Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147791
Jeongha Lee, Kun-Jae Lee
The HAp (hydroxyapatite) excellent ion exchange resin and has adsorption properties of heavy metals and organic materials. It is used as an adsorption material and as an organic drug-delivery material due to these characteristics, that are essentially controlled the specific surface area. In this paper, the specific surface area was controlled by adding polymers of polyvinylpyrrolidone (PVP), polystyrene beads (PSB), and polyethylene glycol (PEG). Through the USP process, the HAp powder is able to synthesize into the spherical shape, specific surface area, and pore were controlled by the properties of the polymers.
{"title":"The Effects of the Polymers as a Sacrificed Material for the Hydroxyapatite Powder Synthesized by an Ultrasonic Spray Pyrolysis Process","authors":"Jeongha Lee, Kun-Jae Lee","doi":"10.24425/amm.2024.147791","DOIUrl":"https://doi.org/10.24425/amm.2024.147791","url":null,"abstract":"The HAp (hydroxyapatite) excellent ion exchange resin and has adsorption properties of heavy metals and organic materials. It is used as an adsorption material and as an organic drug-delivery material due to these characteristics, that are essentially controlled the specific surface area. In this paper, the specific surface area was controlled by adding polymers of polyvinylpyrrolidone (PVP), polystyrene beads (PSB), and polyethylene glycol (PEG). Through the USP process, the HAp powder is able to synthesize into the spherical shape, specific surface area, and pore were controlled by the properties of the polymers.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140716444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147804
Ji-A Lee, Bong-Min Jin, Jeong-Whan Han
Sintered ore used as blast furnace burden materials is produced by mixing iron ore, coke, and limestone, then burning the coke and sintering the iron ore with the combustion heat. Among the coke charged, A particle size of 0.25 mm or less has an insignificant effect as a heat source and adhere to the surface of other materials to inhibit the reaction between oxygen and raw materials, thereby decreasing the quality of sintered ore. Therefore, to increase combustion efficiency, it is necessary to reduce the ratio of coke breeze in the charged coke. In this study, theoretical calculation, experiment and simulation were conducted to investigate the possibility of size classification by drag force in the process of dropping coke after being transported through a belt conveyor. The height of belt conveyor was at 1m, and velocity of the belt was 1.5, 2.3, and 2.6 m/s, which were considered as experimental variables. After falling, the distribution of coke particle size according to the horizontal travel distance was confirmed, and a fall trajectory prediction formula model was created through the drag model of polydisperse system and compared with the experimental and analysis results.
{"title":"Evaluation of Classification Possibility of Coke Breeze by Drag Force","authors":"Ji-A Lee, Bong-Min Jin, Jeong-Whan Han","doi":"10.24425/amm.2024.147804","DOIUrl":"https://doi.org/10.24425/amm.2024.147804","url":null,"abstract":"Sintered ore used as blast furnace burden materials is produced by mixing iron ore, coke, and limestone, then burning the coke and sintering the iron ore with the combustion heat. Among the coke charged, A particle size of 0.25 mm or less has an insignificant effect as a heat source and adhere to the surface of other materials to inhibit the reaction between oxygen and raw materials, thereby decreasing the quality of sintered ore. Therefore, to increase combustion efficiency, it is necessary to reduce the ratio of coke breeze in the charged coke. In this study, theoretical calculation, experiment and simulation were conducted to investigate the possibility of size classification by drag force in the process of dropping coke after being transported through a belt conveyor. The height of belt conveyor was at 1m, and velocity of the belt was 1.5, 2.3, and 2.6 m/s, which were considered as experimental variables. After falling, the distribution of coke particle size according to the horizontal travel distance was confirmed, and a fall trajectory prediction formula model was created through the drag model of polydisperse system and compared with the experimental and analysis results.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140718023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147803
Junho Lee, Namhyuk Seo, Sang-Hwa Lee, K. Euh, Singon Kang, S. Son, Seok-Jae Lee, Jae-Gil Jung
This study investigated the effect of adding Al–5Ti–1B grain refiner on the solidification microstructure and hot deformation behavior of direct-chill (DC) cast Al–Zn–Mg–Cu alloys. The grain refiner significantly decreased the grain size and modified the morphology. Fine-grained (FG) alloys with grain refiners exhibit coarse secondary phases with a reduced number density compared to coarse-grained (CG) alloys without grain refiners. Dynamic recrystallization (DRX) was enhanced at higher compression temperatures and lower strain rates in the CG and FG alloys. Both particle stimulated nucleation (PSN) and continuous dynamic recrystallization (CDRX) are enhanced in the FG alloys, resulting in decreased peak stress values (indicating DRX onset) at 450°C. The peak stress of the FG alloys was higher at 300-400°C than that of the CG alloys because of grain refinement hardening over softening by enhanced DRX.
{"title":"Effect of Al–5Ti–1B Addition on Solidification Microstructure and Hot Deformation Behavior of DC-Cast Al–Zn–Mg–Cu Alloy","authors":"Junho Lee, Namhyuk Seo, Sang-Hwa Lee, K. Euh, Singon Kang, S. Son, Seok-Jae Lee, Jae-Gil Jung","doi":"10.24425/amm.2024.147803","DOIUrl":"https://doi.org/10.24425/amm.2024.147803","url":null,"abstract":"This study investigated the effect of adding Al–5Ti–1B grain refiner on the solidification microstructure and hot deformation behavior of direct-chill (DC) cast Al–Zn–Mg–Cu alloys. The grain refiner significantly decreased the grain size and modified the morphology. Fine-grained (FG) alloys with grain refiners exhibit coarse secondary phases with a reduced number density compared to coarse-grained (CG) alloys without grain refiners. Dynamic recrystallization (DRX) was enhanced at higher compression temperatures and lower strain rates in the CG and FG alloys. Both particle stimulated nucleation (PSN) and continuous dynamic recrystallization (CDRX) are enhanced in the FG alloys, resulting in decreased peak stress values (indicating DRX onset) at 450°C. The peak stress of the FG alloys was higher at 300-400°C than that of the CG alloys because of grain refinement hardening over softening by enhanced DRX.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140717438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147797
Hyo-Seong Kim, M. Kang, Minha Park, Byung Jun Kim, yong-SHin Kim, Tae young Lee, Byoungkoo Kim, Yong-Sik Ahn
In this study, the effect of rolling of 1.25Cr-1Mo-0.5V-0.3C American Iron and Steel Institute 4340 modified steel for highspeed railway brake discs on the microstructure and mechanical properties was investigated. The materials were hot-rolled at 0%, 51%, and 66% reduction ratios, and then analyzed by optical microscopy, scanning electron microscopy, and electron backscattering diffraction (EBSD). needle-shaped ferrite block morphology in bainite varied with the rolling ratio. EBSD analysis reveals dynamic recovery and dynamic recrystallization, affected ferrite block boundaries and dislocation densities during rolling. Mechanical tests showed that hardness, toughness and elongation increase at higher rolling reduction ratio, while strength remained relatively constant. In particular, the impact toughness increased almost twice from the level of 70 J in S1 (0% reduction) to the level of 130 J in S3 (66% reduction). These results showed that the hot rolling can significantly improve the strength and toughness combination of cast brake discs material.
{"title":"Effects of Hot rolling Reduction on Microstructural Evolution and Mechanical Properties of 1.25Cr-1Mo-0.5V-0.3C Steel for High-Speed Rail Brake Discs","authors":"Hyo-Seong Kim, M. Kang, Minha Park, Byung Jun Kim, yong-SHin Kim, Tae young Lee, Byoungkoo Kim, Yong-Sik Ahn","doi":"10.24425/amm.2024.147797","DOIUrl":"https://doi.org/10.24425/amm.2024.147797","url":null,"abstract":"In this study, the effect of rolling of 1.25Cr-1Mo-0.5V-0.3C American Iron and Steel Institute 4340 modified steel for highspeed railway brake discs on the microstructure and mechanical properties was investigated. The materials were hot-rolled at 0%, 51%, and 66% reduction ratios, and then analyzed by optical microscopy, scanning electron microscopy, and electron backscattering diffraction (EBSD). needle-shaped ferrite block morphology in bainite varied with the rolling ratio. EBSD analysis reveals dynamic recovery and dynamic recrystallization, affected ferrite block boundaries and dislocation densities during rolling. Mechanical tests showed that hardness, toughness and elongation increase at higher rolling reduction ratio, while strength remained relatively constant. In particular, the impact toughness increased almost twice from the level of 70 J in S1 (0% reduction) to the level of 130 J in S3 (66% reduction). These results showed that the hot rolling can significantly improve the strength and toughness combination of cast brake discs material.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140720040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147793
Minha Park, Gang Ho Lee, Hyo-Seong Kim, Byoungkoo Kim, Sanghoon Noh, Byung Jun Kim
Inconel 625 is typically used in extreme environments due to excellent mechanical properties such as high strength, corrosion resistance, abrasion resistance and low-temperature toughness. When manufacturing a hot forged flange with a thick and complex shape, the cooling rate varies depending on the location due to the difference in thermal gradient during the cooling process after hot forging. In this study, to evaluate the microstructure and mechanical properties of Inconel 625 according to the cooling rate, we performed heat treatment at 950°C, 1050°C, and 1150°C for 4 hours followed by water cooling. Additionally, temperature data for each location on the flange were obtained using finite element method (FEM) simulation for each heat treatment temperature, revealing a discrepancy in the cooling rate between the surface and the center. Therefore, the correlation between microstructure and mechanical properties according to cooling rate was investigated.
{"title":"Effect of Cooling Rate on Microstructure and Mechanical Properties According to Heat Treatment Temperature of Inconel 625","authors":"Minha Park, Gang Ho Lee, Hyo-Seong Kim, Byoungkoo Kim, Sanghoon Noh, Byung Jun Kim","doi":"10.24425/amm.2024.147793","DOIUrl":"https://doi.org/10.24425/amm.2024.147793","url":null,"abstract":"Inconel 625 is typically used in extreme environments due to excellent mechanical properties such as high strength, corrosion resistance, abrasion resistance and low-temperature toughness. When manufacturing a hot forged flange with a thick and complex shape, the cooling rate varies depending on the location due to the difference in thermal gradient during the cooling process after hot forging. In this study, to evaluate the microstructure and mechanical properties of Inconel 625 according to the cooling rate, we performed heat treatment at 950°C, 1050°C, and 1150°C for 4 hours followed by water cooling. Additionally, temperature data for each location on the flange were obtained using finite element method (FEM) simulation for each heat treatment temperature, revealing a discrepancy in the cooling rate between the surface and the center. Therefore, the correlation between microstructure and mechanical properties according to cooling rate was investigated.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140720445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147794
Minha Park, Gang Ho Lee, Gwangjoo Jang, Hyoung-Chan Kim, Byoungkoo Kim, Byung Jun Kim
API X70 steel requires high strength and toughness for safety in extreme environments like high pressure and low temperature. Submerged Arc Welding (SAW ) is effective for manufacturing thick steel pipes. However, the welding heat input during SAW alters the microstructure and mechanical properties of the heat affected zone (HAZ). Therefore, investigating the correlation between microstructure and mechanical properties in welded X70 pipes is important to address potential degradation of HAZ and weld metal (WM). In this study, post weld heat treatment (PWHT) was performed to improve mechanical properties of HAZ and WM and to reduce residual stress caused by the welding process. We performed PWHT at 640°C for 15 hours and followed by air cooling. After heat treatment, we observed the microstructure through OM and SEM analysis, and investigated the mechanical properties through tensile test, hardness test, and Charpy impact test.
API X70 钢要求具有高强度和韧性，以便在高压和低温等极端环境中确保安全。埋弧焊（SAW）是制造厚钢管的有效方法。然而，埋弧焊时输入的焊接热量会改变热影响区（HAZ）的微观结构和机械性能。因此，研究 X70 焊接钢管的微观结构和机械性能之间的相关性对于解决热影响区和焊接金属 (WM) 的潜在退化问题非常重要。本研究采用焊后热处理 (PWHT) 来改善 HAZ 和 WM 的机械性能，并降低焊接过程中产生的残余应力。我们在 640°C 温度下进行了 15 小时的焊接后热处理，然后进行空气冷却。热处理后，我们通过 OM 和 SEM 分析观察了微观结构，并通过拉伸试验、硬度试验和夏比冲击试验研究了机械性能。
{"title":"The Effects of Post Weld Heat Treatment on Microstructure and Mechanical Properties of API X70 Linepipe using Submerged Arc Welding","authors":"Minha Park, Gang Ho Lee, Gwangjoo Jang, Hyoung-Chan Kim, Byoungkoo Kim, Byung Jun Kim","doi":"10.24425/amm.2024.147794","DOIUrl":"https://doi.org/10.24425/amm.2024.147794","url":null,"abstract":"API X70 steel requires high strength and toughness for safety in extreme environments like high pressure and low temperature. Submerged Arc Welding (SAW ) is effective for manufacturing thick steel pipes. However, the welding heat input during SAW alters the microstructure and mechanical properties of the heat affected zone (HAZ). Therefore, investigating the correlation between microstructure and mechanical properties in welded X70 pipes is important to address potential degradation of HAZ and weld metal (WM). In this study, post weld heat treatment (PWHT) was performed to improve mechanical properties of HAZ and WM and to reduce residual stress caused by the welding process. We performed PWHT at 640°C for 15 hours and followed by air cooling. After heat treatment, we observed the microstructure through OM and SEM analysis, and investigated the mechanical properties through tensile test, hardness test, and Charpy impact test.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140716474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147795
Sang-Hyeon Jo, Seong-Hee Lee
Changes in the microstructure and texture with annealing temperature of a nanostructured complex aluminum alloy fabricated by multi-stack accumulative Roll Bonding (aRB) process using various al alloys are investigated in detail. The aRB process is performed up to 4 cycles without lubrication at room temperature. The specimen fabricated by the aRB is a multi-layer aluminum alloy sheet in which the aa1050, aa5052 and aa6061 al alloys are alternately stacked to each other. The average grain size of the starting material is 140 μm, but after 4 cycles of the ARB process, this is reduced to 150 nm. The complex Al alloy still shows an ultrafine grained microstructure at annealing temperatures up to 250℃, but after annealing at 300℃, it exhibits a heterogeneous structure containing both the ultrafine grains and the coarse grains due to the occurrence of discontinuous recrystallization. The specimens annealed at temperatures above 300 ℃ also show a heterogeneous microstructure even if the heterogeneities of grain size differ from each other. The texture develops abnormally at higher annealing temperatures; the deformation textures are developed as [112]//nD and [111]//nD components, even in the recrystallized specimens. as the annealing temperature increases, the number fraction of the high-angle grain boundaries gradually decreases. The changes in microstructure and texture of the specimens with increase of the annealing temperature are compared to those of the specimens processed by 2-cycle of the aRB.
{"title":"Changes in Microstructure and Texture of a Multi-Stack Accumulative Roll Bonding Processed Complex Aluminum Alloy with Annealing","authors":"Sang-Hyeon Jo, Seong-Hee Lee","doi":"10.24425/amm.2024.147795","DOIUrl":"https://doi.org/10.24425/amm.2024.147795","url":null,"abstract":"Changes in the microstructure and texture with annealing temperature of a nanostructured complex aluminum alloy fabricated by multi-stack accumulative Roll Bonding (aRB) process using various al alloys are investigated in detail. The aRB process is performed up to 4 cycles without lubrication at room temperature. The specimen fabricated by the aRB is a multi-layer aluminum alloy sheet in which the aa1050, aa5052 and aa6061 al alloys are alternately stacked to each other. The average grain size of the starting material is 140 μm, but after 4 cycles of the ARB process, this is reduced to 150 nm. The complex Al alloy still shows an ultrafine grained microstructure at annealing temperatures up to 250℃, but after annealing at 300℃, it exhibits a heterogeneous structure containing both the ultrafine grains and the coarse grains due to the occurrence of discontinuous recrystallization. The specimens annealed at temperatures above 300 ℃ also show a heterogeneous microstructure even if the heterogeneities of grain size differ from each other. The texture develops abnormally at higher annealing temperatures; the deformation textures are developed as [112]//nD and [111]//nD components, even in the recrystallized specimens. as the annealing temperature increases, the number fraction of the high-angle grain boundaries gradually decreases. The changes in microstructure and texture of the specimens with increase of the annealing temperature are compared to those of the specimens processed by 2-cycle of the aRB.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140717003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147796
Woo Cheol Kim, Jong-Hoon Byun
In this study, 316L stainless steel powder was used to produce a porous body that could be used in a specific environment. In contrast to the existing method of producing filters using only spherical powders, we attempted to produce filters using plate- and needle-like powders and evaluated their performance. In the powder preparation step, the shape change of the powder was analyzed by changing the size of the stainless-steel balls used for ball milling. Then, the variations in properties of the sintered porous body caused by the ball size were investigated. As the average ball size decreased, the average particle size of the powder decreased. Moreover, the surface area and pore size of the porous body decreased. Additionally, when balls of different sizes were mixed, the porous body showed a mixture of coarse and fine pores.
{"title":"Fabrication of Porous Sintered Body using Shape-Controled 316l Stainless Steel Powder by High-Energy Ball Milling","authors":"Woo Cheol Kim, Jong-Hoon Byun","doi":"10.24425/amm.2024.147796","DOIUrl":"https://doi.org/10.24425/amm.2024.147796","url":null,"abstract":"In this study, 316L stainless steel powder was used to produce a porous body that could be used in a specific environment. In contrast to the existing method of producing filters using only spherical powders, we attempted to produce filters using plate- and needle-like powders and evaluated their performance. In the powder preparation step, the shape change of the powder was analyzed by changing the size of the stainless-steel balls used for ball milling. Then, the variations in properties of the sintered porous body caused by the ball size were investigated. As the average ball size decreased, the average particle size of the powder decreased. Moreover, the surface area and pore size of the porous body decreased. Additionally, when balls of different sizes were mixed, the porous body showed a mixture of coarse and fine pores.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140718819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147792
Hee Yeon Jeon, Mijeong Park, Seungheon Han, Dong Hoon Lee, Young‐In Lee
Zinc oxide is considered an outstanding photocatalyst candidate, but its low photo-corrosion resistance is a problem to be solved. In the ZnO-ZnS core-shell structure, ZnS acts as a protective layer for the ZnO core, and thus, it can enhance stability and long-term performance. The ZnO-ZnS core-shell structure is synthesized into various nanoscale morphologies with high specific surface areas to improve photocatalytic efficiency. However, they are easily agglomerated and are hard to separate from reaction media. In this study, micro-sized bumpy spheres of ZnO-ZnS core-shell structure were prepared via facile chemical transformation of as-prepared ZnO. After sulfurization of the ZnO template, it was confirmed through SEM, TEM, EDS, and XPS analysis that a uniform ZnS shell layer was formed without significant change in the initial ZnO morphology. The ZnO-ZnS core-shell microsphere has shown superior efficiency and stability in the photocatalytic degradation of Rhodamine B compared with pristine ZnO microspheres
{"title":"Facile Synthesis of Bumpy-Structured ZnO-ZnS Core-Shell Microspheres with Enhanced Photocatalytic Performance","authors":"Hee Yeon Jeon, Mijeong Park, Seungheon Han, Dong Hoon Lee, Young‐In Lee","doi":"10.24425/amm.2024.147792","DOIUrl":"https://doi.org/10.24425/amm.2024.147792","url":null,"abstract":"Zinc oxide is considered an outstanding photocatalyst candidate, but its low photo-corrosion resistance is a problem to be solved. In the ZnO-ZnS core-shell structure, ZnS acts as a protective layer for the ZnO core, and thus, it can enhance stability and long-term performance. The ZnO-ZnS core-shell structure is synthesized into various nanoscale morphologies with high specific surface areas to improve photocatalytic efficiency. However, they are easily agglomerated and are hard to separate from reaction media. In this study, micro-sized bumpy spheres of ZnO-ZnS core-shell structure were prepared via facile chemical transformation of as-prepared ZnO. After sulfurization of the ZnO template, it was confirmed through SEM, TEM, EDS, and XPS analysis that a uniform ZnS shell layer was formed without significant change in the initial ZnO morphology. The ZnO-ZnS core-shell microsphere has shown superior efficiency and stability in the photocatalytic degradation of Rhodamine B compared with pristine ZnO microspheres","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140718906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.24425/amm.2024.147802
Jae-Yun Kim, Sang-Gyu Kim, Byoungchul Hwang
This study explores the hydrogen embrittlement behaviour of two Ni-based superalloys using electrochemical hydrogen charging. Two types of tensile specimens with different geometry for the Haynes 617 and Hastelloy X alloys were electrochemically hydrogen-charged, and then a slow strain rate test was conducted to investigate the hydrogen embrittlement behaviour. Unlike the ASTM standard specimens, two-step dog-bone specimens with a higher surface-area-to-volume ratio showed higher sensitivity to hydrogen embrittlement because hydrogen atoms are distributed mostly on the surface area. On the other hand, the Haynes 617 alloy had a lower hydrogen embrittlement resistance than that of the Hastelloy X alloy due to its relatively large grain size and the presence of precipitates at grain boundaries. The Haynes 617 alloy primarily showed an intergranular fracture mode with cracks from the slip band, whereas the Hastelloy X alloy exhibited a combination of transgranular and intergranular fracture behavior under hydrogen-charged conditions.
本研究利用电化学充氢方法探讨了两种镍基超级合金的氢脆行为。对 Haynes 617 和 Hastelloy X 合金的两种不同几何形状的拉伸试样进行了电化学充氢，然后进行了慢应变速率试验，以研究氢脆行为。与 ASTM 标准试样不同，表面积与体积比更高的两步狗骨试样对氢脆的敏感性更高，因为氢原子主要分布在表面区域。另一方面，Haynes 617 合金的抗氢脆性低于 Hastelloy X 合金，原因是其晶粒尺寸相对较大，且晶界存在析出物。Haynes 617 合金主要表现为晶间断裂模式，裂纹来自滑移带，而 Hastelloy X 合金在充氢条件下则表现为跨晶和晶间断裂行为的结合。
{"title":"Investigation of Hydrogen Embrittlement of Haynes 617 and Hastelloy X Alloys Using Electrochemical Hydrogen Charging","authors":"Jae-Yun Kim, Sang-Gyu Kim, Byoungchul Hwang","doi":"10.24425/amm.2024.147802","DOIUrl":"https://doi.org/10.24425/amm.2024.147802","url":null,"abstract":"This study explores the hydrogen embrittlement behaviour of two Ni-based superalloys using electrochemical hydrogen charging. Two types of tensile specimens with different geometry for the Haynes 617 and Hastelloy X alloys were electrochemically hydrogen-charged, and then a slow strain rate test was conducted to investigate the hydrogen embrittlement behaviour. Unlike the ASTM standard specimens, two-step dog-bone specimens with a higher surface-area-to-volume ratio showed higher sensitivity to hydrogen embrittlement because hydrogen atoms are distributed mostly on the surface area. On the other hand, the Haynes 617 alloy had a lower hydrogen embrittlement resistance than that of the Hastelloy X alloy due to its relatively large grain size and the presence of precipitates at grain boundaries. The Haynes 617 alloy primarily showed an intergranular fracture mode with cracks from the slip band, whereas the Hastelloy X alloy exhibited a combination of transgranular and intergranular fracture behavior under hydrogen-charged conditions.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140719777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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