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Oxidation behavior of Mo-Si-B alloys at medium-to-high temperatures

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Journal of Materials Science & Technology 2021年第1期60卷 113-127页

作者： Kunming Pan Yanping Yang Shizhong Wei Honghui Wu zhili dong Yuan Wu Shuize Wang Laiqi Zhang Junping Lin Xinping Mao Henan Key Laboratory of High-temperature Structural and Functional Materials National Joint Engineering Research Center for Abrasion Control and Molding of Metal MaterialsHenan University of Science and TechnologyLuoyang 471003China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Nanyang Technological UniversitySingapore State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

Continuous exploration of high-temperature structural materials is being driven by the needs of gasturbine engines capable of withstanding the high-temperature *** low melting points of currently applied superalloys restrain the further improvement of service tempe *** higher melting tempe ratures above 2000℃,Mo-Si-B alloys are regarded as a new generation of ultrahightemperature structural ***,oxidation is a concern for the industrial application of Mo-Si-B ***,an in-depth understanding of the oxidation mechanisms may contribute to solving this issue,whereas relevant reviews about their recent advances are *** the current work,a comprehensively systematic review about the oxidation behaviors of Mo-Si-B alloys is described for this purpose.

关键词： Mo-Si-B alloys Oxidation resistance Alloying and modification Enhancement

AGING PRECIPITATION OF Cu-Zr AND Cu-Zr-Si ALLOYS AND AFFECTED BY COLD WORKING

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Acta Metallurgica Sinica(English Letters) 1990年第3期3卷 222-225页

作者： dong zhili TANG Xiangyun Tsinghua University,Beijing,ChinaHORI Sgigenori FUJITANI Wataru Faculty of Engineering,Osaka University,Japan dong zhili Dept.of Material Science and Engineering,Tsinghua University,Beijing 100084,China

The hardness and electrical conductivity of Cu-Zr and Cu-Zr-Si alloys varying with differ- ent aging regimes were measured and the factors influencing the electrical conductivity were *** is believed that a little Si can refine the precipitates and improve the resistance to *** improvement of materials properties by aging and the effect of cold work were also discussed.

关键词： aging precipitation Cu-Zr alloy

PROCESS OF OXIDE FILM FORMATION ON JOINT INTERFACE OF METAL AND GLASS

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Transactions of Nonferrous Metals Society of China 1991年第1期1卷 66-72页

作者： Ma Jusheng Kaoru KOJIMA Masayosi TAKADA dong zhili Tang Xiangyun Tsinghua University Bey ing 100084China Sumitomo Special Matals Co.Osaka Japan

The *** oxide films on 476 alloy,with a small amount of additive elements such as Si etc.,oxidized in wet hydrogen atmosphere is some times accompanied by the formation of a great many *** form of whiskers grown on the oxide film is of flag pole type with a globe on its *** pole is a spinel single crysul oxide(Fe,Mn)Cr_(2)O_(4) and the globe is a metallic compound(Ni,Fe)_(x)Al_(y) covered with protective Al,Si oxide *** of the metallic globe named while particle is formed at the early stage of heating be tween 700℃ and 900℃.It seems to be extracted from the alloy matrix as a result of arummrum obrusion .Asial growth of pole begins at about 115℃.It is supposed that the whisker grows at the root of a white particle and the interaction effect between the stress of oxide around the particle and the climbing motion of dislocation beneath the *** the alloy surface is covered uniformly with Cr_(2)O_(3) as the ini tai oxide film,its final surface oxide film has no whiskers even after long time oxidation at higher temperature in hydrogen *** surface treatment of base alloy,such mechanical brushing,is very effective for the formation of Cr_(2)O_(3) at initial *** is supposed that the brushed surface may be activated to produce surface reactions by an enrichment of lattice defects.

关键词： sealing alloy oxide film oxide whisker

Highly Efficient and Stable Hydrogen Production in All pH Range by Two-Dimensional Structured Metal-Doped Tungsten Semicarbides

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Research 2019年第1期2019卷 991-1004页

作者： Edison H.Ang Khang N.Dinh Xiaoli Sun Ying Huang Jun Yang zhili dong Xiaochen dong Wei Huang Zhiguo Wang Hua Zhang Qingyu Yan Energy Research Institute Interdisciplinary Graduate SchoolNanyang Technological University637553Singapore Centre for Programmable Materials School of Materials Science and EngineeringNanyang Technological University639798Singapore Institute of Advanced Materials Nanjing Tech UniversityNanjing 210000China School of Physical Electronics University of Electronic Science and Technology of ChinaChengdu 610054China Department of Chemistry City University of Hong KongKowloonHong Kong

Transition-metal-doped tungsten semicarbide nanosheets(M-doped W_(2)C NSs,M=Fe,Co,and Ni)have been synthesized through carburization of the mixture of tungsten trioxide,polyvinylpyrrolidone,and metal *** nanosheets grow directly on the W mesh and have the lateral dimension of several hundreds of nm to a few�m with a thickness of few tens *** is demonstrated that the M-doped W_(2)C NSs exhibit superior electrocatalytic activity for hydrogen evolution reaction(HER).Impressively,the Nidoped W_(2)C NSs(2 at%Ni)with the optimized HER activity show extremely low onset overpotentials of 4,9,and 19 mV and modest Tafel slopes of 39,51,and 87 mV dec−1 in acidic(pH=0),neutral(pH=7.2),and basic(pH=14)solutions,respectively,which is close to the commercial Pt/C *** functional theory(DFT)calculations also demonstrate that the Gibbs free energy for H adsorption of Ni-W_(2)C is much closer to the optimal valueG_(H∗)=-0.073 eV as compared to-0.16 eV of W_(2)***,nearly 100%Faradaic efciency and long-term stability are obtained in those *** realization of highly tolerant metal semicarbide catalyst performing on par with commercial Pt/C in all range of pH ofers a key step towards industrially electrochemical water splitting.

关键词： Highly closer realization

Elucidation of thermally induced internal porosity in zinc oxide nanorods

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Nano Research 2018年第5期11卷 2412-2423页

作者： Albertus D. Handoko Laura-Lynn Liew Ming Lin Gopinathan Sankar Yonghua Du Haibin Su zhili dong Gregory K. L. Goh Institute of Materials Research and Engineering Agency for Science Technology and Research (A＊STAR) Singapore 138634 Singapore School of Materials Science and Engineering Nanyang Technological University Singapore 639798 Singapore Department of Chemistry University College London London WC1H0AJ UK Institute of Chemical and Engineering Sciences Agency for Science Technology and Research (A＊STAR) Singapore 627833 Singapore

In situ electron microscopy, tomography, photoluminescence, and X-ray absorption spectroscopy were utilized to monitor and explain the formation and growth of internal pores within ZnO nanorods. Careful examination using electron microscopy and tomography indicate that nanosized intemal pores start appearing within the individual solution-grown ZnO nanorods upon exposure to 200 ℃. The pore volume growth rate is proportional to the heat treatment time, indicating that the process is diffusion controlled, akin to a reverse Ostwald ripening-like process. A manageable pore growth rate of 1.4-4.4 nm^3·min^-1 was observed at 540 ℃, suggesting that the effective control over internal porosity can be achieved by carefully controlling the heat-treatment profile. Mechanistic studies using X-ray absorption spectroscopy indicated that the pore formation is linked to the significant reduction of the number of zinc vacancies after heat treatment. An optimum condition exists where most of the native surface defects are removed, while the bulk defects are contained within the internal pores. It is also demonstrated that the internal porosity can be exploited to improve the visible light absorption of ZnO. A combination of the lower defect density and improved light absorption of the heat-treated ZnO films thus lead to an increase in the photo- electrochemical response of more than 20× compared to that of the as-grown ZnO.

关键词： zinc oxide solution growth hydrothermal porosity photocatalysis photocurrent

HIGH TEMPERATURE OXIDATION AND STRUCTURE OF SCALE AND WHISKERS FOR Fe-Ni-Cr SEALING ALLOYS

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 147-150页

作者： dong zhili MA Jusheng TANG Xiangyun YOU Liang Tsinghua University,Beijing,China lecturer Department of Materials Science and Engineering,Tsinghua University,Beijing 100084,China Tsinghua Univ Beijing China

The oxidation rate,the growth,morphology and structure of oxide scale and whiskers for Fe-Ni-Cr sealing alloys in H_2-H_2O atmosphere at high temperatures have been studied. The growth rate of scale is controlled by *... 详细信息

关键词： oxidation oxide scale oxide whisker Fe-Ni-Cr sealing alloy

Effect of Aging Parameters on Inconel 718 Fabricated by Laser Directed Energy Deposition

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Chinese Journal of Mechanical Engineering(Additive Manufacturing Frontiers) 2023年第4期2卷 112-121页

作者： Nataniel Yong Syn Tham Grace Rui Si Tay Bingqing Yao Kaiqiang Wu zhili dong School of Materials Science and Engineering Nanyang Technological UniversitySingapore639798Singapore Advanced Remanufacturing and Technology Center(ARTC) Agency for ScienceTechnology and Research(A∗STAR)Singapore637143Singapore School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore639798Singapore

Inconel 718 is a nickel-based superalloy of high interest in high temperature applications such as turbine *** be used in such applications,heat treatments are commonly applied to dissolute Laves phase and to achieve𝛾γ′***,conventional heat treatment methods for wrought Inconel 718 may not be suitable for Inconel 718 fabricated by laser directed energy deposition(LDED)due to its unique microstructure formed during the rapid solidification *** has been a lack of investigation in heat treatments for Inconel 718 fabricated by this process,specifically around the impact of aging parameters on this *** this study,the effects of aging parameters were studied by performing seven different heat treatments,including solutionising and aging *** results indicate that for LDED Inconel 718,a high temperature solution treatment of 1100℃for 1 h followed by single aging at 650℃for 20 h achieved a tensile strength and elongation of 1247 MPa and 23%,***,results indicated that even with a shorter aging time of 10 h,γ′phase was found to be of comparable size to the standard double aged treatment.

关键词： Inconel 718 Laser directed energy deposition Heat treatment Microstructure Additive manufacturing