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Enhanced mechanical performance via Al2O3 whisker reinforcing and microwave sintering in 3Y-TZP ceramics

Ceramics International 2025年

作者： Wang, Chuanmin Lu, Ya Ma, Weigang Zhou, Xinyi Liu, Jinpeng Xiao, Jianzhong Guo, Xin Song, Yijing Ye, Sixian Tran, Nguyen-Minh-An Tan, Hua Zhang, Haibo School of Materials Science and Engineering State Key Laboratory of Material Processing and Die & Mould Technology Huazhong University of Science and Technology Wuhan430074 China School of Mechanical Science & Engineering Huazhong University of Science and Technology Wuhan430074 China Guangdong HUST Industrial Technology Research Institute Dongguan523808 China Faculty of Chemical Engineering Industrial University of Ho Chi Minh City Ho Chi Minh City71420 Viet Nam

To improve the hardness, fracture toughness, and overall mechanical properties of 3Y-TZP ceramics, Al2O3 whiskers were introduced as reinforcing phases. Composite ceramics containing 0.5, 1.0, 1.5, and 2.0 wt% Al2O3 whiskers were fabricated using microwave sintering at 1450 and 1500 °C. The heating rates ranging from 8.3 to 40 °C/min and a holding time of 180 min, following cold isostatic pressing at 200 MPa. The densification behavior, microstructural evolution, and toughening mechanisms were systematically analyzed using scanning electron microscopy, X-ray diffraction, and Vickers indentation. Microwave sintering achieved a relative density of 99.46 ± 0.12 % at 1500 °C with 2.0 wt% Al2O3 whiskers, while phase analysis confirmed the retention of tetragonal zirconia. Compared with conventional sintering, microwave sintering produced finer grain sizes, reducing the average from 566.0 ± 131.0 nm to 400.3 ± 119.3 nm. The incorporation of 2.0 wt% Al2O3 whiskers enhanced mechanical properties, yielding a Vickers hardness of 15.1 ± 0.3 GPa and a fracture toughness of 7.72 ± 0.15 MPa m1/2. The high elastic modulus and elongated morphology of Al2O3 whiskers contributed to toughening through crack deflection, whisker bridging, and whisker penetration, leading to a mixed fracture mode of transgranular and intergranular fractures. These findings demonstrate that Al2O3 whisker reinforcement significantly improves the mechanical performance of 3Y-TZP ceramics, while microwave sintering enhances densification, shortens processing time, and refines microstructure, offering an effective strategy for optimizing zirconia-based composites. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Densification

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Accumulative Effect in Femtosecond Laser Ablation of SiCf/SiC Ceramic Matrix Composites 18

Accumulative Effect in Femtosecond Laser Ablation of SiCf/Si...

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18th National Conference on Laser Technology and Optoelectronics 2023

作者： Rao, Qi Chen, Xiaoxiao Chen, Tao Chen, Jianbo Zhang, Wenwu Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Zhejiang Provincial Key Laboratory of Aeroengine Extreme Manufacturing Technology Zhejiang Ningbo315201 China Faculty of Mechanical Engineering & Mechanics Ningbo University Zhejiang Ningbo315211 China University of Chinese Academy of Sciences Beijing100049 China JiangXi University of Science and Technology Jiangxi Ganzhou341000 China

ISBN: (纸本)9781510668379

Silicon carbide fiber reinforced silicon carbide ceramic matrix composites (CMC-SiCf/SiC) have been widely used in aerospace and other fields due to their excellent properties such as high hardness, oxidation resistance and high temperature resistance. Different from the traditional machining methods, laser processing technology has great application prospects in CMC-SiCf/SiC. In this paper, the single-pulse ablation test and multi-pulse cumulative ablation test of CMC-SiCf/SiC were carried out by femtosecond laser at different powers with a wavelength of 1035 nm. A series of experiments were designed to process the ablation pits on the material surface. The diameter of the ablation pits was observed by laser confocal microscope. The variations of the ablation threshold of CMC-SiCf/SiC surface under different pulse energies and pulse numbers were studied. The results show that the multi-pulse ablation threshold of CMC-SiCf/SiC decreases with the increase of pulse number, and there is a significant cumulative effect. The multi-pulse ablation threshold of CMC-SiCf/SiC is mainly related to the number of pulses, which is determined by two parameters: accumulation factor and single-pulse ablation threshold. The single-pulse ablation threshold of CMC-SiCf/SiC is 1.1914 J/cm2, and the accumulation factor is 0.6245. In femtosecond laser processing, the pulse accumulation effect has a significant influence on the ablation of hard and brittle material CMC-SiCf/SiC. This study can provide technical guidance for process optimization. © 2023 SPIE.

关键词： Silicon carbide

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Dynamic Analysis of Switching Type Disturbance Suppression Control System Based on Disturbance Estimation of Triaxial Active Control Magnetic Bearing

Dynamic Analysis of Switching Type Disturbance Suppression C...

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Annual Conference of Industrial Electronics Society

作者： Hai Maruyama Akira Heya Katsuhiro Hirata Division of Materials and Manufacturing Science Osaka University Osaka Japan Department of Mechanical Systems Engineering Nagoya University Nagoya Japan

A triaxial active control magnetic bearing with an axially asymmetric structure has been developed for a high-temperature turbomachinery. Since this magnetic bearing has a support force interference, disturbance suppression was not possible. A nonlinear compensator has already been proposed to solve this problem. However, the disturbance suppression performance is insufficient. Therefore, this paper proposes a switching type disturbance suppression control system that estimates a disturbance from the states and switches the controller characteristics based on an estimated disturbance. This model improves the disturbance observer performance of the already proposed a variable structure type nonlinear control system. First, the characteristics of the proposed model are presented, followed by the disturbance estimation performance of the proposed model. Next, the disturbance suppression performance of the proposed model and a conventional compensator is compared. The results verify the superiority of the proposed model over conventional compensators.

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Epitaxial Growth and Characterization of Copper Gallate (CuGa2O4) Thin Films by Pulsed Laser Deposition

SSRN

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SSRN 2024年

作者： Emu, Injamamul Hoque Samuels, Brian C. Karmakar, Subrata Hamid, Md. Abdul Shiam, Istiaq Firoz Sarkar, Pallab Kumar Tasnim, Ayesha Haque, Ariful Droopad, Ravi Ingram School of Engineering Texas State University San MarcosTX78666 United States Materials Science Engineering & Commercialization Program Texas State University San MarcosTX78666 United States

High-quality crystalline copper gallate (CuGa2O4) thin films were grown on c-plane sapphire substrates using the pulsed laser deposition (PLD) technique by optimizing the growth parameters (i.e., temperature, oxygen chamber pressure, and laser energy density). The obtained XRD patterns validated that the preferred orientation of the crystalline CuGa2O4 thin film is along the [111] direction, and the crystallinity of the films improved with increasing substrate temperature while maintaining a constant O2 pressure, as assessed by measuring the full width at half maximum (FWHM) of the prominent (222) plane. Reducing the oxygen pressure leads to the emergence of β-Ga2O3 peaks rather than the CuGa2O4 peaks due to the incomplete oxidation of copper (Cu). Subsequent XRD phi (φ) scans revealed a sixfold rotational symmetry of CuGa2O4 and a 30º epitaxial relationship between the film and the sapphire substrate. X-ray photoelectron spectroscopy (XPS) spectra confirmed the presence of Cu1+, Cu2+, and Ga3+ oxidation states in the films. Increasing laser energy density resulted in the complete oxidation of Cu and an increase in the film thickness from 51.8 nm to 183.4 nm. The direct bandgap of CuGa2O4 films was determined to be approximately 4.51±0.01 eV by analyzing the UV-Vis absorbance spectra using the Tauc equation. The refractive index was found to be approximately 2.05±0.01 based on the spectroscopic ellipsometry data. While the impact of increasing laser energy density was negligible on the parameters such as crystal structure, rotational symmetry, oxidation states of gallium (Ga), oxygen (O), bandgap, and refractive index of CuGa2O4 thin film, notable alterations in the oxidation state of Cu and film thickness were observed. © 2024, The Authors. All rights reserved.

关键词： Thin films

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Microstructure and mechanical Performances of Nicofealti High-Entropy Intermetallic Reinforced Cocrfemnni High-Entropy Alloy Composites Manufactured by Selective Laser Melting

SSRN

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SSRN 2024年

作者： Ma, Pan Yang, Hong Zhang, Zhiyu Xie, Xiaochang Yang, Ping Zhang, Han Jia, Yandong Prashanth, Konda Gokuldoss School of Materials Science and Engineering Shanghai University of Engineering Science Shanghai China State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin150001 China Beijing Institute of Aeronautical Materials Beijing101101 China Laboratory for Microstructures Institute of Materials Shanghai University Shanghai200444 China Department of Mechanical and Industrial Engineering Tallinn University of Technology Ehitajate tee 5 Tallinn19086 Estonia CBCMT School of Mechanical Engineering Vellore Institute of Technology Tamil Nadu Vellore630014 India Shanghai University China

Multi-component alloys have been confirmed to be excellent reinforcing phases in high-entropy alloy-based composite. However, achieving a balance between strength and ductility by controlling the reinforcement content remains a major challenge in the design of high-entropy alloy-based composites. In this study, CoCrFeMnNi HEA/NiCoFeAlTi HER high-entropy alloy composites were prepared using SLM technology. Interestingly, gas-atomized NiCoFeAlTi high-entropy intermetallic (HER) powder was selected as the reinforcing phase, and the CoCrFeMnNi HEA matrix was used for comparison. The influence of the reinforcement content on the composite was investigated, and high-performance HEA/HER composites were obtained, with the strengthening mechanism elucidated. The results showed that the composite with 1 wt.% HER reinforcement exhibited the optimal performance, with hardness, yield strength, ultimate tensile strength, and ductility at room temperature being approximately 226.9 HV, 562 MPa, 683 MPa, and 16%, respectively. The excellent mechanical properties at both room and elevated temperatures are attributed to the synergistic effects of heterogeneous microstructure strengthening, grain refinement, and precipitation strengthening. This work provides a foundation for the development of high-entropy alloy composites reinforced by high-entropy intermetallics. © 2024, The Authors. All rights reserved.

关键词： Entropy

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An Extensive Study of the Effects of Packaging Structure and Material Properties on Reliability of Advanced Packages by Charactering the Stress Singularities at Interface Corners

An Extensive Study of the Effects of Packaging Structure and...

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Electronics Packaging Technology Conference (EPTC)

作者： Guang-Chao Lyu Bin Chen Xin-Ping Zhang Min-Bo Zhou Chang-Bo Ke Yiu-Wing Mai School of Materials Science and Engineering and Guangdong Provincial Engineering Technology R&D Center of Electronic Packaging Materials and Reliability South China University of Technology Guangzhou China Department of Mechanical Engineering The Hong Kong Polytechnic University Hong Kong

This paper presents a new approach to acquiring in-plane solutions for the stress singularities at internal junctions where multiple elastic isotropic materials meet, and then establishing the correlation between the singular stress field and the failure of electronic package structures. Extensive analyses have been conducted on the order of the stress singularities in relation to the material properties and interface angles, which address an important yet controversial issue regarding the utilization of the stress singularity for electronic package reliability assessment. The results obtained through calculating the stress singularity orders are further validated using finite element analyses. The basic findings indicate that the analyses of the singularity order can serve as an initial approach to evaluate structural design and system reliability. However, relying solely on the calculations of the stress singularity order is insufficient when exploring the variations in material parameters. Despite that, the calculations of the order of stress singularity still provide valuable guidance for electronic package design and help develop more robust and reliable packaging solutions for integrated circuit devices.

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Dislocation Structure Evolution Pathway in Surface and Bulk Regions of Ni Deformed in Tension: A Comparison

SSRN

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SSRN 2024年

作者： Sun, Qingqing Zhang, Qianru Wang, Shuai Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China School of Materials Sun Yat-sen University Shenzhen518107 China

The study examines the evolution of dislocation structures in pure nickel with specific orientations near [100], [110], and [111]. The dislocation evolution pathways of grains with different orientations in both surface and bulk regions have been systematically investigated. It was observed that the development of dislocation structures in surface and bulk grains is not synchronous. During the early stages of plastic deformation, dislocation self-organization in surface grains is promoted more than in the bulk. However, as the strain increases, the situation is reversed, and cell block formation is largely postponed in the surface region. At high strain levels, orientation dependence of dislocation structures in the Ni surface region basically follows the same rule as the bulk, while at low strain levels, it does not. The slip band emergence on the crystal surface does not necessarily correspond with the dislocation pattern beneath it. The minimum strain level of cell block formation for [110] corner is lower than that for [111] corner. These findings approach our understanding on the deformation mechanism of FCC metals. © 2024, The Authors. All rights reserved.

关键词： Nickel

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Acoustic Field-Assisted Powder Bed Fusion of Tungsten Carbide-Reinforced 316l Stainless Steel Composites

SSRN

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SSRN 2023年

作者： Guo, Anfu Tang, Rongji Guo, Shuai Hu, Yingbin Sheng, Xianliang Zhang, Yibao Zhang, Mingkang Qu, Peng Wang, Shaoqing School of Mechanical and Automotive Engineering Liaocheng University Shangdong Liaocheng252000 China School of Materials Science and Engineering Liaocheng University Shandong Liaocheng252059 China Department of Mechanical and Manufacturing Engineering Miami University OxfordOH45056 United States

Due to its excellent corrosion and oxidation resistance, good formability, and affordability, 316L stainless steel (SS) is widely used in industries such as biomedical, marine, chemical, and water treatment. To further enhance its mechanical properties, scholars have turned to reinforcing 316L SS with ceramic additives. Among ceramic additives, tungsten carbide (WC) is favored due to its good wettability ability to bond closely with iron-based materials. Despite these benefits, defects such as cracks, pores, and spheroidization commonly exist in WC-reinforced metal matrix composites due to the agglomeration of WC particles. In response to these problems, the authors propose a novel method that combines acoustic field (AF) with powder bed fusion (PBF) to process WC-reinforced 316L SS materials. This approach takes advantages of AF’s ability to homogenize materials, smooth out thermal gradient, reduce cracks, and refine grains in liquid materials, while also utilizing PBF’s capabilities to fabricate complex-shaped customized parts with high density and good quality. Experimental results have shown that adding an AF to the PBF can reduce dislocation density, mitigate stress, alleviate cracks, refine grain size, and alter grain shape, ultimately enhancing the tensile properties of WC-reinforced 316L SS composites. By adopting this method, a balanced and enhanced strength and ductility have been achieved, with ultimate tensile strength and percentage elongation falling into a narrow but high range of 750-930 MPa and 44-55%, respectively. © 2023, The Authors. All rights reserved.

关键词： Austenitic stainless steel

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Microstructure evolution of 7050 aluminum forgings during surface cumulative plastic deformation

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Transactions of Nonferrous Metals Society of China 2025年第1期35卷 45-59页

作者： Jian-liang HU Ze-xiong ZHANG Cheng XING Xiu-jiang WU Shi-quan HUANG Hong BO Key Laboratory of Advanced Forging&Stamping Technology and Science Ministry of EducationYanshan UniversityQinhuangdao 066004China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China College of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China Hebei Engineering Technology Research Center of Metal Precision Plastic Processing Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

To elucidate the mechanisms of regulating the microstructure uniformity in 7050 aluminum forgings through surface cumulative plastic deformation(SCPD),the microstructure under different solution treatments was investigated using metallographic observation(OM),electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),and X-ray diffraction(XRD).The findings demonstrate that the most uniform microstructure in the forgings is achieved with a solution treatment at 470℃for 30 *** SCPD process generates a significant number of needle-shaped precipitates,resulting in a higher dislocation density and stored *** treatments alleviate the pinning effect of second-phase particles and facilitate static recrystallization(SRX)in forgings,leading to a reduction in grain ***,mechanical testing results demonstrate 7%−13%increase in tensile strength and more uniform elongation of the forgings in different directions.

关键词： microstructure homogeneity surface cumulative plastic deformation(SCPD) static recrystallization(SRX) dislocation density

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Investigating the influence of environmental conditioning on epoxy resins at quasistatic and high strain rates for material operating limit 36

Investigating the influence of environmental conditioning on...

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36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021

作者： Doshi, Sagar M. Manoharan, Nithinkumar Haque, Bazle Z. Deitzel, Joseph M. Gillespie, John W. Center for Composite Materials University of Delaware NewarkDE19716 United States Department of Materials Science and Engineering Department of Mechanical Engineering Department of Civil and Environmental Engineering Department of Computer and Electrical Engineering University of Delaware NewarkDE19716 United States

ISBN: (纸本)9781713837596

Epoxy resin-based composite panels used for armors may be subjected to a wide range of operating temperatures (-55℃ to 76℃) and high strain rates on the order of 103-104 s-1. Over the life cycle, various environmental factors also affect the resin properties and hence influence the performance of the composites. Therefore, it is critical to determine the stress-strain behavior of the epoxy resin over a wide range of strain rates and temperatures for accurate multi-scale modeling of composites and to investigate the influence of environmental aging on the resin properties. Additionally, the characterization of key mechanical properties such as yield stress, modulus, and energy absorption (i.e. area under the stress-strain curve) at varying temperatures and moisture can provide critical data to calculate the material operating limits. In this study, we characterize mechanical properties of neat epoxy resin, SC-15 (currently used in structural armor) and RDL-RDC using uniaxial compression testing. RDL-RDC, developed by Huntsman Corporation, has a glass transition temperature of ~ 120℃, compared to ~ 85℃ of SC-15. A split Hopkinson pressure bar is used for high strain rate testing. Quasistatic testing is conducted using a screw-driven testing machine (Instron 4484) at 10-3 s-1 and 10-1 s-1 strain rates and varying temperatures. The yield stress is fit to a modified Eyring model over the varying strain rates at room temperature. For rapid investigation of resistance to environmental aging, accelerated aging tests are conducted by immersing the specimens in 100℃ water for 48 hours. Specimens are conditioned in an environmental chamber at 76 ℃ and 88% RH until they reach equilibrium. Tests are then conducted at five different temperatures from 0℃ to 95℃, and key mechanical properties are then plotted vs. temperature. The results presented are an important step towards developing a methodology to identify environmental operating conditions for composite ground vehicle appli

关键词： Epoxy resins

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