检索结果-南通市图书馆

Cyclic oxidation behavior of Ni_(3)Al-based single crystal alloy IC21

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2023年第5期42卷 1656-1662页

作者： Tian-Tian Yang Xin Zhou Shu-Suo Li Yan-Ling Pei sheng-kai gong School of Materials Science and Engineering Beihang UniversityBeijing100191China

In this study,the cyclic oxidation tests of the Ni3Al-based single-crystal super alloy IC21 were carried out at 800,900,950,1000,1050 and 1100℃in air.The present study shows that the complex oxide scale on the surface of the alloy is made up of an outer columnar NiO layer,an intermediate mixture of NiO and NiAl2O4layer with a small amount of Mo oxides and an inner continuous layer ofα-Al_(2)O_(3).The cyclic oxidation kinetics curves show that oxidation resistance at 800,900,950,1000 and1050℃seems to follow a similar law and is better than that at 1100℃.The overall weight changes at 1100℃follows a parabolic law.Spallation and severe rumpling of the oxide scale are observed on the surface of the alloy at1100℃,revealing the occurrence of disastrous oxidation.

关键词： Ni_(3)Al Thermal cycling Oxidation Microstructure

Microstructure and creep properties of Ni-based single-crystal superalloys with Mo/Al addition at 760℃/850 MPa

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2023年第11期42卷 3806-3813页

作者： Pei-Shan Cao Hui Wang Yi Ru Yun-Fei Liang sheng-kai gong Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing100191China

The effect of Mo and Al addition on the microstructure as well as creep rupture properties at760.C/850 MPa was investigated by transmission electron microscopy(TEM)in a Ni-based single-crystal(SC)alloy with the composition of Ni-6.5Al-8.0Mo-2.4Cr-6.2Ta-4.9Co-1.5Re-(0.01-0.05)Y(wt%).The microstructure analysis shows that 0.5 wt%Al addition induces rapid decrease in creep rupture life,and this can be attributed to the formation of dense stacking faults cutting intoγ'precipitates,which can be explained by the increase in Orowan stress caused by the narrowerγchannel width and the decrease in stacking faults energy.Besides,1.5 wt%Mo addition increases the anti-phase boundary energy and decreases the stacking faults energy,resulting in fewer stacking faults and thus a slight decrease in the creep rupture life.

关键词： Ni-based single-crystal superalloy Transmission electron microscopy Stacking faults Mo and Al addition Creep rupture properties

Oxidation behaviour of electron beam physical vapour deposition β-NiAlHf coatings at 1100℃ in dry and humid atmospheres

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2016年第7期35卷 513-519页

作者： kai Yan Hong-Bo Guo Hui Peng sheng-kai gong School of Materials Science and Engineering Beihang University Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology Beihang University

NiA1 intermetallic compounds attract increas- ing attention for high-temperature applications due to their combination of excellent properties, especially as metallic protective coatings on superalloys or as bond coats in thermal barrier coatings （TBCs）. Oxidation behaviour of the β-NiA1Hf coatings prepared by electron beam physical vapour deposition （EB-PVD） was investigated at 1100 ℃ for short time and 100h in 20% 02＋Ar and 15 % H20 ＋ Ar, respectively. The results of mass changes re- veal that the addition of minor reactive element Hf sig- nificantly improves the cyclic oxidation resistance of the 13- NiA1 coatings in both dry and humid atmospheres. During the initial oxidation stage, water vapour retards the phase transformation from 0-A1203 to a-A1203. Moreover, com- pared with the case in dry atmosphere, water vapour sig- nificantly reduces the surface roughness of the oxide scales formed on EB-PVD β-NiA1Hf coatings after 100 h cyclic oxidation, which corresponds with the difference of surface morphologies of the oxide scales.

关键词： β-NiA1Hf coatings Water vapour Oxidation Phase transformation Roughness

Deposition of TiN/TiAlN multilayers by plasma-activated EB-PVD:tailored microstructure by jumping beam technology

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2017年第8期36卷 651-658页

作者： Guo-Yuan Yang Hui Peng Hong-Bo Guo sheng-kai gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology Beihang UniversityBeijing 100191China Key Laboratory of Aerospace Materials and Performance(Ministry of Education) Beihang UniversityBeijing 100191China

Plasma-activated electron beam-physical vapor deposition（EB-PVD）was used for depositing nitride multilayer coatings in this work.Different from the conventional coating methods,the multilayers were obtained by manipulating electron beam（EB）to jump between two different evaporation sources alternately with variable frequencies（jumping beam technology）.The plasma activation was generated by a hollow cathode plasma unit.The deposition process was demonstrated by means of tailoring TiN/TiAlN multilayers with different modulation periods（M1：26.5 nm,M2：80.0 nm,M3：6.0 nm,M4：4.0 nm）.The microstructure and hardness of the multilayer coatings were comparatively studied with TiN and TiAlN singlelayer coatings.The columnar structure of the coatings（TiN,TiAlN,M1,M2）is replaced by a glassy-like microstructure when the modulation period decreases to less than 10 nm（M3,M4）.Simultaneously,superlattice growth occurs.With the decrease of modulation period,both the hardness and the plastic deformation resistance（H^3/E^2,H-hardness and E-elastic modulus）increase.M4coating exhibits the maximum hardness of（49.6±2.7）GPa and the maximum plastic deformation resistance of^0.74 GPa.

关键词： Nano-multilayer coatings Superlattice Plasmaactivation TiN/TiAlN EB-PVD Hardness

Existence patterns of Dy in β-NiAl from first-principles calculations

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2016年第4期35卷 356-360页

作者： Tian Zhang Hong-Bo Guo sheng-kai gong Hui-Bin Xu School of Materials Science and Engineering Beihang University

Intermetallic compound β-NiA1 is a promising material in high temperature applications due to its high melting temperature, high strength, low density, and good oxidation resistance. However, its application remains limited because of its relatively poor cyclic oxidation resistance. Addition of reactive element （RE） Dy can improve the cyclic oxidation of NiA1 alloys significantly. However, the mechanism of Dy addition is not clear. Even the existence pattern of Dy in NiA1 is unspecified. Therefore, in the present study, the impurity formation energies of Dy in stoichiometric NiA1, Ni-rich, and Al-rich NiA1 for the substitution cases were studied by first-principles density functional theory. The results show that Dy could hardly substitute for either Ni or A1 atoms in NiA1. However, calculations for dissolution energies show that Dy could be easily dissolved in AI vacancies in all three types of NiA1, which provides a new existence pattern of Dy in NiA1 beyond experimental detection.

关键词： Existence pattern Dy A1 vacancies First-principles

Thermal cycling performance of La_(2)Ce_(2)O_(7)/YSZ TBCs with Pt/Dy co-doped NiAl bond coat on single crystal superalloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第9期40卷 2568-2578页

作者： Zi-Min Zhou Hui Peng Lei Zheng Hong-Bo Guo sheng-kai gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology Beihang UniversityBeijing 100191China Key Laboratory of Aerospace Materials and Performance(Ministry of Education) Beihang UniversityBeijing 100191China

Thermal barrier coatings(TBCs) consisting ofLa_(2)Ce_(2)O_(7)(LCO) and Y_(2)O_(3)-stabilized-ZrO_(2)(YSZ) doubleceramic layer and Dy/Pt co-doped NiAl bond coat were produced by electron beam physical vapor deposition(EBPVD). Thermal cyclic performance of the TBCs was evaluated by flame shock testing at 1300 ℃. For comparison, the TBCs with a undoped NiAl bond coat were also studied. The microstructural evolution and failure mechanisms of the above TBCs during thermal cycling were investigated. Spallation failure of the TBCs with the undoped bond coat occurs after around 500 cycles by cracking at the interface between YSZ ceramic layer and thermally grown oxides(TGO) layer. The TBCs with Pt/Dy modified bond coat reveal improved interface bonding even after 1200 thermal cycles, whereas some delamination cracks are presented in the LCO layer. On the other hand,the Pt/Dy modified bond coat effectively suppresses the formation of the needle-like topologically closed packed phases(TCP) in the single crystal superalloy.

关键词： Thermal barrier coatings NiAl bond coat Pt/Dy co-doping Electron beam physical vapor deposition Thermal cycling Interdiffusion

Partitioning behavior and lattice misfit of γ/γ’phases in Ni-based superalloys with different Mo additions

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第4期40卷 920-927页

作者： Zhe Ma Yan-Ling Pei Liang Luo Lu Qin Shu-Suo Li sheng-kai gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China

A low-density single crystal(LDS) alloy with the composition of high Mo content was designed.The extra 1.5 wt% Mo was added in the Alloy A with the composition of Ni-6.5 Al-8.0 Mo-2.4 Cr-6.2 Ta-4.9 Co-1.5 Re-(0.01-0.05) Y(wt%) to study the influence of Mo on the lattice parameter and partitioning behavior.Scanning electron microscope(SEM) with energy-dispersive spectrometer(EDS),transmission electron microscopy(TEM)and high-temperature X-ray diffraction(HT-XRD) were used to observe the microstructure,analyze the elemental content and measure the lattice parameter of the alloys.The natural lattice misfit was calculated by lattice constants which were measured by HT-XRD at the temperature from 25 to 1150℃,and the results showed that the lattice misfit would be more and more negative with temperature increasing.It was found that 1.5 wt% addition of Mo will increase the absolute value of the lattice misfit of γ/γ’phases and the volume fraction of γ’,and at the same time,influence the elemental distribution in γ and γ’ phases,especially Re and Cr.Re has a higher partitioning ratio(k) after the addition of Mo.

关键词： Ni-based superalloys Mo Lattice misfit High-temperature X-ray diffraction(HT-XRD) Partitioning behavior

Microstructure stability of γ’+β Ni-Al coated single-crystal superalloy N5 annealed at 1100℃

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第3期40卷 693-700页

作者： Jing-Yong Sun Liang-Liang Wei Qiu-Shi Li sheng-kai gong Hong-Bo Guo School of Energy and Power Engineering Beihang UniversityBeijing 100191China School of Materials Science and Engineering Beihang UniversityBeijing 100191China Key Laboratory of High-Temperature Structural Materials and Coatings Technology Ministry of Industry and Information TechnologyBeijing 100191China

γ’+β Binary-phase Ni-Al coatings were prepared on second-generation single-crystal superalloy Rene N5(N5) substrates by electron beam physical vapor deposition.Inter-diffusion behavior between coatings and substrates at 1100℃ and its effects on microstructure stability of the substrates were investigated.A 3-μm-thick substrate diffusion zone(SDZ) layer forms beneath the coating/substrate interface after 5-h heat treatment.The SDZ layer is composed of γ’-Ni_(3) Al phases and needle-like precipitates growing along(100)(110) or(100) direction.After100-h annealing,the thickness of the SDZ layer increases to~17 μm,much lower than that of the single β-NiAl-coated substrate,while keeping single-crystal microstructure.

关键词： Ni-Al coating EB-PVD Single-crystal superalloy Inter-diffusion Microstructure stability

Effect of trace Ce on high-temperature oxidation behavior of an Al-Sicoated Ni-based single crystal superalloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2019年第1期26卷 78-83页

作者： Xiao-juan Pang Shu-suo Li Lu Qin Yan-ling Pei sheng-kai gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China

Ni-based single crystal superalloy IC21 with different Ce con tents was prepared by screw selection method,and Al-Si coatings were prepared by pack cementation.Cyclic oxidation and transient oxidation were carried out at 1150℃ to investigate the effect of Ce on the high-temperature oxidation behavior of Al-Si coatings.After cyclic oxidation at 1150℃,the addition of trace Ce decreased the mass gain of the Al-Si-coated samples and effectively improved oxidation perform a nee and spallation resistance.In specimens without Ce doping,microstructure examinatio n revealed that bulkyγ-Ni3Al precipitated in oxidized coating because of high Al con sumption,and this finding suggests that Ce inhibits the consumption of Al in the coating during oxidation.Ce slows down the Ininsformation of O-Al2O3 to oc-Al2O3 and improves the adhesion of the oxide scale.

关键词： Single crystal superalloy Trace Ce Al-Si coating Oxidation behavior AlO3