/ma16083239 - 20 Apr 2023
Viewed by 1164
Abstract
The effect of different heat inputs of 1.45 kJ/mm, 1.78 kJ/mm and 2.31 kJ/mm on the microstructure and mechanical properties of deposited metals of the self-developed AWS A5.28 E120C-K4 high strength steel flux-cored wire was studied by optical microscope, scanning electron microscope and [...] Read more.
The effect of different heat inputs of 1.45 kJ/mm, 1.78 kJ/mm and 2.31 kJ/mm on the microstructure and mechanical properties of deposited metals of the self-developed AWS A5.28 E120C-K4 high strength steel flux-cored wire was studied by optical microscope, scanning electron microscope and mechanical property test. With the increase in heat input, the results showed that the microstructure of deposited metals became coarse. Acicular ferrite increased at first and then decreased, granular bainite increased and degenerated upper bainite and martensite decreased slightly. Under the low heat input of 1.45 kJ/mm, the cooling rate was fast and the element diffusion was uneven, which caused composition segregation and easy to form large size inclusions SiO2-TiC-CeAlO3 with weak binding to the matrix. Under the middle heat input of 1.78 kJ/mm, the composite rare earth inclusions in dimples were mainly TiC-CeAlO3. The dimples were small and uniformly distributed, and the dimple fracture mainly depended on the wall-breaking connection between medium-sized dimples rather than an intermediate media. Under the high heat input of 2.31 kJ/mm, SiO2 was easy to adhere to high melting point Al2O3 oxides to form irregular composite inclusions. Such irregular inclusions do not need to absorb too much energy to form necking. Finally, the integrated effects of microstructure and inclusions resulted in the optimum mechanical properties of deposited metals with a heat input of 1.78 kJ/mm, which was a tensile strength of 793 MPa and an average impact toughness at −40 °C of 56 J. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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12 pages, 7059 KiB  
Article
One-Pot Fabrication of Nanocomposites Composed of Carbon Nanotubes and Alumina Powder Using a Rotatable Chemical Vapor Deposition System
by Jong-Hwan Lee, Hyun-Ho Han, Jong-Min Seo and Goo-Hwan Jeong
Materials 2023, 16(7), 2735; https://doi.org/10.3390/ma16072735 - 29 Mar 2023
Cited by 1 | Viewed by 1209
Abstract
The fabrication of multi-dimensional nanocomposites has been extensively attempted to achieve synergistic performance through the uniform mixing of functional constituents. Herein, we report a one-pot fabrication of nanocomposites composed of carbon nanotubes (CNTs) and Al2O3 powder. Our strategy involves a [...] Read more.
The fabrication of multi-dimensional nanocomposites has been extensively attempted to achieve synergistic performance through the uniform mixing of functional constituents. Herein, we report a one-pot fabrication of nanocomposites composed of carbon nanotubes (CNTs) and Al2O3 powder. Our strategy involves a synthesis of CNTs on the entire Al2O3 surface using a rotatable chemical vapor deposition system (RCVD). Ehylene and ferritin-induced nanoparticles were used as the carbon source and wet catalyst, respectively. The RCVD was composed of a quartz reaction tube, 5.08 cm in diameter and 150 cm in length, with a rotation speed controller. Ferritin dissolved in deionized water was uniformly dispersed on the Al2O3 surface and calcinated to obtain iron nanoparticles. The synthesis temperature, time, and rotation speed of the chamber were the main parameters used to investigate the growth behavior of CNTs. We found that the CNTs can be grown at least around 600 °C, and the number of tubes increases with increasing growth time. A faster rotation of the chamber allows for the uniform growth of CNT by the tip-growth mechanism. Our results are preliminary at present but show that the RCVD process is sufficient for the fabrication of powder-based nanocomposites. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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13 pages, 5932 KiB  
Article
Effect of Al Concentration on Basal Texture Formation Behavior of AZ-Series Magnesium Alloys during High-Temperature Deformation
by Kibeom Kim, Yebin Ji, Kwonhoo Kim and Minsoo Park
Materials 2023, 16(6), 2380; https://doi.org/10.3390/ma16062380 - 16 Mar 2023
Cited by 1 | Viewed by 1029
Abstract
Magnesium and its alloys have been restricted in their industrial applications due to problems related to their formability. To overcome this issue, controlling the crystallographic texture is important, and the texture formation mechanism should be investigated in relation to factors including deformation conditions [...] Read more.
Magnesium and its alloys have been restricted in their industrial applications due to problems related to their formability. To overcome this issue, controlling the crystallographic texture is important, and the texture formation mechanism should be investigated in relation to factors including deformation conditions and solute atoms. In particular, the effects of solute atoms on the texture formation behavior should be further analyzed because they can considerably affect the deformation behavior. Thus, in this study, to clarify the effect of aluminum concentration on the texture formation behavior and microstructure, high-temperature uniaxial compression tests were conducted on three types of AZ-series magnesium alloys (AZ31, AZ61, and AZ91). Compression was conducted at 673 K and 723 K, with strain rates of 0.05 s−1 and 0.005 s−1, up to a true strain of −1.0. Cylindrical specimens were prepared from a rolled plate that had a (0001) basal texture and was compressed parallel to the c-axis of the grains. Consequently, work softening and fiber texture formation were observed in all the specimens. During the deformation, the development of grain boundaries, which is a typical characteristic of continuous dynamic recrystallization (CDRX), was observed, and the (0001) texture was highly developed with increasing Al content. Although each alloy was associated with the same deformation conditions and mechanisms, the AZ31 alloy exhibited a non-basal texture component. The stacking fault energy contributed to the generation of slip systems and gliding, and it was seen as the main reason for texture variation. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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17 pages, 7151 KiB  
Article
Experimental Investigation of Milling Performance of Silicon Nitride Ceramic Subject to Different Assisted Systems
by Muhammad Naveed Raza and Shen-Yung Lin
Materials 2023, 16(1), 137; https://doi.org/10.3390/ma16010137 - 23 Dec 2022
Cited by 2 | Viewed by 1195
Abstract
In this study, silicon nitride milling experiments are carried out using Polycrystalline Diamond (PCD) end mill rods under unassisted, hybrid-assisted (combination of laser assisted and three axis ultrasound), and laser-assisted systems to examine the cutting performance and machined surface quality of different cutting [...] Read more.
In this study, silicon nitride milling experiments are carried out using Polycrystalline Diamond (PCD) end mill rods under unassisted, hybrid-assisted (combination of laser assisted and three axis ultrasound), and laser-assisted systems to examine the cutting performance and machined surface quality of different cutting tools. The best combination of process parameters for silicon nitride composites milling are obtained using the Taguchi method. The effects of spindle speed, radial depth of cut, and feed rate on surface roughness, cutting force, edge topography, and tool wear of silicon nitride surfaces are investigated. The results reveal that hybrid-assisted produces superior surface roughness, longer tool life, fewer machining defects, and lower cutting force than unassisted. Best results of triaxial ultrasonic-assisted combined with laser on cutting performance are achieved as the ultrasonic waves help to vibrate the cutting tool and workpiece simultaneously, which helps to effectively remove chips and lowers the cutting force. When compared to unassisted milling, laser-assisted and hybrid-assisted milling improve total average surface roughness by 42% and 66%, and total cutting forces by 26% and 46%, respectively. The best processing parameters obtained in this study are high spindle speed (12,000 rpm), low feed rate (500 mm/min), and low cutting depth (0.02 mm). Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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24 pages, 10692 KiB  
Article
A New Hydrometallurgical Process for Metal Extraction from Electric Arc Furnace Dust Using Ionic Liquids
by Samaneh Teimouri, Johannes Herman Potgieter, Mari Lundström, Caren Billing and Benjamin P. Wilson
Materials 2022, 15(23), 8648; https://doi.org/10.3390/ma15238648 - 04 Dec 2022
Cited by 4 | Viewed by 1778
Abstract
This research proposes a new hydrometallurgical method for Zn, In, and Ga extraction, along with Fe as a common impurity, from electric arc furnace dust (EAFD), using ionic liquids. EAFD is a metal-containing waste fraction generated in significant amounts during the process of [...] Read more.
This research proposes a new hydrometallurgical method for Zn, In, and Ga extraction, along with Fe as a common impurity, from electric arc furnace dust (EAFD), using ionic liquids. EAFD is a metal-containing waste fraction generated in significant amounts during the process of steelmaking from scrap material in an electric arc furnace. With valuable metal recovery as the main goal, two ionic liquids, [Bmim+HSO4] and [Bmim+Cl], were studied in conjunction with three oxidants: Fe2(SO4)3, KMnO4, and H2O2. The results indicated that the best combination was [Bmim+HSO4] with [Fe2(SO4)3]. An experimental series subsequently demonstrated that the combination of 30% v/v [Bmim+HSO4], 1 g of [Fe2(SO4)3], S/L ratio = 1/20, a 240 min leaching time, and a temperature of 85 °C was optimal, resulting in maximum extractions of 92.7% Zn, 97.4% In, and 17.03% Ga. In addition, 80.2% of the impurity metal Fe was dissolved. The dissolution kinetics of these four elements over a temperature range of 55–85 °C was found to be diffusion controlled. The remaining phases present in the leached residue were low amounts of ZnO, Fe3O4, ZnFe2O4, and traces of Ca(OH)2 and MnO2, and additional sharp peaks indicative of PbSO4 and CaSO4 appeared within the XRD pattern. The intensity of the peaks related to ZnO and Fe3O4 were observed to have decreased considerably during leaching, whereas some of the refractory ZnFe2O4 phase remained. SEM-EDS analysis revealed that the initial EAFD morphology was composed of spherical-shaped fine-grained particle agglomerates, whereas the leached residue was dominated by calcium sulphate (Ca(SO4))-rich needle-shaped crystals. The results clearly demonstrate that [Bmim+HSO4] is able to extract the target metals due to its acidic properties. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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10 pages, 5140 KiB  
Article
Influence of Tempering Temperature and Time on Microstructure and Mechanical Properties of Additively Manufactured H13 Tool Steel
by Kichang Bae, Hyoung-Seok Moon, Yongho Park, Ilguk Jo and Junghoon Lee
Materials 2022, 15(23), 8329; https://doi.org/10.3390/ma15238329 - 23 Nov 2022
Cited by 5 | Viewed by 1488
Abstract
Among various processes for manufacturing complex-shaped metal parts, additive manufacturing is highlighted as a process capable of reducing the wastage of materials without requiring a post-process, such as machining and finishing. In particular, it is a suitable new manufacturing technology for producing AISI [...] Read more.
Among various processes for manufacturing complex-shaped metal parts, additive manufacturing is highlighted as a process capable of reducing the wastage of materials without requiring a post-process, such as machining and finishing. In particular, it is a suitable new manufacturing technology for producing AISI H13 tool steel for hot-worked molds with complex cooling channels. In this study, we manufactured AISI H13 tool steel using the laser power bed fusion (LPBF) process and investigated the effects of tempering temperature and holding time on its microstructure and mechanical properties. The mechanical properties of the sub-grain cell microstructure of the AISI H13 tool steel manufactured using the LPBF process were superior to that of the H13 tool steel manufactured using the conventional method. These sub-grain cells decomposed and disappeared during the austenitizing process; however, the mechanical properties could be restored at a tempering temperature of 500 °C or higher owing to the secondary hardening and distribution of carbides. Furthermore, the mechanical properties deteriorated because of the decomposition of the martensite phase and the accumulation and coarsening of carbides when over-tempering occurred at 500 °C for 5 h and 550 °C for 3 h. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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28 pages, 4243 KiB  
Article
Simulation of Melting Efficiency in Laser Cutting of Hardox 400 Steel
by Constantin Cristinel Girdu and Catalin Gheorghe
Materials 2022, 15(20), 7192; https://doi.org/10.3390/ma15207192 - 15 Oct 2022
Cited by 1 | Viewed by 1436
Abstract
Laser cutting has experienced a sharp development in recent years due to the advantages it implies in industrial production, the most important being: great diversity of processed materials, reduced cutting time, low processing cost, small percentage of removed material, and low impact on [...] Read more.
Laser cutting has experienced a sharp development in recent years due to the advantages it implies in industrial production, the most important being: great diversity of processed materials, reduced cutting time, low processing cost, small percentage of removed material, and low impact on the natural environment. The problem of energy has become acute in the last year, so a new direction of research has taken shape, consisting of the optimization of the high energy consumptions involved in laser cutting. The objective of this research is to develop a computational and experimental model to estimate the melting efficiency. Additionally, the research seeks to establish some mathematical relationships that describe the law of variation of the melting efficiency depending on the input parameters in the CO2 laser cutting. The experimental determinations were carried out on Hardox 400 steel plates of 8 mm thickness. The input parameters were laser power, assist gas pressure, and cutting speed. The experimental data were statistically processed, and the results were verified with the Lagrange interpolation method. It was found that the maximum melting efficiency is influenced mainly by laser power (F = 3.06; p = 0.049), followed by speed and pressure. The results obtained show that the melting efficiency varies in the range (13.6–20.68) mm3/KJ. The maximum value of the melting efficiency (20 J/mm3) was obtained when the laser power was 5100 W, the cutting speed 1900 mm/min, and the gas pressure 0.5 bar, and the minimum efficiency under conditions of speed setting at 1700 mm/min and laser power of 5000 W. Linear and quadratic regression models were established to estimate the global mean efficiency according to two independent variables that act at the same time. The established calculation relationships contribute to the improvement of the literature and constitute a tool for practical applications. The results obtained allow the modeling of cutting parameters and the optimization of production costs in industrial processes that use laser cutting. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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14 pages, 4534 KiB  
Article
Kinetics of Magnesiothermic Reduction of Natural Quartz
by Azam Rasouli, Maria Tsoutsouva, Jafar Safarian and Gabriella Tranell
Materials 2022, 15(19), 6535; https://doi.org/10.3390/ma15196535 - 21 Sep 2022
Cited by 3 | Viewed by 1071
Abstract
In this work, the kinetics of natural quartz reduction by Mg to produce either Si or Mg2Si was studied through quantitative phase analysis. Reduction reaction experiments were performed at various temperatures, reaction times and Mg to SiO2 mole ratios of [...] Read more.
In this work, the kinetics of natural quartz reduction by Mg to produce either Si or Mg2Si was studied through quantitative phase analysis. Reduction reaction experiments were performed at various temperatures, reaction times and Mg to SiO2 mole ratios of 2 and 4. Rietveld refinement of X-ray diffraction patterns was used to obtain phase distributions in the reacted samples. SEM and EPMA examinations were performed to evaluate the microstructural change during reduction. The results indicated that the reduction reaction rate was slower at a mole ratio of 2 than 4 at the same temperature, as illustrated by the total amount of Si formed (the percent of Si that is reduced to either Si or Mg2Si to total amount of Si) being 59% and 75%, respectively, after 240 min reaction time for mole ratios of 2 and 4. At the mole ratio of 4, the reaction rate was strongly dependent on the reaction temperature, where SiO2 was completely reduced after 20 min at 1273 K. At the lower temperatures of 1173 and 1073 K, total Si formed was 75% and 39%, respectively, after 240 min reaction time. The results of the current work show that Mg2Si can be produced through the magnesiothermic reduction of natural quartz with high yield. The obtained Mg2Si can be processed further to produce silane gas as a precursor to high purity Si. The combination of these two processes offers the potential for a more direct and low carbon method to produce Si with high purity. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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12 pages, 2776 KiB  
Article
Corrosion Resistance of Laser Powder Bed Fused AISI 316L Stainless Steel and Effect of Direct Annealing
by Kichang Bae, Dongmin Shin, Jonghun Lee, Seohan Kim, Wookjin Lee, Ilguk Jo and Junghoon Lee
Materials 2022, 15(18), 6336; https://doi.org/10.3390/ma15186336 - 13 Sep 2022
Cited by 3 | Viewed by 1528
Abstract
Alloy parts produced by an additive manufacturing method with rapid heat transfer from fast melting and solidification have different microstructures, characteristics, and performances compared with materials made by the conventional process. In this study, the corrosion and oxidation resistance of SS316L, which was [...] Read more.
Alloy parts produced by an additive manufacturing method with rapid heat transfer from fast melting and solidification have different microstructures, characteristics, and performances compared with materials made by the conventional process. In this study, the corrosion and oxidation resistance of SS316L, which was prepared by the powder bed fusion process, was compared with those of cold-rolled SS316L. Additionally, the surface oxide film on stainless steel was thoroughly assessed since the film has the greatest influence on the corrosion and oxidation resistance. The effect of heat treatment on corrosion and oxidation resistance of SS316L fabricated by additive manufacturing was investigated. The SS316L has a microstructure formed by sub-grain cells, in which locally concentrated alloying elements form a stable passive film. As a result, it has a higher level of corrosion resistance and oxidation resistance than conventional cold-rolled materials. However, it was confirmed that the sub-grain cell was removed by heat treatment, which resulted in the degradation of corrosion and oxidation resistance. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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13 pages, 7602 KiB  
Article
Effect of Ca Precipitation on Texture Component Development in AZ Magnesium Alloy
by Kibeom Kim, Yebin Ji and Kwonhoo Kim
Materials 2022, 15(15), 5367; https://doi.org/10.3390/ma15155367 - 04 Aug 2022
Cited by 2 | Viewed by 1191
Abstract
To enhance the formability of magnesium alloys, inhibition of basal texture development by the particle-stimulated nucleation (PSN) effect has attracted significant interest. However, its contribution to texture development is not easily observed due to the separation of texture from the conventional deformation behavior. [...] Read more.
To enhance the formability of magnesium alloys, inhibition of basal texture development by the particle-stimulated nucleation (PSN) effect has attracted significant interest. However, its contribution to texture development is not easily observed due to the separation of texture from the conventional deformation behavior. This study aims to separate the Ca texture from the deformation behavior of AZX611 alloy and quantify it using scanning electron microscopy with electron backscatter diffraction (SEM-EBSD). Since Ca in the AZ61 magnesium alloy precipitated as Al2Ca, the hot-rolled magnesium alloys AZ31, AZ61, and AZX611 were used. High temperature compression was conducted at 723 K, the strain rate 0.05/s and 0.005/s and the true strain up to −1.0. Dynamic recrystallization was observed in each specimen and the Ca-free alloys showed dislocation glide at high strain rates and solute drag at low strain rates. When the dislocation glide dominated, basal texture was strengthened. In contrast, solute drag caused non-basal texture development. Precipitation hardening caused AZ61 to have higher flow stress than those of the Ca-free alloys by the PSN effect; its texture was observed separately because the PSN grain growth around the precipitation and orientation was specific, similar to the one developed at the solute atom drag. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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15 pages, 8309 KiB  
Article
Microstructure and Mechanical Properties of an Al–Mg–Si–Zr Alloy Processed by L-PBF and Subsequent Heat Treatments
by Wonseok Yang, Young-Gil Jung, Taeyang Kwak, Shae K. Kim, Hyunkyu Lim and Do-Hyang Kim
Materials 2022, 15(15), 5089; https://doi.org/10.3390/ma15155089 - 22 Jul 2022
Cited by 4 | Viewed by 1212
Abstract
The aim of this study was to develop a new Al–Mg–Si–Zr alloy with a high magnesium content to achieve a wide range of mechanical properties using heat treatment and at a lower cost. Additive manufacturing was conducted using a powder bed fusion process [...] Read more.
The aim of this study was to develop a new Al–Mg–Si–Zr alloy with a high magnesium content to achieve a wide range of mechanical properties using heat treatment and at a lower cost. Additive manufacturing was conducted using a powder bed fusion process with various scan speeds to change the volumetric energy density and establish optimal process conditions. In addition, mechanical properties were evaluated using heat treatment under various conditions. The characterization of the microstructure was conducted by scanning electron microscopy with electron backscatter diffraction and transmission electron microscopy. The mechanical properties were determined by tensile tests. The as-built specimen showed a yield strength of 447.9 ± 3.6 MPa, a tensile strength of 493.4 ± 6.7 MPa, and an elongation of 9.6 ± 1.1%. Moreover, the mechanical properties could be adjusted according to various heat treatment conditions. Specifically, under the HT1 (low-temperature artificial aging) condition, the ultimate tensile strength increased to 503.2 ± 1.1 MPa, and under the HT2 (high-temperature artificial aging) condition, the yield strength increased to 467 ± 1.3 MPa. It was confirmed that the maximum elongation (14.3 ± 0.8%) was exhibited with the HT3 (soft annealing) heat treatment. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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8 pages, 971 KiB  
Article
Surface Cleaning Effect of Bare Aluminum Micro-Sized Powder by Low Oxygen Induction Thermal Plasma
by Dasom Kim, Yusuke Hirayama, Kenta Takagi and Hansang Kwon
Materials 2022, 15(4), 1553; https://doi.org/10.3390/ma15041553 - 18 Feb 2022
Cited by 2 | Viewed by 1296
Abstract
The development of bare metal powder is desirable for obtaining conductive interfaces by low-temperature sintering to be applied in various industries of 3D printing, conductive ink or paste. In our previous study, bulk Al made from Al nanopowder that was prepared with low-oxygen [...] Read more.
The development of bare metal powder is desirable for obtaining conductive interfaces by low-temperature sintering to be applied in various industries of 3D printing, conductive ink or paste. In our previous study, bulk Al made from Al nanopowder that was prepared with low-oxygen thermal plasma (LO-ITP), which is the original metal powder production technique, showed high electrical conductivity comparable to Al casting material. This study discusses the surface cleaning effect of Al particles expected to be obtained by peeling the surface of Al particles using the LO-ITP method. Bare metal micro-sized powders were prepared using LO-ITP by controlling the power supply rate and preferentially vaporizing the oxidized surface of the Al powder. Electrical conductivity was evaluated to confirm if there was an oxide layer at the Al/Al interface. The Al compact at room temperature produced from LO-ITP-processed Al powder showed an electrical conductivity of 2.9 · 107 S/m, which is comparable to that of cast Al bulk. According to the microstructure observation, especially for the interfaces between bare Al powder, direct contact was achieved at 450 °C sintering. This process temperature is lower than the conventional sintering temperature (550 °C) of commercial Al powder without any surface cleaning. Therefore, surface cleaning using LO-ITP is the key to opening a new gate to the powder metallurgy process. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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20 pages, 9072 KiB  
Article
In Situ Observation of Microstructural and Inclusions Evolution in High-Strength Steel Deposited Metals with Various Rare Earth Pr Contents
by Tianli Zhang, Weiguang Wang, Yiming Ma, Naiwen Fang, Sanbao Lin, Zhuoxin Li and Sindo Kou
Materials 2022, 15(3), 1257; https://doi.org/10.3390/ma15031257 - 08 Feb 2022
Cited by 4 | Viewed by 1488
Abstract
The evolution of austenite, acicular ferrite, upper bainite and martensite, and the nucleation of inclusions in the microstructure of high-strength steel deposited metals, was systematically investigated using three kinds of A5.28 E120C-K4 metal-cored wires with various rare earth Pr contents. Grain structure evolution [...] Read more.
The evolution of austenite, acicular ferrite, upper bainite and martensite, and the nucleation of inclusions in the microstructure of high-strength steel deposited metals, was systematically investigated using three kinds of A5.28 E120C-K4 metal-cored wires with various rare earth Pr contents. Grain structure evolution in the process of high temperature, dispersoid characteristics of inclusions and the crystallographic characteristics of the microstructure were assessed. Compared with no addition of Pr6O11, adding 1%Pr6O11 resulted in refined, spheroidized and dispersed inclusions in the deposited metal, leading to an increase in the pinning forces on the grain boundary movement, promoting the formation of an ultra-fine grain structure with an average diameter of 41 μm. The inclusions in the deposited metals were Mn-Si-Pr-Al-Ti-O after Pr addition; the average size of the inclusions in the Pr-containing deposited metals was the smallest, while the number and density of inclusions was the highest. The size of effective inclusions (nucleus of acicular ferrite formation) was mainly in the range of 0.6–1.5 μm. In addition, the content of upper bainite decreased, while the percentage of acicular ferrite increased by 24% due to the increase in the number of effective inclusions in the Pr-containing deposited metals in this study. This study shows that the addition of 1% Pr6O11 is efficient in achieving fine interlaced multiphase with an ultrafine-grained structure, resulting in an enhancement of the impact toughness of the deposited metal. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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9 pages, 3943 KiB  
Article
Ethanol-Induced Flash Sintering of ZnO Ceramics at Room Temperature
by Nianping Yan, Jianbing Pan, Zhixiang Deng, Muliang Cai, Xinhao Zhao, Jieming Liu, Xilin Wang and Zhidong Jia
Materials 2022, 15(3), 862; https://doi.org/10.3390/ma15030862 - 23 Jan 2022
Cited by 2 | Viewed by 2044
Abstract
Ceramic flash sintering with a strong electric field at room temperature is the most attractive method. This paper presents the flash sintering of ZnO ceramics at room temperature by the application of a 3-kV/cm electric field after a dropwise addition of ethanol. This [...] Read more.
Ceramic flash sintering with a strong electric field at room temperature is the most attractive method. This paper presents the flash sintering of ZnO ceramics at room temperature by the application of a 3-kV/cm electric field after a dropwise addition of ethanol. This method is simple and easy to control. The density of the specimen exceeded 96% after 30 s of sintering. No significant difference was observed in the initiation voltage of flash sintering with and without the dropwise addition of ethanol. Ethanol burns upon dropwise addition, causing a discharge to first occur far from the location of the dropwise addition, followed by glowing and heating up, which causes the temperature of the entire specimen to rise. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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15 pages, 4216 KiB  
Article
Manganese and Aluminium Recovery from Ferromanganese Slag and Al White Dross by a High Temperature Smelting-Reduction Process
by Artur Kudyba and Jafar Safarian
Materials 2022, 15(2), 405; https://doi.org/10.3390/ma15020405 - 06 Jan 2022
Cited by 2 | Viewed by 1808
Abstract
The recovery of Mn and Al from two industrial waste of ferromanganese and aluminum production processes was investigated via implementing a high temperature smelting—aluminothermic reduction process. The experiments were carried out with or without CaO flux addition, and two dross qualities. It was [...] Read more.
The recovery of Mn and Al from two industrial waste of ferromanganese and aluminum production processes was investigated via implementing a high temperature smelting—aluminothermic reduction process. The experiments were carried out with or without CaO flux addition, and two dross qualities. It was observed that the prepared mixtures of the materials yield homogeneous metal and slag products in terms of chemical composition and the distribution of phases. However, the separation of produced metal phase from the slag at elevated temperatures occurs when a higher amount of CaO is added. Viscosity calculations and equilibrium study indicated that the better metal and slag separation is obtained when the produced slag has lower viscosity and lower liquidus. It was found that the process yields Al-Mn-Si alloys, and it is accompanied with complete recovery of Mn, Si and Fe and the unreacted Al in the process. Moreover, the quality of metal product was less dependent on the slightly different dross quality, and the concentration of minor Ca in metal is slightly increased with significant increase of CaO in the slag phase. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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11 pages, 8643 KiB  
Article
Metallothermic Reduction of MoO3 on Combustion Synthesis of Molybdenum Silicides/MgAl2O4 Composites
by Chun-Liang Yeh and Min-Chia Chen
Materials 2021, 14(17), 4800; https://doi.org/10.3390/ma14174800 - 24 Aug 2021
Cited by 4 | Viewed by 1747
Abstract
Combustion synthesis involving metallothermic reduction of MoO3 by dual reductants, Mg and Al, to enhance the reaction exothermicity was applied for the in situ production of Mo3Si–, Mo5Si3− and MoSi2–MgAl2O4 composites [...] Read more.
Combustion synthesis involving metallothermic reduction of MoO3 by dual reductants, Mg and Al, to enhance the reaction exothermicity was applied for the in situ production of Mo3Si–, Mo5Si3− and MoSi2–MgAl2O4 composites with a broad compositional range. Reduction of MoO3 by Mg and Al is highly exothermic and produces MgO and Al2O3 as precursors of MgAl2O4. Molybdenum silicides are synthesized from the reactions of Si with both reduced and elemental Mo. Experimental evidence indicated that the reaction proceeded as self-propagating high-temperature synthesis (SHS) and the increase in silicide content weakened the exothermicity of the overall reaction, and therefore, lowered combustion front temperature and velocity. The XRD analysis indicated that Mo3Si–, Mo5Si3– and MoSi2–MgAl2O4 composites were well produced with only trivial amounts of secondary silicides. Based on SEM and EDS examinations, the morphology of synthesized composites exhibited dense and connecting MgAl2O4 crystals and micro-sized silicide particles, which were distributed over or embedded in the large MgAl2O4 crystals. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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13 pages, 5289 KiB  
Article
Interdiffusion and Intermetallic Compounds at Al/Cu Interfaces in Al-50vol.%Cu Composite Prepared by Solid-State Sintering
by Dasom Kim, Kyungju Kim and Hansang Kwon
Materials 2021, 14(15), 4307; https://doi.org/10.3390/ma14154307 - 31 Jul 2021
Cited by 6 | Viewed by 1860
Abstract
Al–Cu composites have attracted significant interest recently owing to their lightweight nature and remarkable thermal properties. Understanding the interdiffusion mechanism at the numerous Al/Cu interfaces is crucial to obtain Al–Cu composites with high thermal conductivities. The present study systematically investigates the interdiffusion mechanism [...] Read more.
Al–Cu composites have attracted significant interest recently owing to their lightweight nature and remarkable thermal properties. Understanding the interdiffusion mechanism at the numerous Al/Cu interfaces is crucial to obtain Al–Cu composites with high thermal conductivities. The present study systematically investigates the interdiffusion mechanism at Al/Cu interfaces in relation to the process temperature. Al-50vol.%Cu composite powder, where Cu particles were encapsulated in a matrix of irregular Al particles, was prepared and then sintered at various temperatures from 340 to 500 °C. Intermetallic compounds (ICs) such as CuAl2 and Cu9Al4 were formed at the Al/Cu interfaces during sintering. Microstructural analysis showed that the thickness of the interdiffusion layer, which comprised the CuAl2 and Cu9Al4 ICs, drastically increased above 400 °C. The Vickers hardness of the Al-50vol.%Cu composite sintered at 380 °C was 79 HV, which was 1.5 times that of the value estimated by the rule of mixtures. A high thermal conductivity of 150 W∙m−1∙K−1 was simultaneously obtained. This result suggests that the Al-50vol.%Cu composite material with large number of Al/Cu interfaces, as well as good mechanical strength and heat conductance, can be prepared by solid-state sintering at a low temperature. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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18 pages, 8558 KiB  
Article
Valorization of Aluminum Dross with Copper via High Temperature Melting to Produce Al-Cu Alloys
by Artur Kudyba, Shahid Akhtar, Inge Johansen and Jafar Safarian
Materials 2021, 14(15), 4117; https://doi.org/10.3390/ma14154117 - 23 Jul 2021
Cited by 5 | Viewed by 2087
Abstract
The valorization of aluminum dross for Al recovery was performed via its mixing with metallic copper to produce Al-Cu alloys. This approach was with the intention of establishing a new smelting process to treat the dross with Cu scrap use. To evaluate the [...] Read more.
The valorization of aluminum dross for Al recovery was performed via its mixing with metallic copper to produce Al-Cu alloys. This approach was with the intention of establishing a new smelting process to treat the dross with Cu scrap use. To evaluate the high temperature interaction of the materials, the wettability of a Cu-containing aluminum alloy with the non-metallic components of the dross was studied by the sessile drop method. It was found that the wetting was weak via temperature changes at 973–1373 K, and consequently no proper metal separation occurred. To better separate the metallic and non-metallic phases with larger density differences, a higher Cu portion was considered to obtain a significantly denser metallic phase, and it was found that partial separation of the Al in an Al-Cu alloy is possible. The complete separation of the metallic components of the dross was, however, experienced by the dross and copper melting with the addition of pre-melted calcium aluminate slags at elevated temperatures. It was found that Al-Cu alloys were produced and separated from the adjacent slags, and the aluminum oxide of the dross ended up in the slag phase. Moreover, the characteristics of the produced slags depend on the process charge. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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14 pages, 4462 KiB  
Article
Study on X-ray Induced Two-Dimensional Thermal Shock Waves in Carbon/Phenolic
by Dengwang Wang, Yong Gao, Sheng Wang, Jie Wang and Haipeng Li
Materials 2021, 14(13), 3553; https://doi.org/10.3390/ma14133553 - 25 Jun 2021
Cited by 2 | Viewed by 1273
Abstract
Carbon/Phenolic (C/P), a typical anisotropic material, is an important component of aerospace and often used to protect the thermodynamic effects of strong X-ray radiation. In this paper, we establish the anisotropic elastic-plastic constitutive model, which is embedded in the in-house code “RAMA” to [...] Read more.
Carbon/Phenolic (C/P), a typical anisotropic material, is an important component of aerospace and often used to protect the thermodynamic effects of strong X-ray radiation. In this paper, we establish the anisotropic elastic-plastic constitutive model, which is embedded in the in-house code “RAMA” to simulate a two-dimensional thermal shock wave induced by X-ray. Then, we compare the numerical simulation results with the thermal shock wave stress generated by the same strong current electron beam via experiment to verify the correctness of the numerical simulation. Subsequently, we discuss and analyze the rules of thermal shock wave propagation in C/P material by further numerical simulation. The results reveal that the thermal shock wave represents different shapes and mechanisms by the radiation of 1 keV and 3 keV X-rays. The vaporization recoil phenomenon appears as a compression wave under 1 keV X-ray irradiation, and X-ray penetration is caused by thermal deformation under 3 keV X-ray irradiation. The thermal shock wave propagation exhibits two-dimensional characteristics, the energy deposition of 1 keV and 3 keV both decays exponentially, the energy deposition of 1 keV-peak soft X-ray is high, and the deposition depth is shallow, while the energy deposition of 3 keV-peak hard X-ray is low, and the deposition depth is deep. RAMA can successfully realize two-dimensional orthotropic elastoplastic constitutive relation, the corresponding program was designed and checked, and the calculation results for inspection are consistent with the theory. This study has great significance in the evaluation of anisotropic material protection under the radiation of intense X-rays. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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10 pages, 1035 KiB  
Article
Research on the Release of Dangerous Compounds from the BTEX and PAHs Groups in Industrial Casting Conditions
by Mariusz Holtzer, Rafał Dańko, Sylwester Piasny, Michał Kubecki, Dariusz Drożyński, Agnieszka Roczniak, Mateusz Skrzyński and Angelika Kmita
Materials 2021, 14(10), 2581; https://doi.org/10.3390/ma14102581 - 16 May 2021
Cited by 3 | Viewed by 1460
Abstract
The assessment of the harmfulness of moulding and core sands is mainly based on investigations of compositions of gases emitted by liquid casting alloys during the mould pouring. The results of investigations of moulding sands obtained under industrial conditions are presented in this [...] Read more.
The assessment of the harmfulness of moulding and core sands is mainly based on investigations of compositions of gases emitted by liquid casting alloys during the mould pouring. The results of investigations of moulding sands obtained under industrial conditions are presented in this paper. A unique research stand was designed and built for this aim. It allowed us to determine emissions of gases at individual stages of casting a mass up to 50 kg. This approach enables simulation of foundry conditions. Moulding sands bound by organic binders (phenol-formaldehyde; furan), inorganic binders and green sand, were subjected to investigations. The composition of gases that evolved during the individual stages, pouring, cooling and knocking out, was tested each time, and the contents of Polycyclic Aromatic Hydrocarbons (PAHs) and benzene, toluene, ethylbenzene, and xylenes (BETX) were analysed. Investigations indicated that the emission of gases from sands with inorganic binders is negligible when compared with the emission of gases from sands with organic binders. The emission of gases from green sand is placed in the middle of the scale. As an example: the sand with furan resin emitted 84 mg of BTEX (in recalculation for 1 kg of sand) while from sands with inorganic binders there was a maximum of 2.2 mg (for 1 kg of sand). In the case of sands with inorganic binders, MI and MC sands indicated comparable and very low emissions of gases from the PAHs group, at the level of 0.018 mg and 0.019 mg for 1 kg of sand, respectively. The higher emission of PAHs from MG sand is the result of its different way of hardening (a binder was of an organic character) than of sands MI and MC. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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Review

Jump to: Research

33 pages, 8347 KiB  
Review
Recent Advances in Processing of Titanium and Titanium Alloys through Metal Injection Molding for Biomedical Applications: 2013–2022
by Al Basir, Norhamidi Muhamad, Abu Bakar Sulong, Nashrah Hani Jamadon and Farhana Mohd Foudzi
Materials 2023, 16(11), 3991; https://doi.org/10.3390/ma16113991 - 26 May 2023
Cited by 6 | Viewed by 2394
Abstract
Metal injection molding (MIM) is one of the most widely used manufacturing processes worldwide as it is a cost-effective way of producing a variety of dental and orthopedic implants, surgical instruments, and other important biomedical products. Titanium (Ti) and Ti alloys are popular [...] Read more.
Metal injection molding (MIM) is one of the most widely used manufacturing processes worldwide as it is a cost-effective way of producing a variety of dental and orthopedic implants, surgical instruments, and other important biomedical products. Titanium (Ti) and Ti alloys are popular modern metallic materials that have revamped the biomedical sector as they have superior biocompatibility, excellent corrosion resistance, and high static and fatigue strength. This paper systematically reviews the MIM process parameters that extant studies have used to produce Ti and Ti alloy components between 2013 and 2022 for the medical industry. Moreover, the effect of sintering temperature on the mechanical properties of the MIM-processed sintered components has been reviewed and discussed. It is concluded that by appropriately selecting and implementing the processing parameters at different stages of the MIM process, defect-free Ti and Ti alloy-based biomedical components can be produced. Therefore, this present study could greatly benefit future studies that examine using MIM to develop products for biomedical applications. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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25 pages, 9755 KiB  
Review
Research Progress in Interfacial Characteristics and Strengthening Mechanisms of Rare Earth Metal Oxide-Reinforced Copper Matrix Composites
by Xuemin Fu, Jiaxin Jiang and Xiaosong Jiang
Materials 2022, 15(15), 5350; https://doi.org/10.3390/ma15155350 - 03 Aug 2022
Cited by 5 | Viewed by 1539
Abstract
The existence of a small amount of rare earth metal oxides (REMOs) can greatly affect the structure and function of copper matrix composites owing to improvement of surface and interface properties between REMOs and metal matrix, and there are still some challenges concerning [...] Read more.
The existence of a small amount of rare earth metal oxides (REMOs) can greatly affect the structure and function of copper matrix composites owing to improvement of surface and interface properties between REMOs and metal matrix, and there are still some challenges concerning interfaces and complex interfacial reactions. This review summarizes the interfacial characteristics and strengthening mechanisms of REMO-reinforced copper matrix composites, including fabrication methods for solving rare earth metal oxide-dispersion problems and characterization of the microstructure and properties of REMO-reinforced copper matrix composites. In particular, the strengthening effects of various rare earth metal oxide-reinforced copper matrix composites are systematically summarized. The interface characteristics of composites from a thermodynamics standpoint and the strengthening mechanism are emphatically investigated and discussed in order to help unveil design principles and to provide reference for future research of REMO-reinforced copper matrix composites. Full article
(This article belongs to the Special Issue Advances in Materials Processing (Second Volume))
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