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SUPERPlAStICItY OF A Ni-28.5Al-20.4Fe INtERMEtAllIC AllOY

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Acta Metallurgica Sinica(English letters) 2000年第3期13卷 888-892页

作者： zhou, W.l. guo, j.t. Chen, R.S. zhou, j.Y. Inst of Metal Research Chinese Acad of Sciences Shenyang China

Our previous investigation examined the superplastic behavior of an extruded Ni-28.5Al-20.4Fe alloy. Its tensile properties were determined at temperature from 1123 K to 1323 K and initial strain rates from 1.04×10-2s-1 to 1.04×10-4s-1. A maximum elongation of 233% was obtained at 1123 K and a strain rate of 5.2×10-4s-1. Furthermore, microstructural features, such as decrease in the average grain size after deformation at 850 °C and 980 °C, the presence of many dislocation-free grains adjacent to grains with a high dislocation density, indicate that dynamic recrystall.zation has occurred as an efficient accommodation mechanism. SEM examination of the fracture sample after superplastic deformation reveals many voids on the fracture surface. By correlating with the result of tEM observation, it is suggested that the superplastic deformation in this alloy should be controlled by a grain boundary sliding-based mechanism accommodated by the movement of dislocation and dynamic recrystall.zation.

关键词： Activation energy Aluminum alloys Intermetallics Iron alloys Microstructure Recrystall.zation (metallurgy) Superplasticity tensile testing

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

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 rational.zes 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

Effect of surface layer softening from previous electrochemical corrosion on electrochemical cold drawing of Q235 steel bar

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journal of Iron and Steel Research International 2022年第5期29卷 819-835页

作者： j.l.guo t.j.Chen State Key laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou730050GansuChina

the effects of H_(2)SO_(4)concentration and current in electrochemical corrosion on surface layer softening or plasticizing of Q235 steel bar and their effects on subsequent electrochemical cold drawing(ECD)were *** results indicate that the electrochemical corrosion can soften or plasticize the surface layer of Q235 steel bar and then make the subsequent ECD be conducted more *** softening degree and thickness of the surface layer are continuously enhanced with increasing corrosion rate,i.e.,increasing H_(2)SO_(4)concentration or current,due to the generation of more vacancy clusters in deeper regions of surface *** vacancy clusters then relax dislocations through being absorbed during ECD,and the formation and movement of additional dislocation flux are thereby enhanced,resulting in the further obvious decrease in the drawing *** is also due to the enhanced formation and movement of additional dislocation flux that the dislocation density and thus the hardness of the surface layer are decreased,as well as that the texture structure is *** behaviors are enhanced as the corrosion rate increases.

关键词： Electrochemical corrosion Electrochemical cold drawing Surface layer softening Vacancy Additional dislocation flux

tHE INtERFACIAl BEHAVIORS OF AlUMINUM MAtRIX COMPOSItE IN DIFFERENt WElDING MEtHODS

维普期刊数据库评论

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维普期刊数据库

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Acta Metallurgica Sinica(English letters) 2004年第1期17卷 55-60页

作者： W.guo j.t.Niu j.F.zhai G.t.zhou M.z.Wang State Key laboratory of Advanced Welding Production technology Harbin Institute of Technology(HIT)Harbin150001China State Key laboratory of Metal Matrix Composite Shanghai Jiaotong University.Shanghai 200030.China

Non-interlayer liquid phase diffusion welding (China Patent) and laser welding methods for aluminum matrix composite are mainly described in this paper. In the non-interlayer liquid phase diffusion welding, the key processing parameters affecting the strength of joint is welding temperature. When temperature rises beyond solidus temperature, the bonded line vanishes. the strength of joint reaches the maximum and becomes constant when welding temperature is close to liquid phase temperature. Oxide film in the interface is no longer detected by SEM in the welded joint. With this kind of technique, particle reinforced aluminum matrix composite Al2 O3p/6061Al is welded successfully, and the joint strength is about 80% of the strength of composite (as-casted). In the laser welding, results indicate that because of the huge specific surface area of the reinforcement, the interfacial reaction between the matrix and the reinforcement is restrained intensively at certain laser power and pulsed laser beam. the laser pulse frequency directly affects the reinforcement segregation and the reinforcement distribution in the weld, so that the weldability of the composite could be improved by increasing the laser pulse frequency. the maximum strength of the weld can reach 70% of the strength of the parent.

关键词： non-interlayer liquid phase diffusion welding Al2O3p/6061 Alaluminum matrix composite laser welding interface behavior reinforcement

An improved diagnostic stratocumulus scheme based on estimated inversion strength and its performance in GAMIl2

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Science China Earth Sciences 2014年第11期57卷 2637-2649页

作者： guo zhun zhou tianjun Climate Change Research Center (CCRC) State Key laboratory of Numerical Modeling for Atmospheric Sciences & Geophysical Fluid Dynamics (lASG)

Based on satellite data and the estimated inversion strength(EIS) derived by Wood et al.(2006), a feasible and uncomplicated stratocumulus scheme is proposed, referred to as EIS scheme. It improves simulation of cloud radiative forcing(CRF) in the Grid-point Atmospheric Model of IAP/lASG version 2(GAMIl2.0) model. When compared with the original lower troposphere stability(ltS) scheme, the EIS scheme reproduces more reasonable climatology distributions of clouds and CRF. the parameterization partly corrects CRF underestimation at mid and high latitudes and overestimation in the convective region. Such improvements are achieved by neglecting the effect of free-tropospheric stratification changes that follow a cooler moist adiabat at middle and high latitude, thereby improving simulated cloudiness. the EIS scheme also improves simulation of the CRF interannual variability. the positive net CRF and negative stratiform anomaly in the East Asian and western North Pacific monsoon regions(EAWNPMR) are well simulated. the EIS scheme is more sensitive to sea surface temperature anomalies(SStA) than the ltS. therefore, under the effect of a warmer SStA in the EAWNPMR, the EIS generates a stronger negative stratiform response, which reduces radiative heating in the low and mid troposphere, in turn producing strong subsidence and negative anomalies of both moisture and cloudiness. Consequent decreases in cloud reflection and shading effects ultimately improve simulation of incoming surface shortwave radiative fluxes and CRF. Because of the stronger subsidence, a stronger anomalous anticyclone over the Philippines Sea is simulated by the EIS run, which leads to a better positive precipitation anomaly in eastern China during ENSO winter.

关键词： stratocumulus scheme AGCM cloud radiative forcing

Effect of long-term thermal Exposure on Microstructure and Stress Rupture Properties of GH3535 Superalloy

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journal of Materials Science & technology 2015年第3期31卷 269-279页

作者： t.liu j.S.Dong l.Wang z.j.li X.t.zhou l.H.lou j.zhang School of Materials Science and Engineering Dalian University of Technology Institute of Metal Research Chinese Academy of Sciences Shanghai Institute of Applied Physics Chinese Academy of Sciences Shenyang National laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

the evolution of microstructure and the stress rupture properties of long term thermally exposed GH3535 alloy have been investigated. It was found that M6 C carbides presented in the solid solution heat treated samples. During long term thermal exposure at 700 C, fine M12 C carbides precipitated preferentially at grain boundaries. these carbides coexisted with the pre-exiting M6 C. the stress rupture life of700 C/1000 h exposed sample under creep testing at 650 C/324 MPa is 93 h. It is much longer than that of the solid solution samples. No noticeable changes could be detected in both the microstructure and stress rupture lives when the samples were exposed for time longer than 1000 h M12 C carbides were found to be beneficial to the creep properties. the cracks initiated at the interface of M6 C carbides and matrix, which led to a lower creep rupture life.

关键词： GH3535 superalloy long term thermal exposure Micro

MICROStRUCtURE OF BINARY Mg-Al EUtECtIC AllOY WIRES PRODUCED BY tHE OHNO CONtINUOUS CAStING PROCESS

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Acta Metallurgica Sinica(English letters) 2008年第4期21卷 275-281页

作者： z.M. zhang t. lü C.j. Xu X.F. guo School of Materials Science ＆ Engineering Xi＇an University of Technology Xi＇an 710048 China

Directionally solidified binary Mg-Al eutectic alloy wires of approximately 5 mm in diameter were produced by the Ohno continuous casting （OCC） process and the microstructure was examined. It was found that the wires possess obvious unidirectional growth characteristic along its axial direction. the microstructure consists of parallel columnar grains that resulted from the competitive growth of equiaxed grains solidified on the head of dummy bar. Each columnar grain comprises regular eutectic a-Mg and β-Mg17 Al12 phases, which grew along the axial direction of the wires. the morphology of the eutectic is mainly lamellar, meanwhile rod eutectic exists. the formation of rod eutectic was attributed to the ＂bridging effect＂ caused by incidental elements in the alloy.

关键词： Mg-Al alloy Eutectic structure Directional solidification OCC process

Fluid-structure interaction in z-shaped pipe with different supports

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Acta Mechanica Sinica 2020年第2期36卷 513-523页

作者： Q.guo j.X.zhou X.l.Guan College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China Highway Science and technology Research Institute Xinjiang Production and Construction Corpsürümqi 830002China

Fluid-structure interaction(FSI)has a strong relation with layout of fluid delivery *** is liable to cause local ***,FSI analysis is necessary in many cases,especially for flexible pipe *** modeling consists of eight governing equations and then completely solved via the finite volume method(FVM).Friction,Poisson and joint couplings were discussed in detail to reveal the influence of a z-shaped pipe with different supports and elbows on *** the feasibility of solving FSI by FVM was verified,the different effects of free,fixed and elastic supports on FSI in the commonly used and simplified z-shaped pipe were further *** indicated that different support stiffness lead to various FSI *** coupling occurs at the elbow and less support is considered,then the pipe has a relatively large amplitude and complex pressure fluctuation.

关键词： Fluid-structure interaction Finite volume method z-shaped pipe Support stiffness