The Experts below are selected from a list of 3921 Experts worldwide ranked by ideXlab platform
Jun Zhang - One of the best experts on this subject based on the ideXlab platform.
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Theoretical prediction and experimental comparison for eutectic growth of Al2O3/GdAlO3 faceted eutectics
Journal of the European Ceramic Society, 2019Co-Authors: Jun Zhang, Guangrao Fan, Qun Ren, Zhonglin Shen, Min Guo, Lin LiuAbstract:Abstract Ultra-fine Al2O3/GdAlO3 eutectics with eutectic spacing of 193 ± 20 nm are directionally solidified by laser floating zone melting process. When the solidification rate increases from 2 μm/s to 400 μm/s, the morphology transition from “Chinese Script” irregular eutectic to rod-like regular eutectic is found. To predict the growth behaviour of Al2O3/GdAlO3 eutectic, the solute diffusion coefficient D L , which exhibits significant influence on eutectic growth, is determined to be 6 × 10−10 m2/s. Then, the eutectic microstructures as a function of solidification rate are well predicted by modified Magnin-Kurz model and Jackson-Hunt model, both for “Chinese Script” irregular eutectic and rod-like regular eutectic, respectively.
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microstructure transformation from irregular eutectic to complex regular eutectic in directionally solidified al2o3 gdalo3 zro2 ceramics by laser floating zone melting
Journal of The European Ceramic Society, 2016Co-Authors: Jun Zhang, Haijun Su, Hengzhi FuAbstract:Abstract Directionally solidified Al 2 O 3 /GdAlO 3 (GAP)/ZrO 2 (GdSZ) ternary eutectic ceramics have been grown by laser floating zone melting. The microstructure evolution rule is investigated as a function of growth rate. The as-solidified samples present high density (>99%), smooth surface and high diameter stability free of pores and cracks. Increasing the growth rate from 4 to 100 μm/s, the microstructures undergo a transformation from “Chinese Script” irregular eutectic pattern to eutectic colony and to complex regular eutectic patterns (lamellae or rods). The average interphase spacing of the “Chinese Script” microstructure presents an inverse square relationship according to λ = 10.46 × ν −1/2 , where the average interphase spacing λ has the dimension of μm and growth rate ν is in μm/s. While the interphase spacing of the complex regular microstructure is finer. The mechanisms of the microstructure evolution and the effects of ZrO 2 phase on the morphology and domain size of microstructure are discussed in detail.
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Microstructure transformation from irregular eutectic to complex regular eutectic in directionally solidified Al2O3/GdAlO3/ZrO2 ceramics by laser floating zone melting
Journal of the European Ceramic Society, 2016Co-Authors: Jun Zhang, Qun Ren, Bin Yao, Lin LiuAbstract:Abstract Directionally solidified Al 2 O 3 /GdAlO 3 (GAP)/ZrO 2 (GdSZ) ternary eutectic ceramics have been grown by laser floating zone melting. The microstructure evolution rule is investigated as a function of growth rate. The as-solidified samples present high density (>99%), smooth surface and high diameter stability free of pores and cracks. Increasing the growth rate from 4 to 100 μm/s, the microstructures undergo a transformation from “Chinese Script” irregular eutectic pattern to eutectic colony and to complex regular eutectic patterns (lamellae or rods). The average interphase spacing of the “Chinese Script” microstructure presents an inverse square relationship according to λ = 10.46 × ν −1/2 , where the average interphase spacing λ has the dimension of μm and growth rate ν is in μm/s. While the interphase spacing of the complex regular microstructure is finer. The mechanisms of the microstructure evolution and the effects of ZrO 2 phase on the morphology and domain size of microstructure are discussed in detail.
Lin Liu - One of the best experts on this subject based on the ideXlab platform.
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Theoretical prediction and experimental comparison for eutectic growth of Al2O3/GdAlO3 faceted eutectics
Journal of the European Ceramic Society, 2019Co-Authors: Jun Zhang, Guangrao Fan, Qun Ren, Zhonglin Shen, Min Guo, Lin LiuAbstract:Abstract Ultra-fine Al2O3/GdAlO3 eutectics with eutectic spacing of 193 ± 20 nm are directionally solidified by laser floating zone melting process. When the solidification rate increases from 2 μm/s to 400 μm/s, the morphology transition from “Chinese Script” irregular eutectic to rod-like regular eutectic is found. To predict the growth behaviour of Al2O3/GdAlO3 eutectic, the solute diffusion coefficient D L , which exhibits significant influence on eutectic growth, is determined to be 6 × 10−10 m2/s. Then, the eutectic microstructures as a function of solidification rate are well predicted by modified Magnin-Kurz model and Jackson-Hunt model, both for “Chinese Script” irregular eutectic and rod-like regular eutectic, respectively.
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Microstructure transformation from irregular eutectic to complex regular eutectic in directionally solidified Al2O3/GdAlO3/ZrO2 ceramics by laser floating zone melting
Journal of the European Ceramic Society, 2016Co-Authors: Jun Zhang, Qun Ren, Bin Yao, Lin LiuAbstract:Abstract Directionally solidified Al 2 O 3 /GdAlO 3 (GAP)/ZrO 2 (GdSZ) ternary eutectic ceramics have been grown by laser floating zone melting. The microstructure evolution rule is investigated as a function of growth rate. The as-solidified samples present high density (>99%), smooth surface and high diameter stability free of pores and cracks. Increasing the growth rate from 4 to 100 μm/s, the microstructures undergo a transformation from “Chinese Script” irregular eutectic pattern to eutectic colony and to complex regular eutectic patterns (lamellae or rods). The average interphase spacing of the “Chinese Script” microstructure presents an inverse square relationship according to λ = 10.46 × ν −1/2 , where the average interphase spacing λ has the dimension of μm and growth rate ν is in μm/s. While the interphase spacing of the complex regular microstructure is finer. The mechanisms of the microstructure evolution and the effects of ZrO 2 phase on the morphology and domain size of microstructure are discussed in detail.
Datong Zhang - One of the best experts on this subject based on the ideXlab platform.
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The effect of Si addition on the microstructure and tensile properties of casting Al-5.0Cu-0.6Mn-1.2Fe alloys
arXiv: Materials Science, 2017Co-Authors: Weiwen Zhang, Yuliang Zhao, Datong Zhang, Zong-qiang Luo, Chao YangAbstract:In this work, we studied the effect of Si on the microstructure and tensile properties of the as-cast Al-5.0Cu-0.6Mn-1.2Fe alloys which were produced by casting with or without applied pressure. The results show that the addition of Si can significantly influence the microstructure and tensile properties of the alloys. For the alloys produced without pressure, the addition of Si can promote the formation of Chinese Script {\alpha}-Fe, suppress the precipitation of plate-like Al3(FeMn) and Chinese Script Al6(FeMn) and increase the volume percent of porosity, resulting in a remarkable decrease in the ultimate tensile strength (UTS) and yield strength (YS). For the alloys produced with a pressure of 75 MPa, the addition of Si can also promote the formation of fine Chinese Script {\alpha}-Fe and high number density Al2Cu ({\theta}) phases, resulting in a slight increase in UTS and YS. The strength and elongation of the alloys increases with increasing applied pressure at the same Si level, which are attributed to the elimination of porosity, grain refinement strengthening and solid-solution strengthening. The alloy with addition of 1.1 % Si produced under the applied pressure of 75 MPa shows the best tensile properties, where the UTS, YS and elongation is 237 MPa, 140 MPa and 9.8%, respectively.
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Microstructures and mechanical properties of squeeze cast Al–5.0Cu–0.6Mn alloys with different Fe content
Materials & Design (1980-2015), 2013Co-Authors: Weiwen Zhang, Bo Lin, Datong ZhangAbstract:Abstract The microstructures and mechanical properties of gravity die cast and squeeze cast Al–5.0 wt% Cu–0.6 wt% Mn alloys with different Fe content have been studied using tensile test, optical microscope, scanning electron microscope, electron probe micro-analyzer and image analysis. The results show that four kinds of Fe-rich intermetallics may present in the final microstructures of the alloys: Chinese Script α-Fe (Al15(FeMn)3(CuSi)2) and Al6(FeMn), needle-like β-Fe(Al7Cu2Fe) and Al3(FeMn) when the Fe content increases from 0.1 wt% to 1.5 wt%. In the gravity die cast alloy with 0.5 wt% Fe, the Chinese Script α-Fe presents as the main Fe-rich intermetallics, and a few needle-like β-Fe also exist. When the Fe content increases to 1.0 wt%, the main Fe-rich intermetallics change to needle-like Al3(FeMn) and Chinese-Script Al6(FeMn). The needle-like β-Fe disappears when the Fe content is 0.5 wt% in the squeeze cast alloy with an applied pressure of 75 MPa. Furthermore, the secondary dendritic arm spacing of α(Al), the percentage of porosity and the volume fraction of the second intermetallics decrease distinctly in the squeeze cast alloy compared to the gravity die cast alloy. There is a peak value of ultimate strength and yield strength for the alloy with 0.5 wt% Fe. The elongations of the alloys decrease gradually with increasing Fe content and the elongation of the squeeze cast alloys is two times more than that of the gravity die cast alloys.
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Microstructures and mechanical properties of heat-treated Al–5.0Cu–0.5Fe squeeze cast alloys with different Mn/Fe ratio
Materials Science and Engineering: A, 2013Co-Authors: Weiwen Zhang, Bo Lin, Jianlei Fan, Datong ZhangAbstract:Abstract The Al–5.0 wt% Cu–0.5 wt% Fe alloys with different Mn/Fe ratio were prepared by squeeze casting. Various test techniques, including tensile test, image analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM) were used to examine the microstructures and mechanical properties of the alloys in T5 heat-treated condition. The results show that the β-Fe (Al7Cu2Fe) is stable and its needle-like morphology is maintained after T5 heat treatment. However, the Chinese Script AlmFe, α-Fe or Al6(FeMn) partially transform to a new Chinese Script Cu-rich α(CuFe) (Al7Cu2Fe or Al7Cu2(FeMn)), which is harmful to the mechanical properties of the alloys due to the decrease of the Cu content in α(Al) matrix. The optimal Mn/Fe ratio is determined by the morphology of Fe-rich intermetallics, volume fraction of θ′ and T (Al20Cu2Mn3), size of α(Al) dendrite and porosity. Excessive Mn/Fe ratio will deteriorate the mechanical properties of the alloys due to the increase of the total amount of porosity and the Fe-rich intermetallics. When the Mn/Fe ratio is 1.6 and 1.2 for the applied pressure of 0 MPa and 75 MPa, respectively, the needle-like β-Fe phase is completely converted to the Chinese Script Fe-rich intermetallics. The ultimate tensile strength, yield strength and elongation of the T5 heat-treated alloy with the Mn/Fe ratio of 1.2 and applied pressure of 75 MPa reach 395 MPa, 335 MPa and 14%, respectively.
Weiwen Zhang - One of the best experts on this subject based on the ideXlab platform.
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The effect of Si addition on the microstructure and tensile properties of casting Al-5.0Cu-0.6Mn-1.2Fe alloys
arXiv: Materials Science, 2017Co-Authors: Weiwen Zhang, Yuliang Zhao, Datong Zhang, Zong-qiang Luo, Chao YangAbstract:In this work, we studied the effect of Si on the microstructure and tensile properties of the as-cast Al-5.0Cu-0.6Mn-1.2Fe alloys which were produced by casting with or without applied pressure. The results show that the addition of Si can significantly influence the microstructure and tensile properties of the alloys. For the alloys produced without pressure, the addition of Si can promote the formation of Chinese Script {\alpha}-Fe, suppress the precipitation of plate-like Al3(FeMn) and Chinese Script Al6(FeMn) and increase the volume percent of porosity, resulting in a remarkable decrease in the ultimate tensile strength (UTS) and yield strength (YS). For the alloys produced with a pressure of 75 MPa, the addition of Si can also promote the formation of fine Chinese Script {\alpha}-Fe and high number density Al2Cu ({\theta}) phases, resulting in a slight increase in UTS and YS. The strength and elongation of the alloys increases with increasing applied pressure at the same Si level, which are attributed to the elimination of porosity, grain refinement strengthening and solid-solution strengthening. The alloy with addition of 1.1 % Si produced under the applied pressure of 75 MPa shows the best tensile properties, where the UTS, YS and elongation is 237 MPa, 140 MPa and 9.8%, respectively.
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Microstructures and mechanical properties of squeeze cast Al–5.0Cu–0.6Mn alloys with different Fe content
Materials & Design (1980-2015), 2013Co-Authors: Weiwen Zhang, Bo Lin, Datong ZhangAbstract:Abstract The microstructures and mechanical properties of gravity die cast and squeeze cast Al–5.0 wt% Cu–0.6 wt% Mn alloys with different Fe content have been studied using tensile test, optical microscope, scanning electron microscope, electron probe micro-analyzer and image analysis. The results show that four kinds of Fe-rich intermetallics may present in the final microstructures of the alloys: Chinese Script α-Fe (Al15(FeMn)3(CuSi)2) and Al6(FeMn), needle-like β-Fe(Al7Cu2Fe) and Al3(FeMn) when the Fe content increases from 0.1 wt% to 1.5 wt%. In the gravity die cast alloy with 0.5 wt% Fe, the Chinese Script α-Fe presents as the main Fe-rich intermetallics, and a few needle-like β-Fe also exist. When the Fe content increases to 1.0 wt%, the main Fe-rich intermetallics change to needle-like Al3(FeMn) and Chinese-Script Al6(FeMn). The needle-like β-Fe disappears when the Fe content is 0.5 wt% in the squeeze cast alloy with an applied pressure of 75 MPa. Furthermore, the secondary dendritic arm spacing of α(Al), the percentage of porosity and the volume fraction of the second intermetallics decrease distinctly in the squeeze cast alloy compared to the gravity die cast alloy. There is a peak value of ultimate strength and yield strength for the alloy with 0.5 wt% Fe. The elongations of the alloys decrease gradually with increasing Fe content and the elongation of the squeeze cast alloys is two times more than that of the gravity die cast alloys.
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Microstructures and mechanical properties of heat-treated Al–5.0Cu–0.5Fe squeeze cast alloys with different Mn/Fe ratio
Materials Science and Engineering: A, 2013Co-Authors: Weiwen Zhang, Bo Lin, Jianlei Fan, Datong ZhangAbstract:Abstract The Al–5.0 wt% Cu–0.5 wt% Fe alloys with different Mn/Fe ratio were prepared by squeeze casting. Various test techniques, including tensile test, image analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM) were used to examine the microstructures and mechanical properties of the alloys in T5 heat-treated condition. The results show that the β-Fe (Al7Cu2Fe) is stable and its needle-like morphology is maintained after T5 heat treatment. However, the Chinese Script AlmFe, α-Fe or Al6(FeMn) partially transform to a new Chinese Script Cu-rich α(CuFe) (Al7Cu2Fe or Al7Cu2(FeMn)), which is harmful to the mechanical properties of the alloys due to the decrease of the Cu content in α(Al) matrix. The optimal Mn/Fe ratio is determined by the morphology of Fe-rich intermetallics, volume fraction of θ′ and T (Al20Cu2Mn3), size of α(Al) dendrite and porosity. Excessive Mn/Fe ratio will deteriorate the mechanical properties of the alloys due to the increase of the total amount of porosity and the Fe-rich intermetallics. When the Mn/Fe ratio is 1.6 and 1.2 for the applied pressure of 0 MPa and 75 MPa, respectively, the needle-like β-Fe phase is completely converted to the Chinese Script Fe-rich intermetallics. The ultimate tensile strength, yield strength and elongation of the T5 heat-treated alloy with the Mn/Fe ratio of 1.2 and applied pressure of 75 MPa reach 395 MPa, 335 MPa and 14%, respectively.
Hengzhi Fu - One of the best experts on this subject based on the ideXlab platform.
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microstructure transformation from irregular eutectic to complex regular eutectic in directionally solidified al2o3 gdalo3 zro2 ceramics by laser floating zone melting
Journal of The European Ceramic Society, 2016Co-Authors: Jun Zhang, Haijun Su, Hengzhi FuAbstract:Abstract Directionally solidified Al 2 O 3 /GdAlO 3 (GAP)/ZrO 2 (GdSZ) ternary eutectic ceramics have been grown by laser floating zone melting. The microstructure evolution rule is investigated as a function of growth rate. The as-solidified samples present high density (>99%), smooth surface and high diameter stability free of pores and cracks. Increasing the growth rate from 4 to 100 μm/s, the microstructures undergo a transformation from “Chinese Script” irregular eutectic pattern to eutectic colony and to complex regular eutectic patterns (lamellae or rods). The average interphase spacing of the “Chinese Script” microstructure presents an inverse square relationship according to λ = 10.46 × ν −1/2 , where the average interphase spacing λ has the dimension of μm and growth rate ν is in μm/s. While the interphase spacing of the complex regular microstructure is finer. The mechanisms of the microstructure evolution and the effects of ZrO 2 phase on the morphology and domain size of microstructure are discussed in detail.