最新刊期
卷 ， 期 10 ， 2006
- 摘要：Presence of liquid-liquid structure transition has been observed in Bi-20.5Te at 642 ℃ by measuring its electric resistivity with temperature increase. Through analyzing the atomic bonding mechanism of Bi-Te alloy melt with different compositions at different temperatures, it was concluded that the structure transition is arising from change in atomic cluster in the melt. The solidification curves of the alloy before （600 ℃） and after （700 ℃） structure transition has been mapped and its microstructure has been observed. The results show that compared with melt before structure transition at holding treatment, the alloy after structure transition holding at 700 ℃ needs higher undercooling degree and releases sharper latent heat during solidification, and possesses finer solidification microstructure, which is attributed to the debonding of Bi-Bi cluster and Bi-Te cluster in the melt structure, leading to uniform distribution of the melt to influence the atom diffusion during solidification, further to influence the solidification behavior and structure.关键词：Bi-20.5Te Alloy;Melt Structure Transition;Solidification Behavior and Structure
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- 203
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发布时间：2023-12-18 - 摘要：SiO2 sol sealing agent was prepared from tetraethoxysilane（TEOS）by ethyl alcohol as solvent and hydrochloric acid as catalyst.The Fourier transformed infrared spectrometry（FTIR）contains dilation flutter absorption peak of S-O-Si,which shows the presence of SiO2 particle in solution.The sealing agent has a great stability at elevated uemperature because the strength of dilation flutter absorption peak of Si-O-Si does not change with heat treatment temperature.It could be observed that the SiO2 sol sealing agent fills up the hole of micro-arc oxidation coating on magnesium alloy.The corrosion rate of MAO coating sealed by SiO2 sol can be reduced from 106mg/（m2·h）to 32 mg/（m2·h）.Moreover the anti-oxidizing performance of MAO coating at 410 ℃ is greatly improved by sealing,and the coating sealed by SiO2 sol offers the effective protection for magnesium alloy substrate.
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发布时间：2023-12-18 - 摘要：Distribution of magnetic strength is measured by the small induction coil method.The results show that the magnetic strength is higher inside the coil,and then is attenuated toward both ends.Axial magnetic intensity increases with the increases of the power,and decreases with the decrease of the radial,slightly decreasing from the slit to the middle of the segment.Radial magnetic intensity is sharply decreased with increasing in radius and coils.Axial magnetic intensity is higher than radial magnetic intensity,and is more important for electromagnetic confinement.关键词：Electromagnetic Confinement;Cold Crucible;Magnetic Intensity
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- 323
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发布时间：2023-12-18 - 摘要：Effects of 1%～3% Di（Nd∶Pr=3∶1）addition on the microstructure and mechanical properties of Mg-10Al Mg alloys have been investigated.The results show that microstructure of the Mg-10Al alloy can be obviously refined due to the precipitation of bulky Al2（Nd,Pr）phase and rod Al 11（Nd,Pr）phase in the alloy with Di addition.Di can greatly improve the mechanical properties of as-cast Mg-10Al alloy.The maximum tensile strength and elongation of alloy can be observed with 2% Di addition due to bulky Al2（Nd,Pr）phase dominant in the matrix,while the tensile strength,especially elongation,is slightly decreased with 1% Di addition due to Al 11（Nd,Pr）phase increase.关键词：Mg-Al Alloy;Di;Grain Refinement;Mechanical Properties
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- 112
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发布时间：2023-12-18 - 摘要：The composition and morphology of Cu-coated SiCp powder prepared by electro-plating have been investigated.Moreover,Cu-35%SiCp heat sink materials were fabricated by hot pressing based on the coated powder,and its microstructure and thermo-physical properties have been observed.The results show that SiCp particle is uniformly distributed in the matrix with ideal interfacial bonding.With a given condition,the thermal conductivity of the Cu-35%SiCp heat sink materials is 165.7 W/（m·K）and the thermal expansion coefficient is 15.1×10-6/K in the range of 30～200 ℃,which provides a reference for further research.关键词：Heat Sink Material;Electro-plating;Thermal Conductivity;Thermal Expansion Coefficient
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- 162
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发布时间：2023-12-18 - 摘要：Principle and structure of low rotating duct apparatus for preparing semi-solid slurry have been expounded.Fuzzy control is employed to improve the precision of temperature-control system of the apparatus,in which the structure design and hardware-software schematic of the system are described in detail.The practical application verifies that fuzzy control can improve the temperature-control efficiency of the apparatus,realizing the ideal control for microstructure of semi-solid Al alloy.关键词：Fuzzy Control;Low Rotating Duct;Semi-solid;Microstructure
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发布时间：2023-12-18 - 摘要：The effects of size and concentration of droplet on the microstructure of rapidly solidified Cu-Co alloy in drop-tube have been investigated.The experimental results demonstrate that Co-rich particle in the droplet becomes more dispersive with the decrease of the droplet size.With Co concentration approaching towards the critical composition of metastable miscibility region,the liquid-liquid phase transformation is easier to be created in the molten alloy,and the average radius of Co-rich particle becomes bigger and bigger in the solidified microstructure.Co-rich particle is nucleated in the droplet and taken Marangoni movement towards high temperature region in center of droplet with temperature gradient during liquid-liquid phase transformation,resulting in the formation of Co-poor on the surface of the powder.关键词：Cu-Co Alloy;Rapid Solidification;Drop-Tube;Liquid-liquid Transformation;Metastable Miscibility Region
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- 251
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发布时间：2023-12-18 - 摘要：Research methodology and development of quantitative analysis on particle distribution in particle reinforced metal matrix composites have been presented on the basis of macro and micro simulation of solidification process of SiC particle reinforced Al-7Si composites made by stirring casting,and the quadrat method and variance analysis method are considered in the numerical simulation.Effects of particle volume fraction on particle distribution homogeneity have been investigated,and the simulated results were compared with experimental ones.The results show that the effects of different technical parameters on microstructure and particle distribution can be analyzed accurately when macro and micro numerical simulation are coupled with quantitative analysis techniques.关键词：Metal Matrix Composites;Particle Distribution;Microstructure;Numerical Simulation;Quantitative Analysis
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- 418
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发布时间：2023-12-18 - 摘要：The operation principle of magnesium melting furnace was introduced in detail.Both hardware and software realization of its all-in-one control system based on Advantech company’s MIC-2000 series industrial PC,in which control and management functions are integrated,has been developed.关键词：Magnesium Alloy Melting Furnace;Industrial PC;Control System
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- 77
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发布时间：2023-12-18 - 摘要：Numerical simulation of flow and solidification process of liquid steel in crystallizer in un-steady filling process has been conducted based on flow field coupled with temperature field using CFD commercial software Flow-3D in 0.2% carbon steel billet with 165 mm×165 mm continuous casting.The simulated results indicate that inside-cooling apparatus in mould can effectively promote heat transfer efficiency and decrease impaction depth of liquid steel.Inside-cooling apparatus can improve the billet quality due to relief the flow velocity and more homogeneous flow of liquid steel.关键词：Billet Continuous Casting;Inside-cooling Apparatus;Numerical Simulation
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- 210
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发布时间：2023-12-18 - 摘要：Lost foam casting control-transferring semi-solid process for cast iron was described.First,the foamed pattern was produced with polystyrene and polymethyl methacrylate bead;second,the liquid metal is not prepared semi-solid slurry before pouring but directly poured at slightly below liquidus temperature to control the creation of small amounts of solid phase during pouring.Based on the mentioned technique,the size and surface of produced cast iron castings can be greatly improved,meanwhile,the techniques have the advantages of riser-free and no sand treatment.关键词：Cast Iron;Lost Foam Casting;Semi-solid Casting;Control-transferring
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- 205
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发布时间：2023-12-18 - 摘要：A linear-billet horizontal continuous casting set-up with ultrasonic power system has been designed to improve the utility of the horizontal continuous casting linear-billet,and analogue experiment has been conducted on the set-up using Al-Si alloy for bonding-line.Microstructure and surface quality of the linear-billet were observed by OM,and the mechanical properties have been examined.The results show that the microstructure of billet is refined,and the surface quality as well as mechanical properties is improved under the condition of ultrasonic power.关键词：Ultrasonic Power;Horizontal Continuous Casting;Al-Si Alloy
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- 151
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发布时间：2023-12-18 - 摘要：Based on practical production,effects of filling time on quality of die castings have been expounded.Power comparison and p-Q2 map were employed to check the injection power of die casting machine.The results show that the die casting machine can meet the technological requirements of production of die casting parts with p-supply less than p-demand.关键词：Injection Power of Die Casting Machine;Filling Time;p-Q2 Map
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发布时间：2023-12-18 - 摘要：Effects of different Nd contents on high cycle fatigue of die cast magnesium alloy AZ91D have been examined at the condition of stress ratio of 0.1.The results indicate that with increasing in Nd contents,the grain size in microstructure of the alloy is refined gradually,and the size and amounts of β-Mg 17Al 12 phase are decreased and dispersively distributed.With Nd contents increase,the tensile strength,elongation and condition fatigue strength of die cast AZ91D+xNd alloy can be improved,where the maximum tensile strength of 207 MPa,elongation of 6.8% and condition fatigue strength of 70 MPa can be observed with 1.0% Nd addition.SEM analysis shows that the alloy containing 1%Nd exhibits the maximum fatigue propagation regions.There exists rip edge and dimple in rupture of three different Nd content alloys,showing quasi-cleavage and toughness fracture.关键词：Die Casting;Magnesium Alloy;Nd;High Cycle Fatigue
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- 201
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发布时间：2023-12-18 - 摘要：Effects of solution treatment（T4）and solution plus artificial aging treatment（T6）on microstructure and mechanical properties of Al-5Cu alloy have been investigated in direct squeezing casting.It was found that squeezing casting can promote the diffusion rate of atoms during heat treatment and decrease heat treatment time.The mechanical properties of alloys can be improved due to the heat treatment changing the structure.Compared with those of cast alloy,the mechanical properties of alloy treated at 525～530 ℃ for 4 hours can be obviously improved,where the optimized tensile strength of 389.6MPa and elongation of 10.8% can be observed at holding time for 15 hours.Solid solution Al-5Cu alloy in direct squeezing casting exhibits apparently natural ageing characteristics.It is easy to precipitate stable strengthening GP zone and θ’’ phase for Cu atom in the Al-5Cu alloy under the condition of natural environment,which results in the higher mechanical properties of alloys under solid solution plus natural aging condition than those under T6 condition due to the uniformly distributed strengthening phase.关键词：Heat Treatment;Squeezing Casting;Al-Cu Alloy;Mechanical Properties;Microstructure
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- 219
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发布时间：2023-12-18 - 摘要：Effects of die design and processing parameters on control arm of automobile in squeezing casting have been investigated.The optimization of processing parameters,such as the sectioned width of ingate,composition and pressure,has been paid attention to.The experimental results indicate that the control arm with sound microstructure and fine grain size whose mechanical properties approach to those of forging parts can be produced with sectioned width of 10mm and specific pressure of 50 MPa and Fe content less than 0.1%.关键词：Control Arm of Automobile;Squeezing Casting;Mechanical Properties
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- 227
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发布时间：2023-12-18 - 摘要：Influence of temperature on thermal expansion ability of photocurable resin specimens used in rapid prototyping（RP）has been approached.The experimental results indicate that with different temperatures,while the thermal expansion trend is the same,the thermal expansion rate is different.With increasing in the temperature,the thermal expansion curves and thermal expansion rate as well as the maximum expansion rate of the resin prototyping are increased.Based on above results,the baking processing for mold shell for the rapid-precision casting is as follows:photocurable resin prototypes come into furnace for baking at 80～100 ℃,then the temperature of the furnace is increased to 950 ℃ by 150 ℃/h for 30 min and then cool off.关键词：Photocurable Resin;Rapid Precision Casting;Shell Mold;Thermal Expansion
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- 291
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发布时间：2023-12-18 - 摘要：Hollow spiral stainless steel cooling-water-sprayer was produced by investment casting.Heat mould gravity casting was employed to produce the castings at a high temperature,in which pouring is conducted by first slow then rapid and first small then big flow volume.The defects of sand-slag and gas-hole are absent in the water-cooling-sprayer whose surface is clean and qualified rate is more than 90%.The diameters of pulverization area are more than 1.5m and rate of pulverization is more than 90%,exhibiting excellent pulverized effects.The absence of corrosion of the sprayer can be observed after 2000h salt spray testing,showing excellent wear resistant and corrosion resistant.关键词：Hollow Spiral;Investment Casting;Water-cooling-sprayer;Heat Mould Gravity Casting
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- 97
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发布时间：2023-12-18 -
- 摘要：A set of sand treatment and reclamation set-up for lost foam casting suitable for small-middle enterprises was developed based on referring previous practical experience,which is characterized by reliable temperature-reduction,completely micro-powder-removal,high sand-production rate and low energy-consumption as well as simple structure.Dry-sand cooling and micro-powder removal can be fully controlled under closed state condition.关键词：Lost Foam Casting;Sand-treatment Equipment;Environmental-protection
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- 102
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发布时间：2023-12-18 - 摘要：Influence of annealing on tensile strength and microstructure of AZ91 magnesium alloy was investigated.Experimental results show that the occurrence of static recrystallization in magnesium alloy sheet during annealing can be observed,which begins at annealing of 200 ℃,while its recrystallization temperature of the alloys is in range of 200 ℃ to 250 ℃.The influencing mechanism of annealing temperature and annealing time on the microstructure,grain size,hardness and mechanical properties of the alloy sheet was approached.关键词：AZ31 Magnesium Alloy;Annealing Treatment;Static Recrystallization;Microstructure;Mechanical Properties
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- 995
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发布时间：2023-12-18 - 摘要：Effects of yttrium on microstructure and mechanical properties of Mg-3Zn-xY（x=0.5,1.5,3,6）alloys were investigated by X-ray and microscope.The results show that the size and amounts of particles in the matrix and at grain boundary are increased with increasing yttrium content.The type of second phase in the alloy is found to be dependent upon the Zn/Y ratio.With the Y content increases,the second phase is converted from Mg7Zn3 +I phase to I phase +W phase,and to W phase +H phase to H phase.The shapes of the second phases at the grain boundaries are transformed from punctate to short rodlike,and to reticular particles.The tensile strength,hardness and impacting toughness of alloy are improved while the plasticity is decreased with Y content increasing.However,the comprehensive mechanical properties are descended with 6% Y addition.关键词：Mg-Zn-Y Alloy;Y;Mg Alloy;Microstructure;Mechanical Properties
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- 460
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- 7
发布时间：2023-12-18 - 摘要：Effects of Re modification and Sr modification on constituent and morphology of surface oxidized film of A356 aluminum alloy have been observed by X-ray and SEM.The influential mechanism of Re modification and Sr modification on hydrogen content in A356 melt has been understood from view of compactness and completeness of surface oxidized film.The results indicate that compound LaAl 11O 18 was formed on surface oxidized film on Re modified A356 alloy,which makes surface oxidized film more compact and very flat with almost no-crack defects to effectively prevent reaction of Al from water.While a large number of compound SrAl2O4 was formed on the surface oxidized film of Sr modified alloy,which deteriorates the compaction of surface oxidized film to generate amounts of track from crack in the surface oxidized film to greatly promote the reaction between Al and water due to the fresh liquid Al continuously exploding over air,resulting in the sharp increase of hydrogen content in the melt.关键词：A356 Aluminum Alloy;RE;Surface Oxidized Film
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- 137
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发布时间：2023-12-18 - 摘要：Effects of ageing on microstructure and hardness of cast Cu-15Ni-8Sn-xTi alloy were investigated.It was found that the cast Cu-15Ni-8Sn-xTi alloys are strengthened due to the formation and growth of the modulated structure and the metastable γ’ phase similar to that of the cast Cu-15Ni-8Sn alloys.0.073% Ti can completely dissolve into Cu-15Ni-8Sn and accelerate the formation and growth of γ’ phase in matrix and cell structure in grain boundary.The newly-formed phase of Ni3Ti can restrain the formation and growth of γ’ phase and completely constrain the formation of cell structure.关键词：Cast Cu-15Ni-8Sn-xTi Alloy;Microstructure;Hardness;Ageing
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- 182
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发布时间：2023-12-18 - 摘要：Al3Zr and Al2O3 particles reinforced aluminum matrix composites have been in-situ synthesized through the direct melt reaction using Al-ZrOCl2 components.The formation of composites has been conducted by the conventional casting method and squeezing casting at 720 ℃.SEM observation shows that the absence of shrinkage porosity and shrinkage hole in the microstructure of squeezed samples with fine grain can be found.Squeezing casting is an interaction process of crystallized solidification and plastic deformation at a high pressure,where expansion energy from applied pressure can increase the nucleation rate,which is beneficial to improving the comprehensive mechanical properties and wear resistance of the composites.关键词：Squeezing Casting;Particle Reinforcement;Al Matrix Composites;Solidification Microstructure
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- 334
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发布时间：2023-12-18 - 摘要：Al2O3-TiC/Al composites were prepared by adding CO2 into Al-Si alloy melt containing Ti.Microstructure of the composites has been observed by X-ray diffraction（XRD）,scanning electron microscope（SEM）and transmission electric microscope（TEM）.It is found that Al2O3 and TiC particle with grain size of 0.2～1.0 μm formed from in-situ reaction of CO2 with Al and Ti can be uniformly distributed into the matrix.In addition,formed Al2O3 and TiC numbers are obviously dependent on the injection time of CO2.关键词：In-Situ Reaction;Aluminum-based Composites;Microstructure
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- 200
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- 14
发布时间：2023-12-18 - 摘要：A new preparation method was developed to prepare Al2O3 particle reinforced Cu matrix composites,where Cu powder is added into Al（NO3）3 solution with dfferent Al（NO3）3 concentration and stirred to be paste to be dried at 80 ℃,and then the Al（NO3）3 is decomposed into Al2O3 particle at 500 ℃ in hydrogen atmosphere,then the powder is heated up to composites.The effects of Al2O3 content on the properties of the composites have been examined.The results show that with increasing in Al2O3 content,the decreased.Meanwhile,the maximum value of the hardness of composites can be obtained with 1% Al2O3 content.关键词：Dispersive Strengthening;Cu Matrix Composites;Electric Conductivity;Hardness;Densitv
- 2
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- 105
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- 0
发布时间：2023-12-18 - 摘要：Al2O3/Cu composites are attractive engineering materials for application requiring high strength,high thermal and electric conductivity and resistance to softening at an elevated temperature.Present status of preparation of Al2O3/Cu composites by internal oxidation and its acquiring conditions were reviewed,especially internal oxidized kinetics and thermo-kinetics.The excellent properties of the Al2O3/Cu composites at ambient and at elevated temperatures were verified by internal oxidation using Cu2O.The service life of composites electrode is 3～5 times higher than that of conventional Cu-Cr-Zr electrode based on installment experiment of spot-welding electrodes.Finally,the problems in preparation of Al2O3/Cu composites by internal oxidation were paid attention to.关键词：Internal Oxidation;Al2O3/Cu Composites;Al2O3
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- 240
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发布时间：2023-12-18 -
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