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Effect of Heat Treatment on the Microstructure of Multiphase nial-based Alloy

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Journal of Materials Science & Technology 2008年第2期24卷 245-250页

作者： Yi XIE Lanzhang ZHOU Jianting GUO Hengqiang YE Superalloys Division Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

The alloy Ni-Al26.6-Cr13.4-Co8.1-Ti4.3-W1.3-Mo0.9 （at. pct） was fabricated from superalloy K44 and Al element using vacuum induction and casting technique. Investigations to this alloy reveal that a new phase Cr3Ni2 possessing low melting point and poor ductility is formed, which is distributed as a network along NiAI matrix grain boundaries. Subsequent different solution and aging treatments are carried out and lead to microstructural changes to various extents. Rapid cooling after solution at 1250℃ for 20 h gives rise to macrocracks in the specimen while slow cooling after the same treatment results in the formation of spheric α-Cr solid solution and needle-like Ni3Al phase, which are embedded in nial matrix. It is comfirmed that aging treatments initiate lath-shaped Ni3Al phase and pearl-shaped α-Cr phase to precipitate from the nial matrix, which own orientation relationships with these precipitates.

关键词： nial Intermetallics Microstructure Solution and aging treatments

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

SIMULATIVE INVESTIGATION OF GRAIN BOUNDARIES IN nial ALLOY

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中国有色金属学会会刊：英文版 1999年第1期9卷 107-112页

作者： Liu, Zhenyun Huang, Baiyun Lin, Dongliang Central South Univ of Technology Changsha China

１ＩＮＴＲＯＤＵＣＴＩＯＮＮｉＡｌａｌｏｙｗｉｔｈａＢ２ｓｔｒｕｃｔｕｒｅｈａｓａｈｉｇｈｍｅｌｔｐｏｉｎｔ（１６３８℃），ｌｏｗｄｅｎｓｉｔｙ（５．８６ｇ／ｃｍ３），ｈｉｇｈｍｏｄｕｌｅ（２９４ＧＰａ）ａｎｄｈｉｇ... 详细信息

１ＩＮＴＲＯＤＵＣＴＩＯＮＮｉＡｌａｌｏｙｗｉｔｈａＢ２ｓｔｒｕｃｔｕｒｅｈａｓａｈｉｇｈｍｅｌｔｐｏｉｎｔ（１６３８℃），ｌｏｗｄｅｎｓｉｔｙ（５．８６ｇ／ｃｍ３），ｈｉｇｈｍｏｄｕｌｅ（２９４ＧＰａ）ａｎｄｈｉｇｈｈｅａｔｃｏｎｄｕｃｔｉｏｎｃｏ...

关键词： nial grain boundary structure computer simulation

First-principles investigation on ideal strength of B2 nial and NiTi alloys

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Chinese Physics B 2020年第3期29卷 335-339页

作者： Chun-Yao Zhang Fu-Yang Tian Xiao-Dong Ni Institute for Applied Physics University of Science and Technology BeijingBeijing 100083China

For B2 nial and NiTi intermetallic compounds, the ideal stress–strain image is lack from the perspective of elastic constants. We use first-principles calculation to investigate the ideal strength and elastic behavior under the tensile and shear loads. The relation between the ideal strength and elastic constants is found. The uniaxial tension of nial and NiTi along crystal direction leads to the change from tetragonal path to orthogonal path, which is driven by the vanishing of the shear constant C(66). The shear failure under {110}{111} shear deformation occurring in process of tension may result in a small ideal tensile strength(~ 2 GPa) for NiTi. The unlikeness in the ideal strength of Ni Al and Ni Ti alloys is discussed based on the charge density difference.

关键词： ideal strength stress–strain elastic constants first-principles calculation nial and NiTi charge density difference

Effect of Wetting and nial_2O_4 Spinel Formation on the Bonding between Al_2O_3 and Ni

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Journal of Materials Science & Technology 1996年第6期12卷 421-426页

作者： Xudong SUN and J.A. Yeomans (Dept. of Materials Science and Engineering, University of Surrey Guildford, Surrey GU2 5XH, UK (To whom correspondence should be addressed Present address: Dept. of Materials Science and Engineering, Northeastern University, Dept. of Materials Science and Engineering University of Surrey Guildford Surrey GU2 5XH United Kingdom Dept. of Materials Science and Engineering Northeastern University Shenyang 110006 China

Al2O3-Ni interface formed under vacuum condition is non-wetting and weak. Severe instantaneous intedecial reaction (i.e. wetting) at the Al2O3-Ni interface promoted by oxygen can create a strengthened interface. The nial2O4 spinel-Ni intedece is weak and growth of the spinel interphase is detrimental to the Al2O3-Ni intedecial bonding. A proper control of the oxygen partial pressure can achieve wetting while avoiding the existence of spinel at the interface, producing stronger interfaces by both mechanical interlocking and more intimate chemical bonding in an Al2O3-20 vol pct Ni composite.

关键词： nial Effect of Wetting and nial2O4 Spinel Formation on the Bonding between Al2O3 and Ni IFI Figure

BDT and Creep Behaviors of nial-25 *** Cr Alloy at Various Temperatures

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Journal of Materials Science & Technology 2005年第5期21卷 641-646页

作者： Guangye ZHANG, Xinghao DU, Jianting GUO+ and Hengqiang YEInstitute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Brittle-to-ductile transition （BDT） behavior and creep behavior of extruded nial-25Cr alloy at elevated temperatures were investigated. The results reveal that the alloy exhibits obvious BDT behavior with the increase in temperature and BDT temperature （BDTT） is sensitive to initial strain rate. When the initial strain rate increases by two orders of magnitude, BDTT has an increase of approximate 80 K. The creep data in the temperature range of 1073～1123 K reveal two distinct regions of creep behavior in this material. At lower temperature, the creep characteristics are consistent with structural controlled creep process where creep deformation is controlled by dislocation climb. At higher temperature, the creep characteristics are consistent with mobility-controlled deformation where viscous glide of dislocations controls creep. The apparent activation energy determined by creep in both regions exceeds the value for lattice self-diffusion in nial by a considerable amount. This can be explained in terms of the simultaneous deformation of second phase particles （γ′-Ni3Al and a-Cr phase） along nial matrix during creep.

关键词： nial Intermetallics Mechanical properties Brittle-to-ductile transition Creep

Investigation of Subboundaries Evolution in Superplastically Deformed nial by Positron Lifetime

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Journal of Materials Science & Technology 2003年第4期19卷 373-375页

作者： XinghaoDU JiantingGUO BideZHOU LiangyueXIONG DepartmentofSuperalloys InstituteofMetalResearchChineseAcademyofSciencesShenyang110016China SchoolofMaterialSciencesandEngineering HarbinInstituteofTechnologyHarbin150001China

In order to study the subboundaries evolution in superplastically deformed nial, the positron lifetime change during superplastic deformation process was measured. It is shown that the superplastic deformation of nial has not influence on its T2, the newly recrystallized grain boundaries formed during entire superplastic deformation process belong to the calegory of subboundaries and have not contribution to the superplastic strain.

关键词： nial Positron lifetime Superplasticity Boundaries

ATOMISTIC SIMULATION OF POINT DEFECTS IN nial ALLOY

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中国有色金属学会会刊：英文版 1997年第2期7卷 129-132页

作者： Liu, Zhenyun Lin, Dongliang Chen, Da Shanghai Jiao Tong Univ Shanghai China

ＡＴＯＭＩＳＴＩＣＳＩＭＵＬＡＴＩＯＮＯＦＰＯＩＮＴＤＥＦＥＣＴＳＩＮＮｉＡｌＡＬＬＯＹ①ＬｉｕＺｈｅｎｙｕｎ，ＬｉｎＤｏｎｇｌｉａｎｇ，ＣｈｅｎＤａＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅ，Ｓｈａｎ... 详细信息

ＡＴＯＭＩＳＴＩＣＳＩＭＵＬＡＴＩＯＮＯＦＰＯＩＮＴＤＥＦＥＣＴＳＩＮＮｉＡｌＡＬＬＯＹ①ＬｉｕＺｈｅｎｙｕｎ，ＬｉｎＤｏｎｇｌｉａｎｇ，ＣｈｅｎＤａＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅ，ＳｈａｎｇｈａｉＪｉａｏＴｏｎｇＵｎｉｖｅ...

关键词： nial intermetallic point defects computer simulation

Preliminary Investigation of nial-TiB_2 Composite Prepared by Reaction Milling

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Journal of Materials Science & Technology 1999年第5期15卷 427-430页

作者： Lanzhang ZHOU and Jianting GUO(Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China To whom correspondence should be addressedE-mail: lzz@imr. ac .cn ) Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

Reaction-milled nial-TiB2 composite was fabricated by mechanical alloying elemental powders and hot pressing. TiB2 particles are distributed mostly in grain boundaries of the matrix. The compressive strain to failure of the composite at RT is about twice that of cast nial. The compressive yield stress at high temperatures is about 4.5 times higher than that of extruded nial, and is also much stronger than XD nial-TiB2 composites. Deformation behavior between 1000~1100℃ with different strain rates has been investigated

关键词： TiB nial Preliminary Investigation of nial-TiB2 Composite Prepared by Reaction Milling