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Oxidation Performance and Interdiffusion Behaviour of two MCrAlY Coatings on a fourth-Generation Single-Crystal Superalloy

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Acta Metallurgica Sinica(English Letters) 2022年第4期35卷 679-692页

作者： K.J.Tan J.J.Liang x.G.Wang x.P.Tao J.Gong C.sun Y.Z.Zhou x.f.sun Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

The oxidation behaviour of a fourth-generation single-crystal superalloy without coating and with two types of MCrAlY coatings at 1140℃was *** results showed that both coatings greatly improved the oxidation resistance of the superalloy,and the addition of Hf further improved the oxidation resistance by pinning the oxide layer into the *** and after oxidation,obvious Cr and Al interdiffusion was *** Cr diffusion induces the precipitation of a topologically close-packed phase,while the diffusion of Al affects the structure of theγ/γ’phase,the solubility of refractory elements,and the formation of an interdiffusion zone.

关键词： Superalloys Metal coatings Oxidation Electron probe microanalyser(EPMA) Element diffusion

Sample selection for models to represent ceramic cores fabricated by stereolithography three-dimensional printing

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Journal of Materials Science & Technology 2022年第26期121卷 117-123页

作者： x.L.An J.J.Liang J.G.Li J.W.Chen Y.Z.Zhou x.f.sun School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Space Manufacturing Technology(CAS Key Lab) Beijing 100094China

Ceramic cores with good chemical stability and moderate mechanical properties near casting temperatures of 1550℃ for example are used for the manufacturing of internal structures of hollow blades,requiring complex structures and high precision[1–3].However,traditional preparation method based on investment casting is tedious,requiring not only long production cycles but also high cost[4].

关键词： investment printing ceramic

Effect of post-bond heat treatment on the microstructure and high temperature mechanical property of a TLP bonded γ'-strengthened co-based single crystal superalloy

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Journal of Materials Science & Technology 2021年第21期80卷 244-258页

作者： S.Y.Wang Y.sun C.Y.Cui x.f.sun Y.Z Zhou Y.M.Ma H.L.An Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China Harbin Welding Institute China Academy of Machinery Science and TechnologyHarbin 150028China

Post-bond heat treatment(PBHT) applied to a transient liquid phase(TLP) bonding joint is an effective approach to remove the brittle borides and improve its ***,we proposed two types of PBHT strategies to obtain a TLP bonded γ'-strengthened Co-based single crystal superalloy,and the microstructural characteristics and tensile properties of the two heat treated joints were compared to identify the optimal PBHT *** evolution of the brittle boride in the joint after the PBHT was studied by using in-situ *** experimental results allowed to provide a theoretic model to quantitatively evaluate the distribution of the brittle phase after the optimal PBHT and analyze the joint fractures to understand the failure *** obtained results revealed that a post-bond solid solution treatment performed to the joint at a high temperature(over 1275℃) could decrease the area fraction of the boride from 7.2 % to 1.4 % and increase the elongation from 1.9 % to 7.8 %.This work emphasizes the relevance of solid solution temperature when a PBHT strategy is applied.

关键词： Transient liquid phase(TLP) γ'-strengthened co-based single crystal superalloy Heat treatment sequence Brittle boride Tensile property

Stress-rupture behavior of a Re-containing Ni-base single crystal superalloy at high temperatures

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Journal of Materials Science & Technology 2023年第32期163卷 237-244页

作者： G.L.Wang D.Q.Qi J.L.Liu J.D.Liu J.G.Li Y.Z.Zhou x.f.sun Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

A Re-containing Ni-base single crystal superalloy was used to investigate the elementary processes associated with stress-rupture behavior at different temperatures where theγʹrafting *** 900°C,the rupture behavior is mainly determined by the multiplication of dislocations within the wideningγchannels,which is closely linked with the propagation of microcracks along the inherentγ/γʹ*** rapid formation of lamellaγ/γʹraft structure,along with the developed-well interfacial dislocation networks,and its elastic instability are primarily responsible for the rupture behavior at 1100°*** is a clear curvature tendency in the Larson-Miller plot of stress-rupture lifetime in relation to stress at high *** indicates that the influence extent ofγʹrafting on stress-rupture behavior is sensitive to the acting conditions of temperature and stress.

关键词： Ni-based single crystal superalloy Re effect γʹrafting Stress-rupture behavior Elementary process Larson-Miller plot

Effects of Alumina on Cristobalite Crystallization and Properties of Silica-Based Ceramic Cores

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Journal of Materials Science & Technology 2017年第2期33卷 204-209页

作者： J.J.Liang Q.H.Lin x.Zhang T.Jin Y.Z.Zhou x.f.sun B.G.Choi I.S.Kim J.H.Do C.Y.Jo Institute of Metal Research Chinese Academy of SciencesShenyang 110016China Korea Institute of Materials Science Changwon 642-831Republic of Korea

In this work, the influences of alumina addition on cristobalite crystallization and properties of injec- tion molded silica-based ceramic cores were investigated. x-ray diffraction （xRD） was used to characterize phase transformations in the samples, and the xRD result indicated that the addition of alumina pro- moted crystallization of fused silica during sintering at 1180-1220 ℃ and thus increases the amount of cristobalite. The increased amount of cristobalite as well as alumina addition led to much more thermal dilation due to their higher coefficients of thermal expansion than that of fused silica. The flexural strengths at room temperature and 1500 ~C were tested, and it was shown that alumina addition could not affect room temperature strength, but decreased the flexural strength at 1500 ℃. In addition, deflection resis- tance during heating to high temperatures was investigated, and the result indicated that alumina addition speeded up high temperature softening of the samples. xRD and scanning electron microscopy equipped with energy dispersive spectrometry （SEMJEDS） analysis suggested that this softening behavior was related with viscous flow sintering which could be accelerated by the reaction of alumina and silica with a product of mullite.

关键词： Silica-based ceramic cores Alumina Cristobalite crystallization Properties

动态增强MRI生物标志物预测原发性中枢神经系统淋巴瘤的化疗疗效和生存期

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国际医学放射学杂志 2021年第3期44卷 368-368页

作者： f.fu x.f.sun Y.Y.Li Y.B.Liu Y.Shan N.Ji 贾兆刚

摘要目的评价动态增强MR(IDCE-MRI)在预测原发性中枢神经系统淋巴瘤(PCNSL)病人化疗疗效和临床结局中的作用。方法前瞻性纳入2016—2019年期间共56例病

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BEHAVIOR Of SHORT fATIGUE CRACKS AT BLUNT NOTCHES IN A MEDIUM CARBON STEEL

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Acta Metallurgica Sinica(English Letters) 1997年第5期10卷 430-436页

作者： Wu, Z.x. sun, x.f. Southwest Jiaotong Univ Chengdu China

The behavior of part-through and through short cracks in single edge blunt notched specimens of a medium carbon steel was investigated by a replication method. It is found that the fatigue failure of these notched specimens is caused mainly by the growth of short surface cracks originating from the surface of notch root. More than 70% of the fatigue life is spent in the regimes in which short surface cracks initiate and propagate as part-through cracks before joining up to form a single through-thickness crack. The effect of original crack profile which is formed through the coalescence of multiple part-through cracks is the main reason causing the 'anomalous' propagation behavior of the through-thickness crack in its early stage.

关键词： Carbon steel Crack initiation Crack propagation fatigue of materials fracture mechanics Surfaces

COMPARISON Of SURfACE PROPERTIES Of Ti-6Al-4V COATED WITH TITANIUM NITRIDE, TiN+TiC+Ti(C,N)/DLC, TiN/DLC AND TiC/DLC fILMS BY PLASMA-BASED ION IMPLANTATION

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Acta Metallurgica Sinica(English Letters) 2000年第4期13卷 967-973页

作者： Ji, H.B. xia, L.f. Ma, x.x. sun, Y. sun, M.R. Harbin Inst of Technology Harbin China

The surface properties of Ti-6Al-4V alloy coated with titanium nitride, TiN+TiC+Ti(C,N)/DLC (diamond like carbon), TiN/DLC and TiC/DLC films by plasma-based ion implantation (PBII) with nitrogen, PBII with nitrogen then acetylene, PBII with nitrogen then glow discharge deposition with acetylene plus hydrogen and PBII with acetylene then glow discharge deposition with acetylene plus hydrogen respectively were studied. The corresponding films are found getting dimmer, showing light gold or gold, smoky color (uneven), light red in black (uneven), and graphite black separately. The corresponding film resistivities are given. Antioxidation ability of the titanium nitride film is poor, while the existence of carbon (or carbide) improves the antioxidation ability of the films. Having undergone excellent intermediate transitional region of nitrogen and carbon implantation, the top DLC layer of the TiN+TiC+Ti(C,N)/DLC multilayer are formed after the carbon implantation has the best adhesion with the substrate among all the multilayers. Although microhardness of the samples increases in the order of coatings of titanium nitride, TiN/DLC, TiN+TiC+Ti(C,N)/DLC and TiC/DLC, the TiN/DLC and TiC/DLC multilayers have greater brittleness as compared with other films.

关键词： Titanium alloys Titanium nitride Plasmas Ion implantation Microhardness Surface properties

xPS INVESTIGATION Of NITROGEN IONS IMPLANTED INTO ALUMINUM ALLOY BY PLASMA BASED ION IMPLANTATION

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 771-776页

作者： Zhan, Z.J. Ma, x.x. xia, L.f. sun, Y. Harbin Inst of Technology Harbin China

Aluminum alloy 2024 has been implanted with nitrogen ions at various doses by plasma based ion implantation. The introduction of energetic ions causes structural change within the near surface region of the solid. The samples have been characterized by x-ray Photoelectron Spectroscopy at various depths. The chemical states of Al and N were identified by deconvolution of the recorded xPS spectra. After plasma based ion implanted nitrogen into aluminum, not only the AlN precipitates but also super saturated solution of nitrogen forms. The presence of aluminum in different chemical states is corresponding to Al, AlN and Al2O3. The majority of nitrogen is in the form of the supersaturated solution. With the increase of nitrogen dose, the amount of AlN precipitates increases.

关键词： Aluminum compounds Ion implantation Nitrides Nitrogen Plasma devices Wear of materials