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Isothermal Oxidation Behavior of Dysprosium/S-Doped β-NiAl Alloys at 1200°C

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Journal of Materials Science & Technology 2014年第3期30卷 229-233页

作者： Lu Wang Dongqing Li Jian Chang Hongbo Guo Shengkai Gong Huibin Xu School of Materials Science and engineering Beihang University avic shenyang liming aero-engine group corporation ltd.

A β--NiAI alloy with normal purity, a S-doped and a Dy and S co-doped （Y-NiAI alloys were prepared by arc-melting and their corresponding S contents were less than 20 ×10-6, 33 ×10-6 and 22 × 10-6, respectively. The isothermal oxidation behavior of the alloys at 1200 ℃ was investigated and the extent of S segregation at the scale-alloy interface was determined by scanning Auger microscopy. S-doping had no significant effect on the phase transformation rate from e- to β-Al2O3, while the addition of Dy retarded this process. For the S- doped alloy, scale rumpling occurred only after 2 h thermal exposure and numerous large voids were observed at the scale-alloy interface where S segregated. In contrast to this, the oxide scale formed on the Dy and S co-doped alloy still remained flat even after 50 h isothermal oxidation and only small voids existed at the interface where S segregation was not detected.

关键词： NiAl Dy S Isothermal oxidation Phase transformation Segregation

Complicated hollow turbine blades and surface grain refinement process

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China Foundry 2010年第2期7卷 121-126页

作者： Peng Zhijiang Jia Shuqin Zhang Zehai Liu Yan avic shenyang liming aero-engine （group） corporation ltd Shenyang 110043 shenyang Research Institute of Foundry Shenyang 110022 China

The control of grain size in superalloys is critical in the manufacture of gas turbine *** aim of the present research is to provide the technology for producing complicated hollow turbine blades with fine surface grains and better comprehensive mechanical *** melt superheating treatment and coating the internal surfaces of shell mould using a cobalt aluminate-bearing coating material,the in-uence of cobalt aluminate as inoculant on the surface grain sizes of turbine blade was studied with addition of cobalt aluminate:0,35%,45%-65% and 100% *** the same time,the effects of cooling circumstances of the blades on surface grain sizes were also experimented under the same addition of cobalt *** results showed that the melt superheating treatment plays a significant role in the grain size and carbide morphology;and fine surface grains were obtained when the internal surfaces of shell mould were coated using cobalt aluminate *** the addition of cobalt aluminate in coating is between 45%-65%,and the melt is poured into preheated shell moulds with fine silica sand as backing sand,the blades satisfied the surface grain size requirement is over 90%.In addition,comparisons of the surface grain size and the mechanical properties were also conducted between home-made and foreign-made blades.

关键词： complicated hollow turbine blades K465 alloy surface grain refinement melt superheating treatment

Bearing loads of dual rotor-bearing system under stationary and transient conditions

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Journal of Beijing Institute of Technology 2012年第4期21卷 460-465页

作者：刘树辉王国丽朱清乐周年发陈勇 School of Mechanical engineering Beijing Institute of Technology avic shenyang liming aero-engine (group) corporation ltd

Aimed at aeroengine vibration failure, bearing loads of dual rotor-bearing system caused by unbalance are calculated under stationary and transient conditions. The three-dimensional （3-D） finite element method （FEM） model of dual rotor-bearing system was established. Applying the ro- tor dynamics function of Ansys 12.0, bearing loads were calculated under various unbalance force in stationary condition, and the transient vibration characteristics and the effect of acceleration on bearing loads were discussed. On the basis of simulation results, the influence disciplines of unbal- ance on bearing loads and theoretic reference for reducing bearing loads during start-up were ob- tained.

关键词： dual rotor-bearing system bearing loads rotor dynamics aeroengine

Cyclic oxidation behavior of β-NiAlDy alloys containing varying aluminum content at 1200℃

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Progress in Natural Science:Materials International 2012年第4期22卷 311-317页

作者： Dongqing Li Lu Wang Hui Peng Xiaoyu Zhao Hongbo Guo Shengkai Gong School of Materials Science and engineering Beihang University shenyang liming aero-engine group corporation ltd. AVICShenyang 110043China

β-NiAlDy cast alloys containing varying aluminum content were prepared by arc-melting. The microstructures and cyclic oxidation behavior of the alloys at 1200 ℃ were investigated. Grain refinement was achieved by increasing aluminum content in the alloy, which is beneficial to selective oxidation. The Ni-55Al-0.1Dy alloy showed excellent cyclic oxidation resistance due to the formation of a continuous, dense and slow-growing oxide scale. In contrast to this, severe internal oxidation as well as large void formation at the scale/alloy interface occurred in the Ni-45Al-0.1Dy alloy. The aluminum content dependence of the reactive element effects in β-NiAlDy was established that Dy doping strengthened the scale/alloy interface by pegging mechanism in high-aluminum alloys but accelerated internal oxidation in low-aluminum alloys during high-temperature exposure.

关键词： β-NiAl Reactive elements Dysprosium Aluminum content High-temperature oxidation

Local deformation and processing maps of Ti-24Al-17Nb-0.5Mo alloy

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Acta Metallurgica Sinica(English Letters) 2012年第2期25卷 95-101页

作者： Yong WANG Bin LU Rui YANG Xiaodong HAN Ping REN Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Linyi Academy of Technology Cooperation and Application Linyi 276001 China avic shenyang liming aero-engine （group） corporation ltd Shenyang 110043 China

The processing maps were used to identify the optimal forging parameters of Ti-24A1- 17Nb-0.5Mo alloy by evaluating the flow data according to the DMM model. The actual local strain rate and strain distribution in the samples were obtained by finite element calculations. The local microstructures of the deformed samples were related to the local deformation parameters and correlated with the processing maps at 0.3, 0.4, 0.5 and 0.6 of logarithmic strain. Flow regimes predicted by DMM analysis were then correlated with the local microstructural observations. Five domains of efficient coefficient could be distinguished. Unstable regions were microstructurally related to shear band formation within the （~2~B2 phase deformation field, and to flow localiza- tion at grain boundaries of B2 phase in the near B2 phase deformation field. Stable flow regimes were shown to be associated with dynamic globularization of the plate- like a2 in the a2＋B2 phase deformation zone, and with dynamic recrystallization of B2 in the near B2 phase deformation zone.

关键词： Processing map Local deformation Ti-24Al-17Nb-0.5Mo alloy Hot deformation

Evolution of Grain Selection in Spiral Selector during Directional Solidification of Nickel-base Superalloys

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Journal of Materials Science & Technology 2011年第2期27卷 118-126页

作者： Xiangbin Meng Jinguo Li Tao Jin Xiaofeng Sun Changbo Sun Zhuangqi Hu Institute of Metal Research Chinese Academy of SciencesShenyang 00China Graduate School of Chinese Academy of Sciences Beijing 000China shenyang liming aero-engine(group) corporation ltd. Aviation Industry Corporation of China(AVIC)Shenyang 110043China

The process of grain selection in the spiral selector was investigated by both a ProCAST simulation based on a cellular automaton finite element（CAFE） model and experimental *** results show that the height of starter block,the spiral diameter and initial angle play an important role in grain *** dimension of selector should be maintained in a stable range to optimize the grain orientation and select a single crystal efficiently.A selector which can efficiently select a single crystal had been successfully *** orientation fluctuation in the spiral part was also studied by means of the variation of thermal condition.

关键词： Ni-base single crystal superalloys Grain selection Directional solidification

Fatigue Life Prediction of Horizontal Press Frame Based on Statistical Probability and Its Redesign

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Journal of Harbin Institute of Technology(New Series) 2014年第2期21卷 43-49页

作者： Wei-Wei Zhang Xiao-Song Wang Bo Yang Shi-Jian Yuan School of Materials Science and engineering Harbin Institute of Technology avic shenyang liming aero-engine group Co. ltd

Horizontal press as an important part of hydro-forming machine is used to output the horizontal force to keep the high internal pressure during tube hydro-forming. However,the horizontal press frame is usually mounted on the press bed and not pre-stressed. Meanwhile it will be subjected to the reaction force caused by liquid pressure. Stresses are concentrated severely on the assemble region due to deformation,and total fatigue life will decrease. In order to predict the total fatigue life of the frame,the simulations are used firstly to determine to stress concentration region,and then strain gauge measurements are carried out under different loads. Next,the methods of statistical probability are conducted to calculate the fatigue life based on long-term load history. Finally a structure with the considerable longer fatigue life is redesigned.

关键词： horizontal press statistical probability fatigue life prediction structure redesign

Experimental and Numerical Research on Deformation Behavior of Thin-Walled and Large Expansion Ratio Guide Vane Liner in Hydroforming Process

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Journal of Harbin Institute of Technology(New Series) 2015年第4期22卷 1-9页

作者： Pengzhi Cheng Lihui Lang Yulong Ge Shangwen Ruan Xinmin Duan Tianwei Shao School of Mechanical engineering & Automation Beihang University avic shenyang liming aero-engine (group) Co. Ltd.

Some tube hydroforming process tests and further research work were conducted to manufacture hollow guide vane liners( made of super alloy GH3030).The relative thickness( t0/ OD) of the tubular blank is approximately 0. 01,and the maximum expansion ratio( Dmax/ OD) of the needed part is more than 40%,and the length to diameter ratio of the expansion regionis more than 3. 0. It is very hard to manufacture this kind of ultra-thin-wall,curved axis and large expansion ratio tubular part without fracture and wrinkles. The success of the process is highly dependent on useful wrinkles with appropriate internal pressure and axial feeding. A simplified finite element model and a theoretical model are used for detecting the deformation behavior and forming laws. Further study results demonstrate that the useful wrinkles do not appear at the same time and middle-wrinkles need bigger axial force than tube-end-wrinkles and feeding-wrinkles. The wrinkles can transfer bigger axial force after its wave peak has come into contact with the die inner surface. The thickness thinning rate of the element at the peak is bigger than that at the trough. With the increase of the axial and hoop stress ratio,the critical buckling stress also increases. Microstructure examination results show that the grain size in the maximum thinning zone has been stretched and refined after the large deformation and annealing *** process is feasible and the finished part is qualified.

关键词： tube hydroforming super alloy ultra-thin-wall large expansion ratio useful wrinkle plastic buckling critical buckling stress

Effect of Solution Treatment on the Microstructure and Mechanical Properties of Sand-Cast Mg–9Gd–4Y–0.5Zr Alloy

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Acta Metallurgica Sinica(English Letters) 2018年第2期31卷 189-198页

作者： Jing-Li Li Na Zhang Xiao-Xuan Wang Di Wu Rong-Shi Chen The group of Magnesium Alloys and Their Applications Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Materials Science and engineering University of Science and Technology of China Hefei 230026 China avic shenyang liming aero--engine group corporation Shenyang 110043 China

Sand-cast Mg–9Gd–4Y–0.5 Zr（wt%） alloy was solution-treated at 500–565 ℃ in the time range of 0.5–30 h in air or vacuum to investigate its microstructure evolution and mechanical properties. The results showed that solution treatment temperature had a significant influence on the dissolving rate of eutectic phase and grain growth. Taken both of them into consideration, 510–520 ℃ was considered to be the optimum solution treatment temperature range for this *** should be noted that the trace（0.4–0.9 vol%） and insoluble cuboid-shaped phase precipitated during solution treatment was identified to be YH2, of which the hydrogen was thought to come from both the melting and solution heating *** addition, the 3D morphology and dissolving process of Mg24（Gd,Y）5 eutectic phases in the as-cast alloy were also discussed via in-situ observation under X-ray tomography.

关键词： Mg-Gd-Y-Zr alloy Solution treatment Microstructure Rare-earth hydride