最新刊期
卷 ， 期 5 ， 2005
- 摘要：The effects of B content and holding time on solidification microstructure and cooling curves of Al-7Si alloy were investigated.The characteristic values of eutectic solidification section in cooling curves were measured by thermal analysis,and the average area and shape factors of eutectic phase were observed by the image analysis.It was found that B addition has a slight effect on the shape factors of the Si phase and characteristic values in cooling curve.The average area of the Si phase is decreased with the decrease of the primary grain size in a given grain size range.关键词：Hypereutectic Al-Si Alloy;Refinement;Modification
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发布时间：2023-12-18 -
- 摘要：The thin-walled effects of a new directionally solidified superalloy were investigated aiming at tubular hollow specimens with wall thickness of 1.0,1.2,1.4 mm similar to the hollow blades made by the net-shape investment casting.The results showed that the stress-rupture of the thin-walled specimens can not be obviously reduced by comparing with that of the standard ones with the diameters of 5mm,indicating the alloy has no obvious thin-walled effects for the experiment condition.The experimental results were analyzed from the view of processing factors and microstructure.关键词：Superalloy;Turbine Blade;Thin-walled Effect
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- 265
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发布时间：2023-12-18 - 摘要：The corrosion resistance of the Ni-P-nano TiO2 electrolyte compound plating immersed in the different solutions including HCl,H2SO4,HNO3,NaOH and NaCl was systematically exaimined by the full-soak corrosion testing.Results indicated that the Ni-P-nano TiO2 compound plating possesses the higher corrosion resistance to acid,alkali and salt comparing with the Ni-P electrolyte plating.The corrosion resistance of the compound plating in salt and alkali solutions is superior to that in acid solution.The corrosion morphology of the compound plating belongs to uniformly corrosion shape in NaOH,NaCl and HCl solutions while belongs to pitting corrosion in H2SO4,HNO3 solutions.It is significantly important for improving the corrosion resistance to keep the integrality of the Ni-P-nano TiO2 electrolyte compound plating in the erosion solution.关键词：Ni-P-nano TiO2;Electrolyte Compound Plating;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：The effects of some processing parameters on the density of pressure-reduction solidification sample were approached based on detecting the quality of liquid aluminum by SGJ-I type instrument.An optimized processing parameters can be obtained by examining corresponding relation of the density value of the pressure-reduction solidification sample with the grade of pin-hole degree of the sample in sand mold.And the results verified the reliability and stability of the instrument for detecting the refining effects in practice.关键词：Liquid Aluminum;Density;Detection
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发布时间：2023-12-18 - 摘要：A kind of wear resistant coatings consisting of Al2O3 and epoxy resin has been developed,which can be applied to renew the worn surface of anodic oxidation film pf duralumin alloy in military equipments.The effects of the surface treatment of Al2O3 powder by the heterogeneous isotropic distillation process on the wear resistance of the coating were analyzed.The IR spectra of the powder showed that the distillation effectively dehydrates hydrous Al2O3 powder,and succeeds in substituting the hydrate water with butane molecular.The SEM photos demonstrated that the Al2O3 powder is well dispersed in resin.The coating testing results showed that the wear resistance and adhesion can be obviously improved and the wear weight loss is decreased by 43% with the addition of treated Al2O3 powder.关键词：Anodic Oxidation Film;Wear-resistant Coating;Al2O3;Surface Modification;Wear Resistance
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发布时间：2023-12-18 - 摘要：Mischmetal absorptivity and its effects on the element contents in pure magnesium and AZ91D alloy were investigated.The results showed that the mischmetal absorptivity was decreased with the increase of mischmetal addition,and proper mischmetal addition can maintain mischmetal absorptivity over 75% in pure magnesium and 90% in AZ91d alloy.It was found that under different amounts of mischmetal addition,their contents did not exceed 1.6% for pure magnesium and 1.9% for AZ91D alloy in the experiments.The mischmetal addition reduced Cl contents below 0.001% in pure magnesium and AZ91D alloy.The mischmetal addition can lead to the reduction of Al content and has little effect on Zn,Mn,Fe,Cu,Ni and Si contents.关键词：Mg Alloy;Mischmetal;Absorptivity;Element Content.
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- 286
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发布时间：2023-12-18 - 摘要：Microstructure and properties of 2519 alloy during aging process at 180 ℃ were researched by means of optical microscopy （OM）,transmission electron microscopy（TEM）,scanning electron microscopy （SEM） and hardness test.The results showed that three aged stages are observed during the aging process of 2519 aluminum alloy at 180 ℃.The peak-aged time is 12 h.As the alloy for 5 h aging,a little amounts of discrete θ（or θ′） phase were precipitated from the grain boundaries,while no obvious precipitated phase in grain is found.Continuous chain-like θ（or θ′） phase precipitates were found on the grain boundaries and θ″ strength phase was commonly precipitated from the grain at peak-aged state.θ（or θ′） phase precipitates on the grain boundaries become coarse and spheroidization in a discrete state at aging for 20h,meanwhile the θ′ phase precipitated from the grain become coarse too.The elongation of the alloy was decreased with the increase of the aged time.关键词：2519 Aluminum Alloy;Aging;Microstructure;Mechanical Properties
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- 324
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发布时间：2023-12-18 -
- 摘要：As one of the basic testing methods,the DSC analytical method plays a unique role in measuring the basic thermal physical parameters of materials,such as changes in specific heat,enthalpy,in comparison with other methods.The measurement and application of baseline in the DSC measurement testing were introduced,which plays a key role in reducing error.The results showed that crucibles with different qualities can result in different baseline to further influence the analysis of experimental data.关键词：Thermal Analysis;DSC;Baseline;Baseline Measurement
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发布时间：2023-12-18 - 摘要：Precision castings with high precision and quality include turbine blade and impeller for aerospace and aviation, gasturbine impeller,booster impeller,Ti alloy castings as well as large complex thin-walled aluminum alloy castings,whose common features are high difficulties in processing and high quality and high value-addition.The production of precision castings with high precision and high quality were rapidly developed based on the introduction of advanced technology and equipment in last two decades.And the technology and product quality can be significantly improved.
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发布时间：2023-12-18 -
- 摘要：A method of extensive scouting of liquid isolated section combining with the calculation of solidification shrinkage in the equivalent liquid pools was put forward to simulate the shrinkage hole formation in TiAl alloy castings in investment casting,meanwhile,the size and formed location of the shrinkage hole were predicted.The simulated results are well in agreement with the practical results,indicating that the method can accurately predict the size and location of the shrinkage hole.关键词：TiAl Alloy;Investment Castings;Numerical Simulation;Shrinkage Hole;Isolated Section
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发布时间：2023-12-18 - 摘要：Macro and micro models are coupled with each other by latent heat treatment in simulation on microsegregation.The validity of simulation is directly determined by the model for latent heat treatment.A new advanced model for latent heat treatment was introduced into microsegregation models and simulation on microsegregation in the ingot of Al-4.5Cu alloy was carried out.The main kinetic factors influencing microsegregation were accounted for in the modeling including secondary arm coarsening,inverse-diffusion of solid solute,dendrite tip undercooling and variable diffusion coefficient with temperature.The deforming grid technology was applied for tracking the moving interface,and the iterative method was employed for resolving the diffusion equation and solute conservation equation.Simulation results are in good agreement with experimental results based on abbreviated coupling method.关键词：Latent Heat;Microsegregation;Numerical Simulation
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发布时间：2023-12-18 -
- 摘要：The tensile test at elevated temperatures show that either die cast AZ91 containing 1%Y or 1%MM Mg alloy has the higher strength than AZ91,in which the strength of AZ91 containing 1%Y is the higher than that of AZ91 containing 1%MM.The AZ91 Mg alloy was enhanced due to both the formation of polygonal Al2Y in AZ91 Mg alloy containing 1%Y and the formation of rod like Al4（Ce,La） in AZ91 containing 1%MM possessing higher thermal stability and microhardness.By friedel model,the critical stress σc for a dislocation moving from the resistant Y atom or Ce atom was calculated in both AZ91 containing 1%Y and AZ91 containing 1%MM alloy.The calculation reveals that the σc of die cast AZ91 containing Y is higher than that of die cast AZ91 containing MM,resulting in higher strength of AZ91 containing Y than that of AZ91 containing MM.关键词：Die Cast Mg Alloy;Y and Mistchmetal（MM）;Mechanical Properties at Elevated Temperature
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- 360
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发布时间：2023-12-18 - 摘要：Large end face of cover was choosed as the parting face of moving and static container based on the structure of brush cover and technology.The small formation holes in the brush cover was constructed with the mold core in moving and static container,and center ingate was employed to the gating system.Oblique tenon was adopted to draw core due to the short distance of drawing-core.关键词：Brush Cover;Die Casting Die;Center Ingate;Oblique Tenon Drawing-core
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- 98
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发布时间：2023-12-18 -
- 摘要：Application of Programmable Logica controller of Omron CPM2AE-60CDR-A instead of Koyo SR-20 in the J1116 horizontal cold chamber die casting machine was introduced.The system composition,implementation of software and hardware,transition between input and output interface as well as optimization of control system were focused on.
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- 100
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发布时间：2023-12-18 - 摘要：Fused quartz as refractory for shell-making was widely used in the United States.Fused quartz has features of low density,thermal expansion rate,good permeability and high creep resistance as well as easy mold-filling and shell-releasing.The merits and demerits of fused quartz and ZrO2 as refractory were compared.It was found that the fused quartz exists in reality and imminence for application in the investment industry due to its advantages of price and properties.关键词：Fused Quartz;Al-Si Refractory Materials;ZrO2;Shell-making
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- 365
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发布时间：2023-12-18 -
- 摘要：Slag and gas-hole easily appears on the surface of carbon steel investment casting due to high carbon content resulting in trapped-gas and heavily oxidation,majority in up-surface of the castings in assemble tree plan,so the appearance and quality of the casting were influenced.Liquid steel can be poured into shell mold through a set additional sprue to make the liquid steel stably raise in shell mold.And the produced gas and slag were smoothly floated from the casting accompanying with the liquid steel through the ingate,avoiding the occurrence of gas-hole and slag in up-surface of the casting in assemble tree plan and improving the surface quality,reducing the repaired cost.
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发布时间：2023-12-18 - 摘要：The chemical compossition and macrostructure of the cranksshaft for internal combustion engine with big diameter manufactured by electroslag multistep smelting-casting were investigated.Quaternary slag system,including CaF2（20%～30%）,Al2O3（20%～30%）,CaO（15%～20%）,MgO（15%～20%）,with low melting point and good fluidity was used,in which the hydrogen-removal was pretreated to prevent slag inclusion in welding-zone through improving the purity of slag system.The red copper was used for mould face.Cooling water pressure is more than 0.5 MPa,and flow velocity is more than 4 m/s,and the effluent temperature is less than 50 ℃.Flexible connection was applied for the mould to prevent the crack.The results showed that the crankshaft possesses uniformly composition and soundness microstructure,in which shrinkage porosity and segregation was remarkably decreased,and S content is decreasd by 60% and P content is decreased by 20%.The crankshaft with high toughness and strength can be obtained after annealingat 800 ℃.关键词：Consumable-electrode;Electroslag Casting;Multistep Molding;Pretreatment;Welding Zone
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- 134
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发布时间：2023-12-18 - 摘要：The process on characteristics of oxygen-free copper contact wire were studied. The results show that the resistivity of contact wire is effected by Fe evidently and will become unqualified when w（Fe） arrives at 20～30×10 -6 . S、H、O effect the strength and resistivity rarely, nevertheless, effect the Elongation evidently. The situation can be worse when w（S） is up to 38×10 -6 ,w（O） is up to 8×10 -6 or w（H） is up to 0.6×10 -6 . S content is dependent on the raw material-copper cathode. Fe, O, H content is dependent on the process.
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- 269
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发布时间：2023-12-18 - 摘要：Bimetal copper-cladding aluminum bars with different transition layers were manufactured by continuous casting.The composition of sample in which the core is composed of totally compounds and its reason were discussed based on the experiment.How to control the thickness of transition layer and improve the quality was further investigated on the basis of the above results.关键词：Bimetal in Continuous Casting;Copper-cladding Aluminum Bar;Transition Layer;Compound;Temperature;Drawing Velocity
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- 323
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发布时间：2023-12-18 - 摘要：Hypereutectic Al-6Si alloy and eutectic Al-12Si alloy were modified with Na respectively.It was found that the Na modification is failure with refusing without static magnetic field for the hypereutectic Al-6Si alloy,in turn with the static magnetic,Na modification keeps the effects.Eutectic Si was fined and showed a certain granularity under static magnetic field at holding time for 20 min for eutectic Al-12Si alloy,which indicated better modification effects than that without static magnetic field.Modification fades are heavy in the Al-12Si alloy without static magnetic field at holding time for 40min while slight with static magnetic field.The above results indicated that the static magnetic field can improve the modification effects.It is due to the fact that the static magnetic field can restrain the conversion.关键词：Static Magnetic Field;Al-Si Alloy;Modification;Eutectic Si;Re-fusion
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- 134
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发布时间：2023-12-18 - 摘要：Relationship of superheating degree,Mg content and hydrogen content in Al-Mg alloy was examined by measuring hydrogen content in Al-Mg alloy melt with different superheating degree and Mg content through HYSCANII.The results showed that hydrogen content increases with the increase of temperature in Al-Mg alloy melt.Different morphology of hydrogen in the melt can result in different reversibility.The hydrogen content in the melt can be greatly reduced by heat-speed treatment.Changes of Mg on surface oxidized film in aluminum melt are responsible for the hydrogen-absorption of Al-Mg alloy melt.关键词：Hydrogen Content;Super-heating Temperature;Heat-speed Treatment;Al-Mg Alloy
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- 381
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发布时间：2023-12-18 -
- 摘要：Effects of some key processing parameters including carbon nanotubes addition,temperatures and stirring time on preparation of carbon nanotubes reinforced Mg matrix composites in casting method were investigated by the orthogonal experiment and on the mechanical properties and microstructure of the composites were discussed.The results showed that the addition of carbon nanotubes （CNTs） can obviously refine the grain size and improve the tensile strength and elongation of the composites.CNTs has a significant effect on the mechanical properties of the composites among three processing parameters,and optimum mechanical properties of the composites can be obtained with 1% CNTs addition at 680 ℃ temperature for 3 min stirring time.关键词：Mg Composites;Carbon Nanotubes;Technology;Orthogonal Experiment
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- 410
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发布时间：2023-12-18 -
- 摘要：A new particulate reinforced Al matrix composites was successfully prepared by the direct melt reaction in system of Al-Zr（CO3）2-KBF4.XRD and SEM analysis indicated that the formed fine ZrB2,Al2O3 and Al3Zr particulate with average grain size of 80～90 nm uniformly dispersed in the matrix.Tensile test showed that tensile strength,150.3 MPa,for 70.0 MPa of the Al matrix,raised by 92.7%,and yield strength,112.4 MPa,for the 42.0 MPa of the Al matrix,raised by 170.7%,of the composites remarkably increased with the increment of the reaction system addition.The elongation of the composites rises first and fall later.SEM observation reveals that although the ductile area is reduced with the increase of reaction system,the fracture mechanism is dominated.关键词：Al-Zr-O-B System;Melt Reaction;Al Matrix Composites;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：SEM and XRD were employed to observe microstructure and phase constituent of TiN/Ti composites prepared by the smelting-casting method.The formation of TiN was analyzed.The results showed that continuous chain-like enhancement phase in the composites was uniformly distributed.SEM observation revealed that the morphology of TiN with the grain size of 2～8 μm is sharp angle sheet shape,sheet or bulk shape.There is no reacted layer between TiN particle and matrix interface.关键词：Ti Alloy;Composites;Microstructure;TiN;Smelting-casting Method
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发布时间：2023-12-18
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