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Effect of lanthanum on microstructure of a nickel-based single crystal superalloy

China Foundry 2025年第1期22卷 55-64页

作者： Hong Gao Kai Guan Ren-jie Cui Jian-chao Qin Zi-han Zhao Zhao-hui Huang Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical MaterialsBeijing 100095China

To enhance the high-temperature oxidation resistance and mechanical properties of a secondgeneration nickel-based superalloy,various concentrations of lanthanum(La)ranging from 5.0×10^(-5)wt.%to 3.4×10^(-4)wt.%are added to the *** microstructure of the nickel-based single crystal superalloy with trace of La was examined by means of SEM,EDS and *** show the addition of La decreases the segregation of elements and increases the amount ofγ/γ′eutectics of the as-cast alloy,and in the interdendritic region,the growth of eutectics is accompanied by the growth of strip clusters composed of Ni_(5)La and Ni_(3)*** the La content in the alloy increases,the proportion of Ni_(5)La in the cluster *** heat treatment,incipient melting occurs in the cluster regions,leading to an increase in microporosity compared to the original as-cast ***,the heat treatment alters the shape of the clusters from a strip morphology to an elliptical one,and it changes their composition from Ni_(5)La and Ni_(3)Ta to a combination of Ni_(5)La,Ni_(3)Ta,and MC carbides.

关键词： single crystal superalloy lanthanum microstructure heat-treatment precipitate phase

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Pronounced impact of size and shape effects on creep rupture life of a K439B superalloy combustion chamber casting simulator

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China Foundry 2025年第2期22卷 215-221页

作者： Wen-tong Liu Yi-dong Wu Lei Gao Jing-yang Chen Cheng-bo Xiao Xi-dong Hui State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical MaterialsBeijing 100095China

The size and shape effect(SSE)of components has become a critical issue for mechanical properties,application reliability,and *** this study,the creep rupture life(CRL)of components with different wall thicknesses and positions in a combustion chamber casing simulator made of K439B superalloy was *** intrinsic mechanisms of the SSE were explored from the dendrite structure,volume fraction and size of theγ'phase,and element segregation,*** is shown that this casting exhibits a strong SSE of creep rupture life,characterized by a significant difference in the CRL values up to 60%with the variation of wall thickness and position in the *** terms of casting technology,the influence of SSE on CRL is actually determined by the cooling *** SSE on the creep rupture life originates from the dendrite structure(such as the secondary dendrite arm spacing),volume fraction size of theγ'phase in the dendrite trunk,and elements segregation *** work may have implications for the design and application of engineering components with large sizes and complex structures.

关键词： K439B superalloy size and shape effects creep rupture life cooling rate γ'phase combustion chamber casing simulator

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Properties of Gadolinium-doped Silica-based Ceramic Core materials for Blade Neutron Imaging Detection

Properties of Gadolinium-doped Silica-based Ceramic Core Mat...

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Chinese materials Conference 2024, CMC 2024

作者： Si, Yuan Li, Xin Niu, Shuxin Zhou, Tingting Wang, Yue Wang, Ke Yang, Xiaowei Fan, Yiming Shi, Zhenmei Guo, Xinlong Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials Beijing100095 China

Ceramic cores doped with gadolinium oxide can perform neutron photographic examination of inner cavity residual cores of hollow turbine blades containing complicated frameworks. This paper systematically investigates the performance of silicon-based ceramic cores after adding Gd2O3. The experimental results indicate that increasing the Gd2O3 content cannot significantly affect the ceramic cores’ room-temperature flexural strength and shrinkage. In contrast, it considerably influences the high-temperature deflection. When adding Gd2O3 is 1 wt%, the core’s high-temperature deflection decreases by 80%. The XRD results demonstrate that adding gadolinium oxide inhibits the decrease in the high-temperature deflection caused by the precipitation of square quartz. This provides a guiding basis and an improvement direction to optimize the performance of gadolinium-doped ceramic cores for the subsequent application in neutron detection. © 2025 Institute of Physics Publishing. All rights reserved.

关键词： Turbine components

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Effects of shell temperature on microstructures and stress rupture properties of a hot resistant single crystal superalloy

Effects of shell temperature on microstructures and stress r...

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Chinese materials Conference 2024, CMC 2024

作者： Shi, Zhen-Xue Wang, Xiao-Guang Liu, Shi-Zhong Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials Beijing100095 China

The hot resistant single crystal superalloy test bars were cast using shell temperature 1510℃ and 1550℃ on the directional solidification industrial furnace. The microstructure of the alloy prepared using two shell temperature was observed by optical microscope and scanning electron microscope. The stress rupture life of the alloy at 980℃/300MPa was tested. The effect of shell temperature on microstructure and stress rupture lives of the hot resistant alloy was studied. The results display that the dendrite space distance and γ-γ′ eutectic content decrease, the extent of elements segregation decreases, the dimension of γ′ precipitate decreases slightly with increase of the shell temperature. The volume content of micropores of the alloy reduces, dimension of γ′ precipitate reduces, cubic degree of γ′ precipitate slightly increases with increase of shell temperature. The stress rupture life of the alloy increases with rise of shell temperature. © 2025 Institute of Physics Publishing. All rights reserved.

关键词： Single crystals

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Engineering design of feedstock powder and relevant thermal-mechanical performance of thermal/environmental barrier coatings

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Journal of advanced Ceramics 2025年第2期14卷 37-56页

作者： Xinchang Feng Fangwei Guo Lirong Luo Yuzhang Wang Yun Long Xiaofeng Zhao Fei Pan Lei Guo Qingfeng Zeng Jing Feng Chunlei Wan Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China National Engineering Research Center of Special Equipment and Power System for Ship and Marine Engineering Shanghai 200030China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Advanced Nuclear Energy Technology Nuclear Power Institute of ChinaChengdu 610213China Innovative Sensor Technology IST AG Ebnat-Kappel 9642Switzerland School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianmushan Laboratory Hangzhou 311115China School of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

The development of aeroengine with a high thrust-weight ratio poses great challenges for current top-coating thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) in service. Medium/high-entropy ceramics are highly promising candidate material for advanced TBCs/EBCs owing to their low thermal conductivity, high melting point, high-temperature stability, and calcium–magnesium–alumino–silicate (CMAS) resistance. Most feedstock powder used for medium/high-entropy TBCs/EBCs is prepared via traditional spray drying, which cannot fully exploit the advantages of multicomponent ceramics. The density, sphericity, inner structure, and flowability of feedstock powder affect their melting state during the thermal spraying process, which strongly affects the microstructure and properties of the deposited coatings. Therefore, the deposited coatings exhibit phase segregation, amorphous phases, and microstructure defects owing to unpredictable variations in feedstock powder with random morphologies and structures. Here, the structure and properties of feedstock powder prepared by state-of-the-art granulation technologies and their influences on the deposited coatings were systematically investigated, which can provide guidance for configuration optimization of feedstock powder and the manufacturing accuracy of the deposited coating. This review aims to bridge the gap between cutting-edge ceramics and advanced engineering technologies, thus providing concrete background knowledge and crucial guidelines for designing and developing TBCs/EBCs.

关键词： thermal/environmental barrier coatings(TBCs/EBCs) spraying ceramic powder multiscale structure control high-entropy ceramics thermal-mechanical performance

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Nanostructured amorphous Al2O3-La2O3 composites through controlled spark plasma sintering based on super-cooled liquid region

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Ceramics International 2025年

作者： Wang, Shuhuai Xu, Xiqing Wang, Jianglin Yang, Yongkang Yang, Shuqi Zhao, Peng Niu, Shuxin Li, Xin School of Materials Science & Engineering Chang ‘an University Xi'an710061 China Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials Beijing100095 China

Nanostructured amorphous composites exhibit superior mechanical properties compared to crystalline materials due to their disordered atomic arrangement and high defect density. Spark plasma sintering (SPS) is a suitable technique for in-situ synthesis of nano-amorphous composites, allowing densification of amorphous powders via viscous sintering. In this work, amorphous nanopowders of Al2O3-La2O3(AL), Al2O3-La2O3-ZrO2(ALZ), and Al2O3-ZrO2(AZ) were prepared using sol-gel method, followed by densification into nanostructured amorphous composites via SPS in the super-cooled liquid region (SCLR). The AL sample demonstrates a uniform structure, achieving the maximum relative density of 98.1 % along with minimum crystallinity of 30.22 % after SPS at 890 °C. However, with increasing SPS temperature, the relative density of AL sample decreases instead of increasing. This phenomenon is due to the promotion of amorphous-to-crystalline phase transition at high temperatures, which inhibits the viscous flow of amorphous phase during SPS and hinders the densification. Attributed to the narrow SCLR of AZ and ALZ systems, they are faced with the competition between crystallization and structural densification. The crystallinity values are 64.86 % and 51.16 % for AZ and ALZ systems, while the maximum relative densities were 91.9 % and 96.6 %. The SCLR is confirmed as a primary factor to regulate the competition between relative density and crystallization of amorphous powders, and AL system with widest SCLR (ΔTx = Tx-Tg = 72 °C) is beneficial to the densification of nanostructured amorphous composites. Furthermore, STEM-BF and HRTEM reveal nanocrystalline precipitation from amorphous phase matrix during sintering process, and the nanoindentation tests indicate superior mechanical propriety of AL nanostructured amorphous composites. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Nanocrystals

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Polarization-contrcoled chiral trransport

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Light(science & Applications) 2025年第3期14卷 822-830页

作者： Hang Zhu Jian Wang Andrea Alu Lin Chen Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China Photonics Initiative Advanced Science Research CenterCity University of New YorkNew YorkNY 10031USA physics Program Graduate CenterCity University of New YorkNew YorkNY 10016USA Shenzhen Huazhong University of Science and Technology Research Institute Shenzhen 518063China Key Laboratory of High Temperature Electromagnetic Materials and Structure of MOE Wuhan University of Science andTechnologyWuhan430081China

Handedness-selective chiral transport is an intriguing phenomenon that not only holds signifcant importance for fundamental research but also carries application prospects in fields such as optical communications and ***,on-chip chiral transport devices are static,unable to modulate the output modes based on the input *** limits both device functionality reconfiguration and information transmission ***,we propose to use the incident polarization diversity to control the Hamiltonian evolution path,achieving polarization-dependent chiral *** mapping the evolution path of TE and TM polarizations onto elaborately engineered double-coupled waveguides,we experimentally demonstrate that different polarizations yield controllable modal *** work combines Multiple-lnput,Multiple-Output,and polarization diversity concepts with chiral transport and challenges the prevailing notion that the modal outputs are fixed to specific modes in chiral transport,thereby opening pathways for the development of on-chip reconfigurable and high-capacity handedness-selective devices.

关键词： polarization controlled handedness selective control hamilton modulate output modes incident polarization diversity optical communications chiral transport fundamental research

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Enhancing corrosion resistance of MAO coatings on Al alloy LY12 through in situ co-doping with zinc phosphate and cerium phosphate

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Corrosion Communications 2025年第1期17卷 35-43页

作者： Chao Yang Tao Ying Aihui Huang Jian Huang Pinghu Chen Paul K.Chu Xiaoqin Zeng National Engineering Research Center of Light Alloy Net Forming School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming School of Materials Science and Engineering Shanghai Jiao Tong University Department of Chemistry University of Munich(LMU) College of Mechanical Engineering Key Laboratory of Hunan Province of Equipment Safety Service Technology under Extreme Environment University of South China Department of Physics Department of Materials Science&Engineering and Department of Biomedical Engineering City University of Hong Kong

Corrosion of aluminum（Al） alloys during service limits many applications. Micro-arc oxidation（MAO） coatings can enhance corrosion resistance, but porous defects in the films undermine their effectiveness. Here, by mixing a phosphate electrolyte with soluble Zn and Ce salts, zinc phosphate and cerium phosphate co-doped MAO corrosion-resistant coating is prepared on Al alloy LY12. Zinc phosphate and cerium phosphate are incorporated in situ to form an amorphous encapsulated nanocrystalline structure. During long-term corrosion, Zn2+is released and deposited as corrosion products Zn（OH）2to cover weak corrosion micro-regions in the coating. Simultaneously, Ce3+released from MAO coating co-doped with zinc phosphate/cerium phosphate forms Zn（OH）2/Ce（OH）3due to the small solubility product Kspto further enhance corrosion resistance. Compared to pristine Al alloy,corrosion potential increases from -1.306 to -0.819 VSCE, and corrosion current density decreases by 4 orders of magnitude from 2.6 × 10-6to 2.5 × 10-10A·cm-2. Co-doped MAO coating significantly enhances corrosion resistance of Al alloy LY12 and shows great potential for a wide range of applications.

关键词： Aluminum alloys Micro-arc oxidation coating Corrosion resistance Zinc phosphate Cerium phosphate

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Densification, microstructure, and mechanical properties of WMo–Al2O3 alloy fabricated by spark plasma sintering

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Ceramics International 2025年

作者： Cui, Liya Wang, Changji Wei, Shizhong Dou, Caihong Zhao, Ziwen Chen, Chong Dong, Di Pan, Kunming School of Materials Science and Engineering Henan University of Science and Technology Luoyang471000 China Longmen Laboratory Luoyang471000 China Henan Key Laboratory of High-temperature Structural and Functional Materials Henan University of Science and Technology Luoyang471003 China Advanced Technology & Materials Co. Ltd Beijing100081 China

In the spark plasma sintering process, different sintering temperatures (1500–1900 °C) and sintering times (6–20 min) were used for the consolidation of WMo–Al2O3 powder. The results show that the highest relative density of the WMo–Al2O3 alloy was stable at 96 % when the sintering temperature was 1600 °C and the holding time was 10 min;under these conditions, the alloy had no obvious change in phases and a grain size of 0.73 μm. The stress exponent (n) of the diffusion process was less than 0.5, indicating that the densification mechanism of WMo–Al2O3 alloy is atomic diffusion between grain boundaries and particle rearrangement caused by grain boundary slip. The microhardness of the WMo–Al2O3 alloy first increased and then decreased with increasing temperature, which was attributed to the low density, resulting in low microhardness at low sintering temperatures. In addition, the microhardness increased with increasing relative density. When the temperature was further increased and the relative density remained unchanged, the WMo–Al2O3 alloy grain size increased and the hardness decreased. Under holding at 1600 °C for 10 min, the grain size was 0.73 μm, the hardness reached 721.3 HV, and the relative density reached 96.45 %. A transition layer existed in the interface region between the WMo solid solution and the Al2O3 particles, formed by mutual diffusion and reaction between the Al2O3 particles and the WMo matrix. The phase boundary indicated a good combination of Al2O3 particles with the WMo matrix, and the width of the interface bonding region was approximately 5 nm. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Densification

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Microstructure evolution of K439B Ni-based superalloy casting with varying cross-sections by experiments and simulations

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Transactions of Nonferrous Metals Society of China 2025年第4期35卷 1182-1196页

作者： Da-shan SUI De-peng ZHOU Yang LIU Yu SHAN An-ping DONG Institute of Forming Technology&Equipment School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200030China Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Casting experiments and macro-micro numerical simulations were conducted to examine the microstructure characteristics of K439B nickel-based superalloy casting with varying cross-sections during the gravity investment casting ***,microstructure analysis was conducted on the casting using scanning electron microscopy(SEM)and electron backscatter diffraction(EBSD).Subsequently,calculation of the phase diagram and differential scanning calorimetry(DSC)tests were conducted to determine the macro-micro simulation parameters of the K439B alloy,and the cellular automaton finite element(CAFE)method was employed to develop macro-micro modeling of K439B nickel-based superalloy casting with varying *** experimental results revealed that the ratio of the average grain area increased from the edge to the center of the sections as the ratio of the cross-sectional area *** simulation results indicated that the average grain area increased from 0.885 to 0.956 mm^(2)as the ratio of the cross-sections increased from 6꞉1 to 12꞉*** experiment and simulation results showed that the grain size became more heterogeneous and the grain shape became more irregular with an increase in the ratio of the cross-sectional area of the *** modeling was an effective method to simulate the microstructure evolution of the K439B alloy and ensure the accuracy of the simulation.

关键词： K439B nickel-based superalloy cellular automaton cellular automaton finite element method varying cross-section investment casting microstructure evolution

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