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Precipitation of multi-type nano-quasicrystals in a Mg-zn-Y alloy

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Journal of Magnesium and Alloys 2024年第3期12卷 997-1008页

作者： W.z.Wang X.z.zhou L.F.zhang H.Q.Ye z.Q.Yang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of ScienceShenyang 110016China Ji Hua Laboratory Foshan 528251China Foshan University Foshan 528231China

Mg-6zn-1Y(at.%)ribbons with strengthening precipitates of multi-type nanoquasicrystals were prepared by melt-spinning followed by aging *** evolution of the rapidly solidified ribbons during isothermal aging was comprehensively studied using various electron microscopy *** new kinds of decagonal quasicrystals were formed in aged ribbons,in addition to precipitation of nanometer icosahedral ***-resolution observations reveal that both decagonal quasicrystals can be modeled by quasiperiodic tiling with decagonal clusters of 2.5 nm in diameter,but overlap of neighboring clusters in both decagonal quasicrystals is different from the Gummelt model observed in other quasicrystals.A shell composed of complex Laves Mg-zn domains was formed surrounding each decagonal quasicrystal precipitate upon prolonged *** addition,all kinds of nanoprecipitates exhibit excellent structure and size stability at 573 *** findings may have implications for not only fundamental studies about quasicrystals,but also microstructural manipulation of high-performance Mg alloys.

关键词： Quasicrystal Mg alloys Rapid solidification Scanning-transmission electron microscopy.

Dual Topological Features of Weyl Semimetallic Phases in Tetradymite BiSbTe_(3)

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Chinese Physics Letters 2021年第7期38卷 69-73页

作者： z.z.zhou H.J.Liu G.Y.Wang R.Wang X.Y.zhou Center for Quantum Materials and Devices College of PhysicsChongqing UniversityChongqing 401331China Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education and School of Physics and TechnologyWuhan UniversityWuhan 430072China Chongqing Institute of Green and Intelligent Technology Chinese Academy of ScienceChongqing 400714China

Based on first-principles calculations and symmetry arguments,we reveal that the non-centrosymmetric ternary tetradymite BiSbTe_(3) possesses exotic dual topological features of Weyl semimetallic phases with z_(2) index(1:000).The results show that the helical Dirac-type surface states protected by the time-reversal symmetry are present in the vicinity of the Brillouin zone center,which is consistent with the experimental ***,we show that four pairs of Weyl points reside exactly at the Fermi level,which are guaranteed to be located on high-symmetry planes due to mirror *** helical surface states and the projected Weyl nodes are well separated in the momentum space,facilitating their observations in *** work not only uncovers a unique quantum phenomenon with dual topological features in the tetradymite family but also paves a fascinating avenue for exploring the coexistence of multi-topological states with wide applications.

关键词： metallic symmetry topological

High-temperature fatigue strength of grain boundaries with different misorientations in nickel-based superalloy bicrystals

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Journal of Materials Science & Technology 2023年第23期154卷 94-106页

作者： D.F.Shi z.J.zhang Y.H.Yang Y.z.zhou R.Liu P.zhang z.F.zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Materials Science and Engineering University of Science and Technology of China Shenyang 110016 China

Nickel-based single-crystal superalloys are widely used in the manufacture of aeroengine turbine vanes for their excellent high-temperature performance. Low-angle grain boundaries (LAGBs) will be generated inevitably during their manufacture, which are often characterized by grain boundary misorientation (GBM) and will weaken the mechanical properties of superalloys. However, the relationship between GBM and the fatigue properties of superalloys at elevated temperatures has seldom been investigated due to the difficulty in the sample preparation and experiment process. Based on six kinds of bicrystals with different tilt LAGBs made by a second-generation single-crystal superalloy, the effects of misorientation on the grain boundary microstructure and fatigue properties (980 °C) of superalloys were studied systematically in this work. It is found that, with the increase of GBM, the GB precipitates combined with the cast micropores increase monotonically, accordingly both the fatigue life and fatigue strength decrease successively. Fatigue fracture observations show that the cracks of all the bicrystals initiated from the cast micropores at GBs, and then propagated along the GBs. Therefore, the coupling effect of cast micropores and GBM on the fatigue damage mechanisms of the bicrystals are evaluated according to their hindering degrees on the piled-up dislocations. Combining with a hysteresis energy model, a quantitative fatigue strength prediction model of superalloys is established and is well verified by abundant experimental data. This study could provide guidance for fatigue performance prediction and structural design of superalloys.

关键词： Superalloys Bicrystals Grain boundary misorientation Fatigue strength Fatigue crack

Development and application of functional gene arrays for microbial community analysis

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中国有色金属学会会刊：英文版 2008年第6期18卷 1319-1327页

作者： z. L. HE J. D. VAN NOSTRAND L.Y. WU J. z. zhou Institute for Environmental Genomics Department of Botany and Microbiology University of Oklahoma Norman OK 73019 USA

功能的基因标记能关于功能的基因差异和微生物引起的社区的潜在的活动提供重要信息。尽管 microarray 技术成功地被使用了为纯文化学习基因表示，简单、人工的微生物引起的社区，改编如此的一种技术分析复杂微生物引起的社区仍然以设计... 详细信息

功能的基因标记能关于功能的基因差异和微生物引起的社区的潜在的活动提供重要信息。尽管 microarray 技术成功地被使用了为纯文化学习基因表示，简单、人工的微生物引起的社区，改编如此的一种技术分析复杂微生物引起的社区仍然以设计，样品准备，和数据分析提出很多挑战。这个工作集中于功能的基因数组(FGA ) 的开发和应用程序为微生物引起的社区研究指向关键功能的基因标记。一些与 FGA 有关明确地给问题调音，例如 oligonucleotide 探查设计， nucleic 酸抽取和纯化，数据分析，特性，敏感，和量的能力详细被讨论。最近的研究证明了 FGA 能从许多自然环境关于微生物引起的社区提供特定、敏感、潜在地量的信息并且控制生态系统。这种技术被期望革命化微生物引起的社区的分析，并且连接微生物引起的结构到生态系统工作。

关键词：微数列应用函数基因标记微生物种群

MORPHOLOGY OF AMORPHOUS SILICA DURING ALUMINUM REACTIVE PENETRATION

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Acta Metallurgica Sinica(English Letters) 2000年第4期13卷 944-948页

作者： zhou, z. Gan, Q.S. Ding, P.D. Chongqing Univ Chongqing China

The reduction of volume of silica glass during aluminum reactive penetration was observed experimentally. The liquid aluminum infiltrates easily into the cavities while the released silicon is solved in the liquid aluminum, and Al/Al2O3 composites could be obtained. The experimental results show that Al/Al2O3 composites can be transformed into Al2O3 grains by oxygen in the cavities of Al/Al2O3 composites during the longer penetration treatment. The formation of alumina is a sintering process, in which liquid aluminum, particulate alumina and oxygen play an important role. The transformtion process has shown that there is a relationship of σAl2O3-Al2O3 2O3-Al, where σAl2O3-Al2O3 is the grain boundary energy of alumina, and σAl2O3-Al is the interface energy between aluminum and alumina. The formation temperature by aluminum reactive penetration is much lower than that by sintering.

关键词： Alumina Aluminum Metallic matrix composites Morphology Silica

CREEP BEHAVIOR MODELING OF UDIMET 720Li SUPERALLOY

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Acta Metallurgica Sinica(English Letters) 2005年第1期18卷 65-73页

作者： V.Lupinc M.Maldini L.z.zhou J.T.Guo Isfitutoperl＇EnergedcaeperleInterfasi ConsigfioNazionaledelleRicercheCNR-IENI20125MilanItaly Isfitutoperl＇EnergedcaeperleInterfasi ConsigfioNazionaledelleRicercheCNR-IENI20125MilanItaly／／InstituteofMetalResearchTheChineseAcademyofSciencesShenyang110016China InstituteofMetalResearch TheChineseAcademyofSciencesShenyang110016China

Constant load creep tests on isothermally forged Udimet 720Li, an advanced superalloy for gas turbine disc application, were run in the stress/temperature field 900-450MPa/650-700 ℃ producing rupture times in the 20-5000h range. The creep curves have shown a predominant accelerating creep stage, that has been described by the following equation: where ε min depends on stress and temperature, while parameter C depends mainly on stress. A strain dependent damage, defined by the parameter C, causes the accelerating creep stage at stresses lower than 750MPa, whilst its contribution to the creep strain acceleration is less important at higher stresses. The model rationalizes the different behaviors at high and low stress and has been validated with variable stress and temperature creep behavior.

关键词： Udimet 720Li creep creep curve shape creep damage

STABILITY OF MICROSTRUCTURES DURING COOLING PROCESSES OF Al LIQUID METAL

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中国有色金属学会会刊：英文版 1998年第4期8卷 2-7页

作者： Liu, RS Li, JY zhou, z Dong, KJ Peng, P Xie, Q zheng, CX Hunan Univ Dept Phys Changsha 410012 Peoples R China Hunan Univ Dept Chem Changsha 410012 Peoples R China

１ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｗｅｌｋｎｏｗｎｔｈａｔｔｈｅｍａｃｒｏｓｃｏｐｉｃｐｒｏｐｅｒｔｉｅｓｏｆｍｅｔａｌｓａｎｄａｌｏｙｓａｒｅｍａｉｎｌｙｄｅｔｅｒｍｉｎｅｄｂｙｔｈｅｉｒｍｉｃｒｏｓｔｒｕｃｔｕ... 详细信息

１ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｗｅｌｋｎｏｗｎｔｈａｔｔｈｅｍａｃｒｏｓｃｏｐｉｃｐｒｏｐｅｒｔｉｅｓｏｆｍｅｔａｌｓａｎｄａｌｏｙｓａｒｅｍａｉｎｌｙｄｅｔｅｒｍｉｎｅｄｂｙｔｈｅｉｒｍｉｃｒｏｓｔｒｕｃｔｕｒｅｓ，ａｎｄｔｈｅｍｉｃｒｏｓｔ...

关键词： stability microstructure liquid metal rapid cooling computer simulation

EFFECT　OF　IRON　ON　FORMATION　OF　MECHANICALLY　ALLOYED　NiAl　ALLOY　AND　ITS　MECHANICAL　PROPERTIES

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Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 515-518页

作者： J.T. Guo L.z. zhou z.G. Liu and W.M. Yin(Institnte of Metal Research,Chinese Academy of Sciences,Shenyang 110015, China) Inst of Metal Research Chinese Acad of Sciences Shenyang China

Ternary Ni-Al-Fe alloys with different Fe-additions have been synthesized by mechan ical *** results show that 5 and 10 at% Fe-additions prolong the milling time prior to the explosive formation of NiAl(Fe) compound, 15 at.% Fe-addition results in the formation of an 'amorphous-like' phase,20 at.% Fe-addition turns the final products to Ni(Al, Fe)supersaturated solid solution with fcc structure,and the increase of Fe-addition can speed up the formation of the solid *** addition of Fe improves the plastic deformation ability of the alloys.

关键词： mechanical alloying NiAl alloy intermetallic compound

Effects of rejuvenation heat treatment on microstructure and creep property of a Ni-based single crystal superalloy

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Journal of Materials Science & Technology 2021年第1期60卷 206-215页

作者： K.J.Tan X.G.Wang J.J.Liang J.Meng Y.z.zhou X.F.Sun Superalloys Division Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Department of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Both surface and internal microstructures of a second-generation Ni-based single crystal(SX) superalloy were studied after creep and rejuvenation heat treatment(RHT).It is indicated that the microstructures,such as the dislocation network,the γ phase and the γ' phase,can be recovered to those after the standard heat treatment(SHT).It is found that RHT affected zone(RAz) formed at the surface is composed of theγ'-free layer,the transition layer and the recrystallization(RX),which are less than 20 μm in depth *** depth of the RAz doesn't affect the properties of the *** morphology of γ' phase at the RAz is related to the composition of the *** average creep life after RHT is close to the average life after *** is concluded that RHT could effectively repair SX parts and increase the total life of the sample after a damage by creep.

关键词： Superalloys Rejuvenation heat treatment Microstructure Creep property