Effect of an abrupt change in pulling rate on microstructures of directionally solidified Al2O3-Er3Al5O12 eutectic and off-eutectic composite ceramics

Ren, Qun; Su, Haijun; Zhang, Jun; Liu, Haifang; Ma, Weidan; Fan, Guangrao; Zhao, Di; Guo, Min; Liu, Lin; Fu, Hengzhi

doi:10.1016/j.ceramint.2018.12.151

Cited by 6 publications

(4 citation statements)

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“…2,[4][5][6] The micromorphology of the eutectic oxides is primarily determined by two factors: the solidification rate and the off-eutectic composition. 1,7,8 Lower solidification rates tend to result in a "Chinese script" 3D interpenetrating microstructure, whereas moderate higher rates produce regular 2D arranged microstructures such as rods or lamellae. 2,6,9 However, with higher solidification rates or off-eutectic compositions, the coupled growth of the eutectics may break, and single-phase dendrites or cells will form instead.…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies have focused on the microstructure modification of directionally solidified eutectic oxide composites to improve their mechanical properties 2,4–6 . The micromorphology of the eutectic oxides is primarily determined by two factors: the solidification rate and the off‐eutectic composition 1,7,8 . Lower solidification rates tend to result in a “Chinese script” 3D interpenetrating microstructure, whereas moderate higher rates produce regular 2D arranged microstructures such as rods or lamellae 2,6,9 .…”

Section: Introductionmentioning

confidence: 99%

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Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO₃–RE₂Zr₂O₇ eutectic oxide

et al. 2023

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In this study, complex GdAlO3‐Gd2Zr2O7 and high‐entropy REAlO3‐RE2Zr2O7(RE = Nd, Sm, Gd, Eu and Dy) composites with an equiaxed dendrite structure at eutectic composition are successfully fabricated using a gas levitation containerless solidification method. The unique microstructure of the composites is characterized, and the evolution process of the dendritic structure is explained. The formation of dendrites at eutectic composition is attributed to the rapid cooling induced by the shutoff of lasers and the homogeneous temperature field and nucleation achieved through gas levitation. The GdAlO3‐Gd2Zr2O7 and high‐entropy oxide composites exhibit enhanced fracture toughness compared to the bulk samples fabricated by solid‐state sintering methods. The fracture toughness increases by 44% for GdAlO3‐Gd2Zr2O7 bulk sample and 34% for high‐entropy REAlO3‐RE2Zr2O7 bulk sample, which can be attributed to the complicated interfaces introduced by the equiaxed dendritic microstructure and the high thermal mismatch stress between two phases. Additionally, the high‐entropy REAlO3‐RE2Zr2O7 oxides exhibit excellent high‐temperature stability, with no significant change in dendritic microstructure or fracture toughness even after holding at 1573K for 100 hours. These findings suggest the potential of high‐entropy eutectic oxide ceramics with dendrite microstructure for advanced engineering applications.This article is protected by copyright. All rights reserved

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO₃–RE₂Zr₂O₇ eutectic oxide

et al. 2023

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“…and they found that the regular arrangement was generally formed under high growth rates 13 . They discussed the transformation of microstructure from irregular eutectic to regular eutectic, probable adjustment mechanism of eutectic spacings, and the effect of an abrupt change in pulling rate on microstructures of Al 2 O 3 /ErAG 14,15 . Besides, Sun et al.…”

Section: Introductionmentioning

confidence: 99%

Preparation, microstructures, and mechanical properties of directionally solidified Al₂O₃/Lu₃Al₅O₁₂ eutectic ceramics

Sun

Zhou

et al. 2021

Int J Applied Ceramic Tech

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Al2O3/Lu3Al5O12 (LuAG) directionally solidified eutectic (DSE) ceramics with two solidification rates were prepared utilizing optical floating zone (OFZ) technique. The microstructures (eutectic morphology, preferred growth direction and interface orientation) of Al2O3/LuAG were characterized, and the mechanical properties (Vickers hardness and fracture toughness) were compared with those of Al2O3/REAG (RE = Y, Er, and Yb). Results show that Al2O3/LuAG with solidification rate of 30 mm/h has established preferred growth direction in both Al2O3 and LuAG phases with cellular eutectic structures. While Al2O3/LuAG with solidification rate of 10 mm/h only shows preferred growth direction in Al2O3 phase and presents degenerate irregular eutectic microstructures. Besides, Al2O3/LuAG exhibits higher hardness compared with Al2O3/REAG (RE = Y, Er, and Yb). In addition, a special attention is focused on the relations among rare earth ionic radius, eutectic microstructures, and mechanical properties of these DSE ceramics. It is demonstrated that a smaller rare earth ionic radius could lead to larger eutectic interspacing as well as higher Vickers hardness of DSE Al2O3/REAG, revealing the possibility and feasibility of microstructure control and mechanical properties optimization for DSE Al2O3/REAG ceramics by tailoring the rare earth elements.

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“…Besides the above excellent thermal stability and mechanical properties at high temperatures, it is also believed that rare earth ions in the crystals may emit radiation in narrow bands. These comprehensive properties make directionally solidified eutectics promising candidates that can meet the thermo-structural challenges in thermofotovoltaic (TPV) converter applications [11][12][13][14][15][16] . The selective thermal emission results illustrated that Al2O3/ErAG showed intense emission band and could match with the GaSb photovoltaic cells [17] and Al2O3/Yb3Al5O12(YbAG) showed an intense selective emission band at 1 μm, which was compatible with the silicon photovoltaic cells [18][19] .…”

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confidence: 99%

Directionally Solidified Al₂O₃/Er₃Al₅O₁₂ and Al₂O₃/Yb₃Al₅O₁₂ Eutectic Ceramics Prepared by Optical Floating Zone Melting

Sun¹,

Zhou²,

Du³

et al. 2021

Journal of Inorganic Materials

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Al2O3/Er3Al5O12(ErAG) and Al2O3/Yb3Al5O12(YbAG) eutectic rods with fine and homogeneous microstructure, free from cracks or pores, were directionally solidified using optical floating zone method at growth rate of 10 mm/h. The crystallographic orientation, preferred orientation, and 3D distribution of Al2O3 and Er3Al5O12/Yb3Al5O12 phases in the terminal growth zone of Al2O3/ErAG and Al2O3/YbAG eutectics were investigated by EBSD and high-resolution X-ray microscope. Vickers hardness of the as prepared Al2O3/ErAG and Al2O3/YbAG eutectics are determined as (13.5±0.4) GPa and (12.8±0.1) GPa, respectively. The fracture toughness results of Al2O3/ErAG and Al2O3/YbAG are (3.0±0.2) MPa• m 1/2 and (3.2±0.1) MPa• m 1/2 , respectively.

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Effect of an abrupt change in pulling rate on microstructures of directionally solidified Al2O3-Er3Al5O12 eutectic and off-eutectic composite ceramics

Cited by 6 publications

References 38 publications

Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO₃–RE₂Zr₂O₇ eutectic oxide

Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO₃–RE₂Zr₂O₇ eutectic oxide

Preparation, microstructures, and mechanical properties of directionally solidified Al₂O₃/Lu₃Al₅O₁₂ eutectic ceramics

Directionally Solidified Al₂O₃/Er₃Al₅O₁₂ and Al₂O₃/Yb₃Al₅O₁₂ Eutectic Ceramics Prepared by Optical Floating Zone Melting

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Effect of an abrupt change in pulling rate on microstructures of directionally solidified Al2O3-Er3Al5O12 eutectic and off-eutectic composite ceramics

Cited by 6 publications

References 38 publications

Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO3–RE2Zr2O7 eutectic oxide

Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO3–RE2Zr2O7 eutectic oxide

Preparation, microstructures, and mechanical properties of directionally solidified Al2O3/Lu3Al5O12 eutectic ceramics

Directionally Solidified Al2O3/Er3Al5O12 and Al2O3/Yb3Al5O12 Eutectic Ceramics Prepared by Optical Floating Zone Melting

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Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO₃–RE₂Zr₂O₇ eutectic oxide

Dendrite microstructure formation and enhanced toughness in high‐entropy REAlO₃–RE₂Zr₂O₇ eutectic oxide

Preparation, microstructures, and mechanical properties of directionally solidified Al₂O₃/Lu₃Al₅O₁₂ eutectic ceramics

Directionally Solidified Al₂O₃/Er₃Al₅O₁₂ and Al₂O₃/Yb₃Al₅O₁₂ Eutectic Ceramics Prepared by Optical Floating Zone Melting