Pub Date : 2023-01-01DOI: 10.1615/hightempmatproc.2023048119
M. Gridnev, R. Khmyrov
{"title":"MODEL OF HEAT TRANSFER AND CRYSTALLIZATION KINETICS IN THE HEAT-AFFECTED ZONE IN VIT 106 ALLOY IN SELECTIVE LASER MELTING","authors":"M. Gridnev, R. Khmyrov","doi":"10.1615/hightempmatproc.2023048119","DOIUrl":"https://doi.org/10.1615/hightempmatproc.2023048119","url":null,"abstract":"","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81437547","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}
{"title":"Study on vibration and temperature rise characteristics of full ceramic ball bearings under high temperature conditions","authors":"Jian Sun, Renyun Guan, Jinmei Yao, Xin Fang, Zhe Zhang, Guangxiang Zhang","doi":"10.1615/hightempmatproc.2023048090","DOIUrl":"https://doi.org/10.1615/hightempmatproc.2023048090","url":null,"abstract":"","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":"20 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73688742","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}
Ruxing Shi, Xingsheng Yu, Huiqin Chen, Y. Jiao, Juan Chen, Fei Chen, Sizhe He
Abstract As the core foundation of major national equipment, large forgings have a great influence on the national economic construction, the development of national defence equipment and the development of modern cutting-edge science and technology. In the production of large forgings, welding the internal void of forgings is a technical problem that directly affects the quality of large forgings. In view of the phenomenon of void welding in large forgings, the behaviour and mechanism of void welding were deeply studied based on the stretching test and molecular dynamics simulation, combined with a lot of theoretical analysis. The results show that multi-pass stretching deformation is a kind of plastic deformation process which can eliminate void defects. When the forging ratio reaches 2.2, the void can be welded completely and the tensile strength can be restored to the level of the matrix. With the increase of compression deformation, the stress will increase sharply, especially at the grain boundary. In addition, the main void welding mechanism of 30Cr2Ni4MoV steel is the recrystallization and grain growth mechanism. Recrystallization and grain growth are of great significance for promoting the reduction of void volume and realizing metallurgical bonding of the interface.
{"title":"Research on the behaviour and mechanism of void welding based on multiple scales","authors":"Ruxing Shi, Xingsheng Yu, Huiqin Chen, Y. Jiao, Juan Chen, Fei Chen, Sizhe He","doi":"10.1515/htmp-2022-0271","DOIUrl":"https://doi.org/10.1515/htmp-2022-0271","url":null,"abstract":"Abstract As the core foundation of major national equipment, large forgings have a great influence on the national economic construction, the development of national defence equipment and the development of modern cutting-edge science and technology. In the production of large forgings, welding the internal void of forgings is a technical problem that directly affects the quality of large forgings. In view of the phenomenon of void welding in large forgings, the behaviour and mechanism of void welding were deeply studied based on the stretching test and molecular dynamics simulation, combined with a lot of theoretical analysis. The results show that multi-pass stretching deformation is a kind of plastic deformation process which can eliminate void defects. When the forging ratio reaches 2.2, the void can be welded completely and the tensile strength can be restored to the level of the matrix. With the increase of compression deformation, the stress will increase sharply, especially at the grain boundary. In addition, the main void welding mechanism of 30Cr2Ni4MoV steel is the recrystallization and grain growth mechanism. Recrystallization and grain growth are of great significance for promoting the reduction of void volume and realizing metallurgical bonding of the interface.","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41784716","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}
Abstract In this study, hybrid alloys were obtained by casting method with alloy elements and additive such as Si and MoS2, which can be used instead of lead, and compared with Ecobrass and free cutting brass samples used in the market in terms of microstructure, mechanical, and machinability properties. The microstructures of lead-free hybridized brass consists of alpha, beta, and intermetallic compound which were confirmed by the results of X-Ray Diffraction analysis and Scanning Electron Microscopy-Energy Dispersive Spectroscopy. The hardness values of the beta phase in the microstructure are between 180 and 220 Vickers hardness. It has been observed that increasing the amount of beta prime phase also increases the hardness. The machinability of samples was evaluated in terms of surface roughness and chip formation. Chips obtained from samples after machining process were categorized according to ISO 6385-G1 standard. Chip morphologies were examined under optic microscope and scanning electron microscope. The surface roughness value of samples with MoS2 additives was found to be the lowest due to its lubricity effect. Moreover, morphologies, distribution of phases, and intermetallic compounds in the microstructure are found to have a great impact on the machinability and ultimate tensile strength.
{"title":"Investigation of microstructure, machinability, and mechanical properties of new-generation hybrid lead-free brass alloys","authors":"Özbey Semih, Artir Recep","doi":"10.1515/htmp-2022-0263","DOIUrl":"https://doi.org/10.1515/htmp-2022-0263","url":null,"abstract":"Abstract In this study, hybrid alloys were obtained by casting method with alloy elements and additive such as Si and MoS2, which can be used instead of lead, and compared with Ecobrass and free cutting brass samples used in the market in terms of microstructure, mechanical, and machinability properties. The microstructures of lead-free hybridized brass consists of alpha, beta, and intermetallic compound which were confirmed by the results of X-Ray Diffraction analysis and Scanning Electron Microscopy-Energy Dispersive Spectroscopy. The hardness values of the beta phase in the microstructure are between 180 and 220 Vickers hardness. It has been observed that increasing the amount of beta prime phase also increases the hardness. The machinability of samples was evaluated in terms of surface roughness and chip formation. Chips obtained from samples after machining process were categorized according to ISO 6385-G1 standard. Chip morphologies were examined under optic microscope and scanning electron microscope. The surface roughness value of samples with MoS2 additives was found to be the lowest due to its lubricity effect. Moreover, morphologies, distribution of phases, and intermetallic compounds in the microstructure are found to have a great impact on the machinability and ultimate tensile strength.","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42995587","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}
Hiroyuki Fukuyama, Hideo Higashi, M. Adachi, Makoto Ohtsuka
Abstract This study is part of a series of studies aimed at measuring the thermophysical properties of molten phase change material-type metallic thermal energy storage materials near 873 K (600°C). The target material is Al–Si based alloys. First, as a feasibility study, density measurements of the molten state of three Al–Si binary alloys (Al–12.2Si, Al–50Si and Al–90Si in atomic%) were performed. A highly accurate non-contact density measurement method based on the static magnetic field superposition electromagnetic levitation (EML) method was employed as the density measurement method. The validity of this experimental method was confirmed, and density of molten Al–Si base alloys (ADC12 and Al–5.9mass%Si–1.6mass%Fe) were measured as a function of temperature with an expanded uncertainty of 1.2%. In addition, the surface tension of the alloys was measured by the droplet oscillation method using the EML technique. The surface tension was successfully obtained as a function of temperature with expanded uncertainty of 2.3%.
{"title":"Density and surface tension measurements of molten Al–Si based alloys","authors":"Hiroyuki Fukuyama, Hideo Higashi, M. Adachi, Makoto Ohtsuka","doi":"10.1515/htmp-2022-0286","DOIUrl":"https://doi.org/10.1515/htmp-2022-0286","url":null,"abstract":"Abstract This study is part of a series of studies aimed at measuring the thermophysical properties of molten phase change material-type metallic thermal energy storage materials near 873 K (600°C). The target material is Al–Si based alloys. First, as a feasibility study, density measurements of the molten state of three Al–Si binary alloys (Al–12.2Si, Al–50Si and Al–90Si in atomic%) were performed. A highly accurate non-contact density measurement method based on the static magnetic field superposition electromagnetic levitation (EML) method was employed as the density measurement method. The validity of this experimental method was confirmed, and density of molten Al–Si base alloys (ADC12 and Al–5.9mass%Si–1.6mass%Fe) were measured as a function of temperature with an expanded uncertainty of 1.2%. In addition, the surface tension of the alloys was measured by the droplet oscillation method using the EML technique. The surface tension was successfully obtained as a function of temperature with expanded uncertainty of 2.3%.","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43342788","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}
Shixian Zhang, K. Hu, X. Zhao, J. Liang, Yungang Li
Abstract The process of preparing surface composite by molten salt co-deposition is the result of the mass transfer of active particles in molten salt, electrochemical reduction, and solid diffusion. In this study, we prepared Cr–Ni alloy/low-carbon steel surface composites in NaCl, KCl, NaF, Cr2O3, and NiO melt salt system successfully, and analyzed the entire diffusion dynamics process, aiming to find out the limiting links and provide ideas for further improving the preparation efficiency. The results show that chromium and nickel ions are simultaneously reduced on the cathode surface through two and one steps, respectively. And an alloy layer with Fe content of 64.52 wt%, Ni content of 28.96 wt%, and Cr content of 6.52 wt% is formed on the surface of low-carbon steel substrate. The average diffusion coefficients of chromium and nickel atoms in the surface composites are 1.16 × 10−14 and 1.44 × 10−14 m2·s−1. The mass transfer process in molten salt is the limiting link in the whole preparation process.
{"title":"Study on diffusion kinetics of chromium and nickel electrochemical co-deposition in a NaCl–KCl–NaF–Cr2O3–NiO molten salt","authors":"Shixian Zhang, K. Hu, X. Zhao, J. Liang, Yungang Li","doi":"10.1515/htmp-2022-0276","DOIUrl":"https://doi.org/10.1515/htmp-2022-0276","url":null,"abstract":"Abstract The process of preparing surface composite by molten salt co-deposition is the result of the mass transfer of active particles in molten salt, electrochemical reduction, and solid diffusion. In this study, we prepared Cr–Ni alloy/low-carbon steel surface composites in NaCl, KCl, NaF, Cr2O3, and NiO melt salt system successfully, and analyzed the entire diffusion dynamics process, aiming to find out the limiting links and provide ideas for further improving the preparation efficiency. The results show that chromium and nickel ions are simultaneously reduced on the cathode surface through two and one steps, respectively. And an alloy layer with Fe content of 64.52 wt%, Ni content of 28.96 wt%, and Cr content of 6.52 wt% is formed on the surface of low-carbon steel substrate. The average diffusion coefficients of chromium and nickel atoms in the surface composites are 1.16 × 10−14 and 1.44 × 10−14 m2·s−1. The mass transfer process in molten salt is the limiting link in the whole preparation process.","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43459301","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}
Abstract The focus of this study is to regulate the variation in the input parameters of multiple microwave sources in a high-frequency multimode resonant heating system to achieve uniform heating. First, this study deeply expands the theoretical process of frequency change and proposes a frequency-shifting strategy with hot spot alternation to ensure that the temperature difference range of each hot spot does not continuously expand during the heating process. Then, a sequential quadratic programming algorithm is introduced to reconstruct the input power values to improve the heating efficiency according to the different microwave absorption efficiencies of the heated material at different frequencies. Finally, a numerical calculation model for multi-source microwave power-frequency cooperative heating is established based on the finite-element method, and the temperature uniformity index is effectively calculated. Numerical calculations show that the proposed method can improve the uniformity in single-material heating and multi-material heating cases by 56.8–94.3% and 44.4–76.6%, respectively, over that of fixed-frequency heating while achieving improved heating efficiency on the basis of frequency conversion.
{"title":"Temperature uniformity optimization with power-frequency coordinated variation in multi-source microwave based on sequential quadratic programming","authors":"Biao Yang, Zemin Han, Cheng Cheng, Hao Gao, Zhaogang Wu","doi":"10.1515/htmp-2022-0279","DOIUrl":"https://doi.org/10.1515/htmp-2022-0279","url":null,"abstract":"Abstract The focus of this study is to regulate the variation in the input parameters of multiple microwave sources in a high-frequency multimode resonant heating system to achieve uniform heating. First, this study deeply expands the theoretical process of frequency change and proposes a frequency-shifting strategy with hot spot alternation to ensure that the temperature difference range of each hot spot does not continuously expand during the heating process. Then, a sequential quadratic programming algorithm is introduced to reconstruct the input power values to improve the heating efficiency according to the different microwave absorption efficiencies of the heated material at different frequencies. Finally, a numerical calculation model for multi-source microwave power-frequency cooperative heating is established based on the finite-element method, and the temperature uniformity index is effectively calculated. Numerical calculations show that the proposed method can improve the uniformity in single-material heating and multi-material heating cases by 56.8–94.3% and 44.4–76.6%, respectively, over that of fixed-frequency heating while achieving improved heating efficiency on the basis of frequency conversion.","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44017604","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}
Abstract This report investigates the thermal performance of light-emitting diodes (LEDs) using a heat sink structure based on an optimized design and a sprayed cuprous oxide (Cu2O) coating. An orthogonal array of 18 aluminum plates with various heat-dissipated structures was created. The optimal junction temperature of the LED package is determined by using the signal-to-noise ratio (S/N) of the heat-dissipated structure based on Taguchi’s method as well as the heat dissipation coating. According to the analysis of variance, the most important factors that influence the junction temperature can be obtained as the depth of groove, the layout of holes, the layout of LEDs, and the number of Cu block. These significant factors constituted approximately 91.06% of the variation in the experiment. The results show that by optimizing the structure of the LED heat sink based on the heat-dissipated coating, the efficiency of the junction temperature is increased by 23.88%. Also, a gain of 1.30 dB corresponds to a 9.67% reduction in variance, which indicates the improvement through the optimal setting by 1.162 times of variance, showing good reproducibility. Overall, the coating is based on the optimized design of the structure of the heat sink that has good heat transfer capability, which can provide a good solution to the heat-dissipated problem of LED and further give guidance to the future development of LED.
{"title":"Heat management of LED-based Cu2O deposits on the optimal structure of heat sink","authors":"Congrong Wang, Chao Zhang, Qiduan Chen, Hui Lin, Xinting Sun, Jiahao Li, Mingder Jean","doi":"10.1515/htmp-2022-0277","DOIUrl":"https://doi.org/10.1515/htmp-2022-0277","url":null,"abstract":"Abstract This report investigates the thermal performance of light-emitting diodes (LEDs) using a heat sink structure based on an optimized design and a sprayed cuprous oxide (Cu2O) coating. An orthogonal array of 18 aluminum plates with various heat-dissipated structures was created. The optimal junction temperature of the LED package is determined by using the signal-to-noise ratio (S/N) of the heat-dissipated structure based on Taguchi’s method as well as the heat dissipation coating. According to the analysis of variance, the most important factors that influence the junction temperature can be obtained as the depth of groove, the layout of holes, the layout of LEDs, and the number of Cu block. These significant factors constituted approximately 91.06% of the variation in the experiment. The results show that by optimizing the structure of the LED heat sink based on the heat-dissipated coating, the efficiency of the junction temperature is increased by 23.88%. Also, a gain of 1.30 dB corresponds to a 9.67% reduction in variance, which indicates the improvement through the optimal setting by 1.162 times of variance, showing good reproducibility. Overall, the coating is based on the optimized design of the structure of the heat sink that has good heat transfer capability, which can provide a good solution to the heat-dissipated problem of LED and further give guidance to the future development of LED.","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48960890","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}
Abstract The behavior of void surface healing in 316LN steel samples undergoing thermal plasticity deformation was investigated using the Gleeble 1500 thermomechanical simulator. The characterization of the void surface after plastic deformation was analyzed under different deformation temperatures, deformation amounts, and holding time durations. The morphology evolution and microstructure of the void surface healing zone during thermal plasticity deformation and holding time duration stage were analyzed using electron back scatter diffraction imaging. The mechanism of void surface healing under thermal plasticity deformation was investigated. It was found that the degree of void surface healing increases with the degree of deformation and the duration of the holding time. Dynamic recrystallization occurred continuously at the void surface, resulting in a plethora of crystal defects and a substantial amount of energy. These conditions were conducive to atomic diffusion and migration, thereby promoting the healing process of the void surface. Maintaining high temperature after deformation can continue to provide energy for the diffusion and migration of atoms, promotes the growth of recrystallized grains, and gradually heals the void surface.
{"title":"A study of the void surface healing mechanism in 316LN steel","authors":"Mingli Qin, Jiansheng Liu, Jing-dan Li, Xuezhong Zhang","doi":"10.1515/htmp-2022-0282","DOIUrl":"https://doi.org/10.1515/htmp-2022-0282","url":null,"abstract":"Abstract The behavior of void surface healing in 316LN steel samples undergoing thermal plasticity deformation was investigated using the Gleeble 1500 thermomechanical simulator. The characterization of the void surface after plastic deformation was analyzed under different deformation temperatures, deformation amounts, and holding time durations. The morphology evolution and microstructure of the void surface healing zone during thermal plasticity deformation and holding time duration stage were analyzed using electron back scatter diffraction imaging. The mechanism of void surface healing under thermal plasticity deformation was investigated. It was found that the degree of void surface healing increases with the degree of deformation and the duration of the holding time. Dynamic recrystallization occurred continuously at the void surface, resulting in a plethora of crystal defects and a substantial amount of energy. These conditions were conducive to atomic diffusion and migration, thereby promoting the healing process of the void surface. Maintaining high temperature after deformation can continue to provide energy for the diffusion and migration of atoms, promotes the growth of recrystallized grains, and gradually heals the void surface.","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45525743","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}
Daisuke Akiyama, Tomoki Mishima, Y. Okamoto, A. Kirishima
Abstract A powder mixture of UO2 and TiO2 was mechanochemically treated in a planetary ball mill under Ar atmosphere for 1 h using a tungsten carbide vial and balls as the milling medium. Such mechanochemical (MC) treatment reduced the crystallinity of UO2 and TiO2. The mechanochemically treated powder mixture was heated at 700–1,300°C for 6 h under Ar atmosphere and analyzed by X-ray diffraction analysis, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and X-ray absorption fine structure analysis. For comparison, a UO2 and TiO2 mixture without MC treatment was heated and analyzed under the same conditions. UTi2O6 did not form below 1,100°C without MC treatment and only the starting materials were observed. At 1,200 and 1,300°C, a small amount of UTi2O6 and equal amounts of UTi2O6 and UO2 were formed, respectively. The mechanochemically treated sample produced nearly pure UTi2O6 containing small amounts of UO2 impurities when heated above 900°C for 6 h. UTi2O6 was highly crystalline and uniform regardless of the synthesis temperature. It is suggested that the crystallinity of UO2 and TiO2 was reduced and the formation of UTi2O6 was promoted by MC treatment.
{"title":"Dry synthesis of brannerite (UTi2O6) by mechanochemical treatment","authors":"Daisuke Akiyama, Tomoki Mishima, Y. Okamoto, A. Kirishima","doi":"10.1515/htmp-2022-0268","DOIUrl":"https://doi.org/10.1515/htmp-2022-0268","url":null,"abstract":"Abstract A powder mixture of UO2 and TiO2 was mechanochemically treated in a planetary ball mill under Ar atmosphere for 1 h using a tungsten carbide vial and balls as the milling medium. Such mechanochemical (MC) treatment reduced the crystallinity of UO2 and TiO2. The mechanochemically treated powder mixture was heated at 700–1,300°C for 6 h under Ar atmosphere and analyzed by X-ray diffraction analysis, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and X-ray absorption fine structure analysis. For comparison, a UO2 and TiO2 mixture without MC treatment was heated and analyzed under the same conditions. UTi2O6 did not form below 1,100°C without MC treatment and only the starting materials were observed. At 1,200 and 1,300°C, a small amount of UTi2O6 and equal amounts of UTi2O6 and UO2 were formed, respectively. The mechanochemically treated sample produced nearly pure UTi2O6 containing small amounts of UO2 impurities when heated above 900°C for 6 h. UTi2O6 was highly crystalline and uniform regardless of the synthesis temperature. It is suggested that the crystallinity of UO2 and TiO2 was reduced and the formation of UTi2O6 was promoted by MC treatment.","PeriodicalId":12966,"journal":{"name":"High Temperature Materials and Processes","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44052214","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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