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journal of Rare Earths 2020年第7期38卷 770-775,I0004页

作者： m.S.Sadeq H.y.morshidy Basic Sciences Dept. Faculty of EngineeringSinai Univ.45511Al-ArishEgypt

The glass system under study was prepared and examined using the melt quenching procedures and XRD to emphasize the amorphous nature,*** of the prepared solid glass system was performed by a spectrophotometer in wavelengths from 190 to 1099 *** traditional techniques and standard formulas,the density,molar volume,refractive index,optical band gap and the optical filter characteristics were determined,then the influence of samarium oxide on some properties like the structure and optical,also the electrical properties were dissected.A novel formula was proposed to estimate the refractive index from the optical energy *** obtained samples are good optical filters especially the sample that contains 0.8 mol% of Sm2 *** this sample has the utmost density,the least molar volume,the maximum transmittance,least refractive index,the highest optical band gap and the least dc conductivity.

关键词： Alumino borate glasses Samarium oxide Optical properties Rare earths

Optimization of a High Speed Spinning Disk Spindle System for minimum RRO,NRRO,and Lightweight by Using G.A.

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厦门大学学报(自然科学版) 2002年第S1期41卷 89-90页

作者： y H Choi S T Kim K C yoon j m Kim y j Kang Dept.of mechanical Design and manufacturing Changwon National UniversityKyungnam 641-773Korea Dept.of mechanical Engineering Changwon National UniversityKyungnam 641-773Korea Senoir Research Engineer R&D Cente FAGHANWHA Bearing Corp.Kyungnam 641-020Korea Graduate Student Dept.of Mechanical Design and ManufacturingChangwon National UniversityKyungnam 6412773Korea

Law level of RRO(Repeatable Run Out),NRRO(Non Repe at able Run Out),and lightweight construction are a major trend in the high-speed HDD(Hard Disk Drive)sytem to reduce track misregestration and to achieve high track density,which lead to succeed in the ***,it is not easy to r educe RRO,NRRO,and the weight of the spinning disk spindle system efficiently because lightweight construction and or bearing stiffness changes often yields a decrease in the static and dynamic stiffness of the system,and consequently hi gh vibrations may be generated as a ***,it is of importance to e valuate in advance the accurate dynamic behavior of the high speed spinning disk spindle system of a HDD *** study introduces an optimum design of the high speed spinning disk spindle system of a HDD for minimum RRO,NRRO,and lightweight construction using a gene tic *** spinning disk,hub,and bearing components of a HDD system ar e modelled as appropriate finite elements respectively and their equations of mo tion are derived to construct the system equations of the whole spinning disk sp indle system of the HDD *** RRO and NRRO responses of the spinning disk,due to exciting forces arised from ball bearing faults and rotating unbalance,are *** the design optimation,the hub thickness,the disk thickness,bearing positio ns(or bearing span)and bearing stiffness were set as design *** uni que objective function is obtained by multiplying an appropriate weighting facto r by multi-objective functions,such as RRO,NRRO,and the total weight of HDD the *** constraints are maximum RRO limit,maximum weight linit,and the critical speed limit of the HDD spindle *** show that the RRO,NRRO,and weight are reduced by 6%,66.7%and 28%r espectively compared with the initial design of the HDD ***,thi s present study can be used for an optimum design of the spinning disk spindle s ystem of a HDD for lightweight construction

关键词： design optimization genetic algorithm multiobjective optimization repeatable run out non repeatable run out

EFFECT OF HEAT TREATmENT ON RECOVERy STRESS OF Fe-18mn-5Si-8Cr-4Ni ALLOy

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Acta metallurgica Sinica(English Letters) 1999年第5期12卷 743-746页

作者： Li, N. Wen, y.H. Xu, y.G. Tu, m.j. Li, P.Q. Liu, y.L. ma, y.L. Sichuan Univ Chengdu China

The effect of quenching temperature on the recovery stress of Fe 18mn 5Si 8Cr 4Ni shape memory alloy has been studied. The results show that both the maximum recovery stress σ h in heating and the recovery stress σ c at room temperature after heating increased as increasing quenching temperature increased, both σ h and σ c reached maximum at 650℃, and then decreased rapidly with the further increase in quenching temperature,but the descent degree of σ c was far bigger than that of σ h; When the quenching temperature is higher than 850℃, the further increase in quenching temperature had little effect on them; At random quenching temperature, σ c was far bigger than σ h.

关键词： shape memory alloy quenching recovery stress

Parameter Optimisation of Stress-strain Constitutive Equations Using Genetic Algorithms

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journal of materials Science & Technology 2003年第Z1期19卷 5-8页

作者： y. y. yang m. mahfouf D.A.Linkens Department of Automatic Control and Systems Engineering University of Sheffield Mappin St. Sheffield S1 3JD UK Department of Automatic Control and Systems Engineering University of Sheffield Mappin St. Sheffield S1 3JD UK Department of Automatic Control and Systems Engineering University of Sheffield Mappin St. Sheffield S1 3JD UK

The accuracy of numerical simulations and many other material design calculations, such as the rolling force, rollingtorque, etc., depends on the description of stress-strain relationship of the deformed materials. One common methodof describing the stress-strain relationship is using constitutive equations, with the unknown parameters fitted byexperimental data obtained via plane strain compression (PSC). Due to the highly nonlinear behaviour of the constitutive equations and the noise included in the PSC data, determination of the model parameters is difficult. Inthis paper, genetic algorithms were exploited to optimise parameters for the constitutive equations based on thePSC data. The original PSC data were processed to generate the stress-strain data, and data pre-processing wascarried out to remove the noise contained in the original PSC data. Several genetic optimisation schemes have beeninvestigated, with different coding schemes and different genetic operators for selection, crossover and *** was found that the real value coded genetic algorithms converged much faster and were more efficient for theparameter optimisation problem.

关键词： Genetic algorithms, Parameter optimisa tion, Aluminium alloy, Flow stress, Constitutive equations

microstructure and mechanical properties of TiAl/TiAl joints brazed with a newly developed Ti–Ni–Nb–Zr quaternary filler alloy

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Progress in Natural Science:materials International 2022年第6期32卷 758-768页

作者： H.S.Ren y.L.Shang X.y.Ren y.j.jing H.P.Xiong y.y.Cheng Welding and Plastic Forming Division Beijing Institute of Aeronautical Materials

A novel Ti-Ni-Nb-Zr quaternary filler alloy with the composition of Ti-(19～25)Ni-(15～25)(Nb+Zr)(wt.%) was *** filler alloy was composed of(Ti,Nb)ss,(Ti,Zr,Nb)ss+(Ti,Zr)2Ni,α-Ti and Ti2Ni *** was fabricated into filler foil with a thickness of about 45 μm by a rapid solidification *** results indicate that the liquidus temperature of the Ti-Ni-Nb-Zr brazing alloy was about 978℃,and the brazing alloy presented excellent wettability on TiAl *** TiAl joint mainly consisted of β/B2 phase,Ti2Al,Ti2AlNi and α2-Ti3Al *** diffusion of Al atom from base metal to brazed seam led to the formation of Ti2Al and *** that no previously references on XRD pattern of Ti2AlNi compound can be found,Ti2AlNi cast alloy specimen was specially prepared and XRD peaks were specially *** micro-hardness and bending strength tests of the Ti2AlNi phase were carried out,and the results were 761 HV and 192 mPa,*** brazing parameters of 1010 ℃/10 min offered the joint shear strength of 280 mPa at room temperature,and the joints exhibited tensile strength of 372 mPa at room temperature and 340 mPa at 750 ℃,indicating that the newly developed filler alloy could offer a stable high-temperature strength.

关键词： TiAl Brazing Filler alloy microstructure mechanical properties

Effect of Si Content on mechanical Properties of a mo and V Free Low Alloy Cast Steel for Automobile Cold Pressing Die

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journal of materials Science & Technology 2008年第3期24卷 313-316页

作者： B.H.Kim j.S.Shin S.m.Lee B.m.moon H.D.Kim S.y.ju O.y.Choi Advanced materials R＆D Division Korea Institute of Industrial Technology Incheon 406-840 Korea Tooling Center GM Daewoo Auto ＆ Technology Co. Incheon 403-714 Korea

The effects of Si content on combinations of important properties such as hardness, hardenability, and weldability in addition to strength increment were systematically investigated to develop a mo and V free low alloy cast steel for automobile cold pressing die insert. For the evaluation of the applicability as the die insert, the mechanical properties were measured after spheroidization annealing （SA）, quenching and tempering （Q/T）, and flame hardening （FH） treatments, respectively. The developed 0.8%-1.6%Si containing mo and V free alloy cast steels showed excellent matrix strengthening effect, hardenability, and weldability, fulfilling the industrial criterion of the mechanical properties for the die insert.

关键词： Low alloy cast steel Cold pressing die Die insert matrix hardening Flame hardening

HIGHLy DISPERSED mULTI-WALLED CARBON NANOTUBES IN WATER/ETHANOL AND ITS APPLICATION FOR PVA COmPOSITE

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Acta metallurgica Sinica(English Letters) 2005年第3期18卷 389-396页

作者： X.y.Tao j.m.Xu F.Liu G.L.Xu InstituteofmaterialsPhysicsandmicrostructures DepartmentofMaterialsScienceandEngmeeringZhejiangUniversityHangzhou310027China CollegeofElectronicInformation HangzhouDianziUniversityHangzhou310018China

Two carboxylation processes were carried out to modify multi-walled carbon nanot ube bundles (m-mWNTs). The results showed that both of the m-mWNTs could be high ly dispersed in water with the concentration up to 25 and 15mg/mL in ethanol wit hout obvious deposition or conglomeration over 6 months. FTIR, Raman, TGA and TE m characterizations of the m- mWNTs showed that hydroxyl and carboxyl groups hav e been attached with mWNTs, and that the nanotube structure was only damaged a l ittle after modification treatments in mixed acids over 24h. Above prepared nano tube suspensions in water were successfully used as a filler of thermoplastic PV A composite to enhance its electrical conductivity. The results showed that the addition of m-mWNTs greatly improved the conductivity and the threshold of mass fraction was about 5wt%. The results also proved that purification process was n ot needed because of high purity of the raw mWNTs prepared in our group.

关键词： carbon nanotube polyvinylalcohol composite conductivity

Enhancing the high-temperature creep properties of mo alloys via nanosized La_(2)O_(3) particle addition

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journal of materials Science & Technology 2022年第35期130卷 53-63页

作者： P.m.Cheng C.yang P.Zhang j.y.Zhang H.Wang j.Kuang G.Liu j.Sun State Key Laboratory for mechanical Behavior of materials Xi’an Jiaotong UniversityXi’an 710049China School of mechanical Engineering Chengdu UniversityChengdu 610106China

molybdenum(mo) alloys with different La_(2)O_(3)particle additions(0.6,0.9,1.5 wt.%) were prepared by powder metallurgy to investigate the effect of La_(2)O_(3)particles on microstructural evolution and creep behavior of the *** mo,annealed at 1500℃ for 1 h,presented a fully recrystallized microstructure characterized by equiaxed *** alloys doped with La_(2)O_(3)particles(mo-La_(2)O_(3)alloys),on the other hand,exhibited fibrous grains elongated in the rolling direction of the *** contrast to the shape of the grains,the average grain size of the alloys was found to be insensitive to the addition of La_(2)O_(3)*** La_(2)O_(3)particles with diameters ranging from 65 to 75 nm were distributed within the grain *** creep tests showed that dislocation creep was the predominant deformation mode at intermediate creep rate(10^(-7)s^(-1)-10^(-4)s^(-1)) in the present *** creep stress exponent and activation energy were found to decrease with increasing temperature,particularly within the low creep rate regime(mo-La_(2)O_(3)alloys exhibited remarkably greater apparent stress exponent and activation energy than pure mo.A creep constitutive model based on the interaction between particles and dislocations was utilized to rationalize the nanoparticle-improved creep *** was demonstrated that low relaxed efficiency of dislocation line energy,which is responsible for an enhanced climb resistance of dislocations,is the major creep strengthening mechanism in the mo-La_(2)O_(3)*** addition,the area reduction and creep fracture mode of the mo-La_(2)O_(3)alloys were found to be a function of the creep rate and temperature,which can be explained by the effect of the two parameters on the creep and fracture mechanisms.

关键词： mo alloys Nanosized particles Creep strength Deformation and fracture

Hybrid finite-discrete element modelling of asperity degradation and gouge grinding during direct shearing of rough rock joints

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International journal of Coal Science & Technology 2016年第3期3卷 295-310页

作者： H. y. Liu Haoyu Han H. m. An j. j. Shi School of Engineering and ICT University of TasmaniaHobart TAS 7001 Australia School of Civil & Environmental Engineering University ofScience and Technology Beijing Beijing China

A hybrid finite-discrete element method was implemented to study the fracture process of rough rock joints under direct shearing. The hybrid method reproduced the joint shear resistance evolution process from asperity sliding to degradation and from gouge formation to grinding. It is found that, in the direct shear test of rough rock joints under constant normal displacement loading conditions, higher shearing rate promotes the asperity degradation but constraints the volume dilation, which then results in higher peak shear resistance, more gouge formation and grinding, and smoother new joint surfaces. moreover, it is found that the joint roughness affects the joint shear resistance evolution through influencing the joint fracture micro mechanism. The asperity degradation and gouge grinding are the main failure micro-mechanism in shearing rougher rock joints with deeper asperities while the asperity sliding is the main failure micro-mechanism in shearing smoother rock joints with shallower asperities. It is concluded that the hybrid finite-discrete element method is a valuable numerical tool better than traditional finite element method and discrete element method for modelling the joint sliding, asperity degradation, gouge formation, and gouge grinding occurred in the direct shear tests of rough rock joints.

关键词： Hybrid FEm-DEm Rock joint Asperity sliding Asperity shearing Fragment grinding

NUmERICAL SOLUTION OF UNSTEADy DENSE PHASE TRANSPORT OF PULVERIZED COAL

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journal of Hydrodynamics 1991年第3期3卷 116-124页

作者： A.L.Ren y.L.ma B.H.Zhong j.m.Shi Department of mechanics Zhejiang University Hangzhou 310027 P.R.China Shanghai Power Equipment Research Institute Shanghai 200240 P.R.China

It presents the one-dimensional unsteady dense transport equation in the tube for mHD pulverized coal feed. The simplified frictional force term introduced by Liu is used in the equation. The numerical solution has been got by using macCormack method. The results show that there exists optimal loading rate in which state velocity is not oscillation along a tube. It is well agreed with measurement, it also prevents a sediment in the tube.

关键词： Coal Handling Coal Pulverizers Computers Applications Fluid mechanics mathematical models