The Experts below are selected from a list of 25989 Experts worldwide ranked by ideXlab platform
Hengzhi Fu - One of the best experts on this subject based on the ideXlab platform.
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microstructure and cytotoxicity of al2o3 zro2 eutectic bioceramics with high mechanical properties prepared by laser floating Zone Melting
Ceramics International, 2018Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Hui Yang, Hengzhi FuAbstract:Abstract Developing new generation of strong, tough and stable bioceramics used in dental filed has been highly desired for attaining the clinical requirement of secure and reliable therapy. In this paper, a novel Al2O3-ZrO2 eutectic bioceramics with nearly fully density and extremely aesthetic luster was in-situ prepared by innovative laser floating Zone Melting (LFZM) method. The influence of solidification rates on microstructure evolution, mechanical properties and cytotoxicity was investigated. The eutectic bioceramics displayed a special three dimensional interpenetrating microstructure evolving with increasing the solidification rate. The eutectic colony structure occurred when solidification rate overpassed 8 µm/s, and lamellar spacing was below 1 µm when solidification rate exceeded 30 µm/s. The eutectic bioceramics solidified at 100 µm/s exhibited optimal mechanical properties with an average hardness of 16.53 GPa, fracture toughness of 6.5 MPa m1/2 and flexural strength of 1.37 GPa. The cytotoxicity of Al2O3-ZrO2 eutectic bioceramics was evaluated by MTT methods according to ISO 10993-5 standard. Non-cytotoxic behavior was detected for the eutectic bioceramics, indicating this eutectic bioceramic could be used as promising dental restoration material.
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microstructure tailoring and thermal stability of directionally solidified al 2 o 3 gdalo 3 binary eutectic ceramics by laser floating Zone Melting
Ceramics International, 2018Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Di Zhao, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/GdAlO3 eutectic composite ceramics with low solidification defects are prepared by laser floating Zone Melting to tailor homogeneous microstructure and thermal stability performance under high temperature gradient. At low solidification rate, the solidification microstructure shows periodical growth striations in which coarse colony microstructure and homogeneous ‘Chinese script’ irregular eutectic structure are coexisted. The growth striation interval L and solidification rate V follow the relationship of L/V = (238.8 ± 2.4) s. By further optimizing laser processing parameters, the eutectic spacing is greatly refined to submicron scale and microstructure oscillation is eliminated at high solidification rates, and fully regular lamellar/rod eutectic structures are obtained by faceted eutectic transition. The rod-like eutectic spacing (λ) and solidification rate (V) follow the linear relationship of λ·V1/2 = 6.21 µm3/2 s−1/2. Furthermore, the as-solidified eutectic composite even with fine eutectic structure exhibits excellent thermal stability after heat exposure at 1500 °C for 250 h.
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processing microstructure and performance of al 2 o 3 er 3 al 5 o 12 zro 2 ternary eutectic ceramics prepared by laser floating Zone Melting with ultra high temperature gradient
Ceramics International, 2017Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Ze Lu, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/Er3Al5O12(EAG)/ZrO2 ternary eutectic/off-eutectic composite ceramics with high density, homogeneous microstructures, well-oriented growth have been prepared by laser floating Zone Melting at different solidification rates from 4 to 400 µm/s. Uniform and stable Melting Zone is obtained by optimizing temperature field distribution to keep continuous and stable eutectic growth and prevent from cracks and defects. The as-solidified composite ceramic exhibits complexly irregular eutectic structure, in which the eutectic spacing is rapidly refined but dotted ZrO2 number inside Al2O3 phase is decreased as increasing the solidification rate. The formation mechanism of ZrO2 distributed inside Al2O3 matrix is revealed by examining the depression of solid/liquid interface. Furthermore, after heat exposure 1500 °C for 200 h, the eutectic microstructure only shows tiny coarsening, which indicates it has excellent microstructural stability. As increasing the ZrO2 content, the fracture toughness can be improved up to 3.5 MPa m1/2 at 20.6 mol% ZrO2.
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microstructures and mechanical properties of directionally solidified al2o3 gdalo3 eutectic ceramic by laser floating Zone Melting with high temperature gradient
Journal of The European Ceramic Society, 2017Co-Authors: Haijun Su, Jun Zhang, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/GdAlO3 eutectic ceramic rods with high densities and low solidification defects are prepared by laser floating Zone Melting at solidification rate from 2 to 200 μm/s. The microstructure evolution, eutectic growth behavior and mechanical properties are investigated. At low solidification rates (
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directional solidification and growth characteristics of al2o3 er3al5o12 zro2 ternary eutectic ceramic by laser floating Zone Melting
Journal of Materials Science, 2017Co-Authors: Haijun Su, Jun Zhang, Jun Chen, Hengzhi FuAbstract:Directionally solidified Al2O3/Er3Al5O12/ZrO2 ternary eutectic ceramic in situ composite rods with length of 110 mm have been fabricated by laser floating Zone Melting. The microstructural characteristics of steady growth Zone, initial growth Zone and solid/liquid interface are investigated under high temperature gradient. In the steady growth Zone, the eutectic spacing (λ) is rapidly decreased as increasing the growth rate (V), and the corresponding relationship between growth rate and eutectic spacing is determined to be λ = 11.14 × V−1/2. The temperature gradient has been measured to be about 5.3 × 103 K/cm. In the initial growth Zone, the Melting process and temperature distribution are recorded by infrared thermal imager, and several unstable complex microstructures are observed. In the quenched Zone, the regular eutectics with minimum eutectic spacing of 200 nm are obtained. Moreover, the solid/liquid interface during solidification shows convex interface morphology and the interface height is gradually decreased as increasing the growth rate. The eutectic growth behaviors at the center and edge of the as-grown rod are compared and discussed.
Haijun Su - One of the best experts on this subject based on the ideXlab platform.
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directional solidification of fe al ta eutectic by electron beam floating Zone Melting
Journal of Alloys and Compounds, 2019Co-Authors: Songyuan Wang, Haijun SuAbstract:Abstract Fe-Al-Ta eutectic composites have been paid more attentions for high temperature application. Nevertheless, still there is a lack of research on microstructural characteristics and crystal growth mechanism of this eutectic obtained by high temperature gradient directional solidification technique. As such, Fe-Al-Ta eutectic composites were prepared by high temperature gradient electron beam floating Zone Melting technique in the present paper. Microstructures, solid/liquid interface morphologies and preferential orientations of the Fe-Al-Ta eutectic composites at different solidification rates were studied. Moreover, effect of interface perturbation wavelength on stability of the solid/liquid interface was calculated according to M-S theory and Kurz-Fisher model, respectively. These are consistent with the experimental results well.
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microstructure and cytotoxicity of al2o3 zro2 eutectic bioceramics with high mechanical properties prepared by laser floating Zone Melting
Ceramics International, 2018Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Hui Yang, Hengzhi FuAbstract:Abstract Developing new generation of strong, tough and stable bioceramics used in dental filed has been highly desired for attaining the clinical requirement of secure and reliable therapy. In this paper, a novel Al2O3-ZrO2 eutectic bioceramics with nearly fully density and extremely aesthetic luster was in-situ prepared by innovative laser floating Zone Melting (LFZM) method. The influence of solidification rates on microstructure evolution, mechanical properties and cytotoxicity was investigated. The eutectic bioceramics displayed a special three dimensional interpenetrating microstructure evolving with increasing the solidification rate. The eutectic colony structure occurred when solidification rate overpassed 8 µm/s, and lamellar spacing was below 1 µm when solidification rate exceeded 30 µm/s. The eutectic bioceramics solidified at 100 µm/s exhibited optimal mechanical properties with an average hardness of 16.53 GPa, fracture toughness of 6.5 MPa m1/2 and flexural strength of 1.37 GPa. The cytotoxicity of Al2O3-ZrO2 eutectic bioceramics was evaluated by MTT methods according to ISO 10993-5 standard. Non-cytotoxic behavior was detected for the eutectic bioceramics, indicating this eutectic bioceramic could be used as promising dental restoration material.
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microstructure tailoring and thermal stability of directionally solidified al 2 o 3 gdalo 3 binary eutectic ceramics by laser floating Zone Melting
Ceramics International, 2018Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Di Zhao, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/GdAlO3 eutectic composite ceramics with low solidification defects are prepared by laser floating Zone Melting to tailor homogeneous microstructure and thermal stability performance under high temperature gradient. At low solidification rate, the solidification microstructure shows periodical growth striations in which coarse colony microstructure and homogeneous ‘Chinese script’ irregular eutectic structure are coexisted. The growth striation interval L and solidification rate V follow the relationship of L/V = (238.8 ± 2.4) s. By further optimizing laser processing parameters, the eutectic spacing is greatly refined to submicron scale and microstructure oscillation is eliminated at high solidification rates, and fully regular lamellar/rod eutectic structures are obtained by faceted eutectic transition. The rod-like eutectic spacing (λ) and solidification rate (V) follow the linear relationship of λ·V1/2 = 6.21 µm3/2 s−1/2. Furthermore, the as-solidified eutectic composite even with fine eutectic structure exhibits excellent thermal stability after heat exposure at 1500 °C for 250 h.
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processing microstructure and performance of al 2 o 3 er 3 al 5 o 12 zro 2 ternary eutectic ceramics prepared by laser floating Zone Melting with ultra high temperature gradient
Ceramics International, 2017Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Ze Lu, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/Er3Al5O12(EAG)/ZrO2 ternary eutectic/off-eutectic composite ceramics with high density, homogeneous microstructures, well-oriented growth have been prepared by laser floating Zone Melting at different solidification rates from 4 to 400 µm/s. Uniform and stable Melting Zone is obtained by optimizing temperature field distribution to keep continuous and stable eutectic growth and prevent from cracks and defects. The as-solidified composite ceramic exhibits complexly irregular eutectic structure, in which the eutectic spacing is rapidly refined but dotted ZrO2 number inside Al2O3 phase is decreased as increasing the solidification rate. The formation mechanism of ZrO2 distributed inside Al2O3 matrix is revealed by examining the depression of solid/liquid interface. Furthermore, after heat exposure 1500 °C for 200 h, the eutectic microstructure only shows tiny coarsening, which indicates it has excellent microstructural stability. As increasing the ZrO2 content, the fracture toughness can be improved up to 3.5 MPa m1/2 at 20.6 mol% ZrO2.
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microstructures and mechanical properties of directionally solidified al2o3 gdalo3 eutectic ceramic by laser floating Zone Melting with high temperature gradient
Journal of The European Ceramic Society, 2017Co-Authors: Haijun Su, Jun Zhang, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/GdAlO3 eutectic ceramic rods with high densities and low solidification defects are prepared by laser floating Zone Melting at solidification rate from 2 to 200 μm/s. The microstructure evolution, eutectic growth behavior and mechanical properties are investigated. At low solidification rates (
Jun Zhang - One of the best experts on this subject based on the ideXlab platform.
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microstructure and cytotoxicity of al2o3 zro2 eutectic bioceramics with high mechanical properties prepared by laser floating Zone Melting
Ceramics International, 2018Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Hui Yang, Hengzhi FuAbstract:Abstract Developing new generation of strong, tough and stable bioceramics used in dental filed has been highly desired for attaining the clinical requirement of secure and reliable therapy. In this paper, a novel Al2O3-ZrO2 eutectic bioceramics with nearly fully density and extremely aesthetic luster was in-situ prepared by innovative laser floating Zone Melting (LFZM) method. The influence of solidification rates on microstructure evolution, mechanical properties and cytotoxicity was investigated. The eutectic bioceramics displayed a special three dimensional interpenetrating microstructure evolving with increasing the solidification rate. The eutectic colony structure occurred when solidification rate overpassed 8 µm/s, and lamellar spacing was below 1 µm when solidification rate exceeded 30 µm/s. The eutectic bioceramics solidified at 100 µm/s exhibited optimal mechanical properties with an average hardness of 16.53 GPa, fracture toughness of 6.5 MPa m1/2 and flexural strength of 1.37 GPa. The cytotoxicity of Al2O3-ZrO2 eutectic bioceramics was evaluated by MTT methods according to ISO 10993-5 standard. Non-cytotoxic behavior was detected for the eutectic bioceramics, indicating this eutectic bioceramic could be used as promising dental restoration material.
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microstructure tailoring and thermal stability of directionally solidified al 2 o 3 gdalo 3 binary eutectic ceramics by laser floating Zone Melting
Ceramics International, 2018Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Di Zhao, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/GdAlO3 eutectic composite ceramics with low solidification defects are prepared by laser floating Zone Melting to tailor homogeneous microstructure and thermal stability performance under high temperature gradient. At low solidification rate, the solidification microstructure shows periodical growth striations in which coarse colony microstructure and homogeneous ‘Chinese script’ irregular eutectic structure are coexisted. The growth striation interval L and solidification rate V follow the relationship of L/V = (238.8 ± 2.4) s. By further optimizing laser processing parameters, the eutectic spacing is greatly refined to submicron scale and microstructure oscillation is eliminated at high solidification rates, and fully regular lamellar/rod eutectic structures are obtained by faceted eutectic transition. The rod-like eutectic spacing (λ) and solidification rate (V) follow the linear relationship of λ·V1/2 = 6.21 µm3/2 s−1/2. Furthermore, the as-solidified eutectic composite even with fine eutectic structure exhibits excellent thermal stability after heat exposure at 1500 °C for 250 h.
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processing microstructure and performance of al 2 o 3 er 3 al 5 o 12 zro 2 ternary eutectic ceramics prepared by laser floating Zone Melting with ultra high temperature gradient
Ceramics International, 2017Co-Authors: Haijun Su, Enyuan Wang, Jun Zhang, Ze Lu, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/Er3Al5O12(EAG)/ZrO2 ternary eutectic/off-eutectic composite ceramics with high density, homogeneous microstructures, well-oriented growth have been prepared by laser floating Zone Melting at different solidification rates from 4 to 400 µm/s. Uniform and stable Melting Zone is obtained by optimizing temperature field distribution to keep continuous and stable eutectic growth and prevent from cracks and defects. The as-solidified composite ceramic exhibits complexly irregular eutectic structure, in which the eutectic spacing is rapidly refined but dotted ZrO2 number inside Al2O3 phase is decreased as increasing the solidification rate. The formation mechanism of ZrO2 distributed inside Al2O3 matrix is revealed by examining the depression of solid/liquid interface. Furthermore, after heat exposure 1500 °C for 200 h, the eutectic microstructure only shows tiny coarsening, which indicates it has excellent microstructural stability. As increasing the ZrO2 content, the fracture toughness can be improved up to 3.5 MPa m1/2 at 20.6 mol% ZrO2.
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microstructures and mechanical properties of directionally solidified al2o3 gdalo3 eutectic ceramic by laser floating Zone Melting with high temperature gradient
Journal of The European Ceramic Society, 2017Co-Authors: Haijun Su, Jun Zhang, Hengzhi FuAbstract:Abstract Directionally solidified Al2O3/GdAlO3 eutectic ceramic rods with high densities and low solidification defects are prepared by laser floating Zone Melting at solidification rate from 2 to 200 μm/s. The microstructure evolution, eutectic growth behavior and mechanical properties are investigated. At low solidification rates (
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directional solidification and growth characteristics of al2o3 er3al5o12 zro2 ternary eutectic ceramic by laser floating Zone Melting
Journal of Materials Science, 2017Co-Authors: Haijun Su, Jun Zhang, Jun Chen, Hengzhi FuAbstract:Directionally solidified Al2O3/Er3Al5O12/ZrO2 ternary eutectic ceramic in situ composite rods with length of 110 mm have been fabricated by laser floating Zone Melting. The microstructural characteristics of steady growth Zone, initial growth Zone and solid/liquid interface are investigated under high temperature gradient. In the steady growth Zone, the eutectic spacing (λ) is rapidly decreased as increasing the growth rate (V), and the corresponding relationship between growth rate and eutectic spacing is determined to be λ = 11.14 × V−1/2. The temperature gradient has been measured to be about 5.3 × 103 K/cm. In the initial growth Zone, the Melting process and temperature distribution are recorded by infrared thermal imager, and several unstable complex microstructures are observed. In the quenched Zone, the regular eutectics with minimum eutectic spacing of 200 nm are obtained. Moreover, the solid/liquid interface during solidification shows convex interface morphology and the interface height is gradually decreased as increasing the growth rate. The eutectic growth behaviors at the center and edge of the as-grown rod are compared and discussed.
Lin Liu - One of the best experts on this subject based on the ideXlab platform.
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directional solidification and growth characteristics of al2o3 er3al5o12 zro2 ternary eutectic ceramic by laser floating Zone Melting
Journal of Materials Science, 2017Co-Authors: Qun Ren, Jun Zhang, Jun Chen, Yewei Cao, Lin LiuAbstract:Directionally solidified Al2O3/Er3Al5O12/ZrO2 ternary eutectic ceramic in situ composite rods with length of 110 mm have been fabricated by laser floating Zone Melting. The microstructural characteristics of steady growth Zone, initial growth Zone and solid/liquid interface are investigated under high temperature gradient. In the steady growth Zone, the eutectic spacing (λ) is rapidly decreased as increasing the growth rate (V), and the corresponding relationship between growth rate and eutectic spacing is determined to be λ = 11.14 × V −1/2. The temperature gradient has been measured to be about 5.3 × 103 K/cm. In the initial growth Zone, the Melting process and temperature distribution are recorded by infrared thermal imager, and several unstable complex microstructures are observed. In the quenched Zone, the regular eutectics with minimum eutectic spacing of 200 nm are obtained. Moreover, the solid/liquid interface during solidification shows convex interface morphology and the interface height is gradually decreased as increasing the growth rate. The eutectic growth behaviors at the center and edge of the as-grown rod are compared and discussed.
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rapid eutectic growth of al2o3 er3al5o12 nanocomposite prepared by a new method melt falling drop quenching
Scripta Materialia, 2016Co-Authors: Qun Ren, Jun Zhang, Bin Yao, Lin LiuAbstract:Abstract A novel melt falling-drop quenching method with rapid cooling rate is carried out to prepare the Al 2 O 3 /Er 3 Al 5 O 12 nanoeutectic ceramic based on laser floating Zone Melting. The regular eutectic structure with minimum interphase spacing of 30 nm is obtained, which is much smaller than previous reports. The continuous transition of irregular eutectic to regular eutectic and to amorphous structure is found under rapid solidification, and the instability mechanism of eutectic growth is discussed. On the basis, the corresponding eutectic growth rate during rapid solidification, which is calculated by Jackson-Hunt model and Trivedi-Magnin-Kurz model, is between 8.65 μm/s ~ 5.32 × 10 4 μm/s.
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solid liquid interface and growth rate range of al2o3 based eutectic in situ composites grown by laser floating Zone Melting
Journal of Alloys and Compounds, 2016Co-Authors: Qun Ren, Jun Zhang, Lin Liu, Taiwen Huang, Bin Yao, Min Guo, Wenchao YangAbstract:Abstract Directionally solidified Al 2 O 3 /Er 3 Al 5 O 12 (EAG) eutectic in situ composites are prepared by laser floating Zone Melting (LFZM) to investigate the solid–liquid interface characteristic and growth rate range under non-equilibrium solidification conditions. The solid–liquid ( S–L ) interface is in situ obtained by rapidly quenching, and its microstructure morphology and primary phase based on different eutectic compositions are analyzed. In stable growth Zone, the composite presents typically “Chinese script” (CS) irregular eutectic structure consisting of interpenetrated Al 2 O 3 and EAG phases, but in quenched region the regular eutectic lamellae and CS structure are coexisted. Primary Al 2 O 3 phase in hypoeutectic composition is found both in S–L interface front and quenched region. Different from the stable growth Zone, in quenched region as the solidification rate increases, the eutectic lamellae spacing does not show obvious decrease. The minimum eutectic lamellae spacing is refined to about 200 nm when the solidification rate is increased up to 100 μm/s. On the basis, according to the Jackson-Hunt (J-H) model, the maximum solidification rate in quenched region is calculated to be smaller than 1.26 × 10 3 μm/s, and the undercooling degree is 4.15 K.
Qun Ren - One of the best experts on this subject based on the ideXlab platform.
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directional solidification and growth characteristics of al2o3 er3al5o12 zro2 ternary eutectic ceramic by laser floating Zone Melting
Journal of Materials Science, 2017Co-Authors: Qun Ren, Jun Zhang, Jun Chen, Yewei Cao, Lin LiuAbstract:Directionally solidified Al2O3/Er3Al5O12/ZrO2 ternary eutectic ceramic in situ composite rods with length of 110 mm have been fabricated by laser floating Zone Melting. The microstructural characteristics of steady growth Zone, initial growth Zone and solid/liquid interface are investigated under high temperature gradient. In the steady growth Zone, the eutectic spacing (λ) is rapidly decreased as increasing the growth rate (V), and the corresponding relationship between growth rate and eutectic spacing is determined to be λ = 11.14 × V −1/2. The temperature gradient has been measured to be about 5.3 × 103 K/cm. In the initial growth Zone, the Melting process and temperature distribution are recorded by infrared thermal imager, and several unstable complex microstructures are observed. In the quenched Zone, the regular eutectics with minimum eutectic spacing of 200 nm are obtained. Moreover, the solid/liquid interface during solidification shows convex interface morphology and the interface height is gradually decreased as increasing the growth rate. The eutectic growth behaviors at the center and edge of the as-grown rod are compared and discussed.
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rapid eutectic growth of al2o3 er3al5o12 nanocomposite prepared by a new method melt falling drop quenching
Scripta Materialia, 2016Co-Authors: Qun Ren, Jun Zhang, Bin Yao, Lin LiuAbstract:Abstract A novel melt falling-drop quenching method with rapid cooling rate is carried out to prepare the Al 2 O 3 /Er 3 Al 5 O 12 nanoeutectic ceramic based on laser floating Zone Melting. The regular eutectic structure with minimum interphase spacing of 30 nm is obtained, which is much smaller than previous reports. The continuous transition of irregular eutectic to regular eutectic and to amorphous structure is found under rapid solidification, and the instability mechanism of eutectic growth is discussed. On the basis, the corresponding eutectic growth rate during rapid solidification, which is calculated by Jackson-Hunt model and Trivedi-Magnin-Kurz model, is between 8.65 μm/s ~ 5.32 × 10 4 μm/s.
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solid liquid interface and growth rate range of al2o3 based eutectic in situ composites grown by laser floating Zone Melting
Journal of Alloys and Compounds, 2016Co-Authors: Qun Ren, Jun Zhang, Lin Liu, Taiwen Huang, Bin Yao, Min Guo, Wenchao YangAbstract:Abstract Directionally solidified Al 2 O 3 /Er 3 Al 5 O 12 (EAG) eutectic in situ composites are prepared by laser floating Zone Melting (LFZM) to investigate the solid–liquid interface characteristic and growth rate range under non-equilibrium solidification conditions. The solid–liquid ( S–L ) interface is in situ obtained by rapidly quenching, and its microstructure morphology and primary phase based on different eutectic compositions are analyzed. In stable growth Zone, the composite presents typically “Chinese script” (CS) irregular eutectic structure consisting of interpenetrated Al 2 O 3 and EAG phases, but in quenched region the regular eutectic lamellae and CS structure are coexisted. Primary Al 2 O 3 phase in hypoeutectic composition is found both in S–L interface front and quenched region. Different from the stable growth Zone, in quenched region as the solidification rate increases, the eutectic lamellae spacing does not show obvious decrease. The minimum eutectic lamellae spacing is refined to about 200 nm when the solidification rate is increased up to 100 μm/s. On the basis, according to the Jackson-Hunt (J-H) model, the maximum solidification rate in quenched region is calculated to be smaller than 1.26 × 10 3 μm/s, and the undercooling degree is 4.15 K.
