最新刊期
卷 ， 期 10 ， 2008
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- 摘要：Effects of Ca and Zr addition on as-cast microstructure and mechanical properties of AZ31 magnesium alloy were investigated. The results indicate that the microstructure of AZ31 magnesium alloy can be refined with Ca addition, in which the precipitates at inter-crystal are increased and β-Mg17Al12 phases are decreased. In addition, the Al2Ca phase is created at grain boundary with 0.37% Ca addition, which can improve the tensile strength of alloy to maximum value of 190.3 MPa as a result of enhancing alloy. The minimum size of 63.4 μm can be obtained in the AZ31 alloy with 1.5% Ca addition. Zr addition can refine the microstructure and improve the mechanical properties of AZ31 magnesium alloy in electromagnetic-suspending casting. Compared with those of as-cast AZ31 magnesium alloy, the tensile strength and elongation of the alloy with 0.07% Zr addition are 210.75 MPa and 12.9%, respectively, increased by 19.56% and by 20.56%, respectively.关键词：AZ31 Magnesium Alloy;Ca;Zr;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Effects of quenching transferring time on the intergranular corrosion resistance of aluminum alloy containing Zr or free were observed by OM （optical microscope） and SEM （scanning electronic microscope）. The results reveal that with increasing in the quenching transferring time, the intergranular corrosion depth is increased, showing the fading of intergranular corrosion resistance of alloy. However, the intergranular corrosion resistance of the alloy containing Zr is superior to that of one free Zr. The increase of quenching transferring time results in widening grain boundary precipitate free zone, which is primarily responsible for the decrease of intergranular corrosion resistance. The Zr addition can increase intergranular corrosion resistance as a result of inhibiting recrystallization.关键词：Aluminum Alloy 7055;Quenching Transferring Time;Intergranular Corrosion Resistance;Grain Boundary Precipitate Free Zone
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发布时间：2023-12-18 - 摘要：Effects of the initial velocity of gas, the melting temperature and the melt flow rate of Al-12Zn alloy on the droplet size distribution and average solid fraction in different cross section of the spray cone were examined based on droplet solidification model coupled with droplet size distribution function. The results show that with increasing in initial velocity of gas, the average solid fraction in the same cross section of spray cone is increased, while it is decreased with increasing in melting temperature or in melt flow rate.关键词：Spray Forming;Spray Cone;Solidification;Simulation;Droplet
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发布时间：2023-12-18 - 摘要：Effects of extruded process, such as extruded temperature and cooling rate, and deformation rate on microstructure and properties of AZ31 magnesium alloy were investigated to optimize processing parameters. The results indicate that the mechanical properties and microstructure of the AZ31 magnesium alloy are relavant with to extruded temperature, deformation rate and cooling rate. Twin-crystal periodically exists in the structure of the AZ31 alloy during extrusion process, and it is helpful for the creation of twin-crystal in the structure with low extruded temperature and deformation rate as well as high cooling rate. Extruded force is decreased with increasing in extruded temperature, and the strength of the alloy can be improved with rising deformation rate in case of water cooling. Meanwhile, slight effects of varied extrusion parameters on electronic conductivity can be observed. The tensile strength and electronic conductivity of the alloy are 272.2 MPa and 17.3 MS/m, respectively, with extruding at 400 ℃ and extruding rate of 14.5 in the condition of water cooling .关键词：AZ31 Magnesium Alloy;Extrusion;Processing Parameters;Microstructure
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发布时间：2023-12-18 - 摘要：Modeling with gas-liquid two-phase flow was established based on a new interface tracking method-Level Set method to predict the filling process, which can overcome the shortcomings of conventional VOF method. The motion process of droplet and the air bubble was simulated by the model and was verified by hydraulic simulation. The simulated results are well in agreement with the experimental ones, showing the availability of the model.关键词：Casting;Filling Process;Numerical Simulation;Level Set Method;Two-Phase Flow
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发布时间：2023-12-18 - 摘要：The microstructure of eutectic ZL108 aluminum alloy prepared by single roller rotating-quenching method was observed by DSC（differential scanning calorimetry）, X-ray diffraction （XRD） and transmission electron microscope（TEM）. The results indicate that the only presence of Al diffraction peak can be observed in the diffraction spectrum of the rapidly solidified alloy, exhibiting the samller lattice constant compared with the conventional alloy. And the rapidly solidified alloy has more an exothermic peak than the conventional alloy in the DSC curves of heat flow-temperature before melting. TEM observation reveals that there exists hypoeutectic solidified structure without developed dendrite in the rapidly solidified alloy, which is composed of micron grain and eutectic area in which nanometer Si particle exists. It can be concluded that the alloy elements such as Si has almost fully dissolved into Al solid solution, resulting in the enlargement of dissolvability and the movement towards right of eutectic point, meanwhile, the microstructure of the rapidly solidified alloy is greatly superior to that of conventional alloy.关键词：Rapid Solidification;Eutectic Al-Si Alloy;Refinement;Microstructure
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发布时间：2023-12-18 - 摘要：Grain growth in aluminum strip during rolling was simulated by the cellular automaton method, in which the dendritic growth in super-cooled melt was considered based on simplified binary alloy by means of LGK model. Effects of cooling rate and super-cooled rate derived from rolling velocity on grain growth were simulated by the model. The results show that, with increasing in super-cooled rate, the grain size is increased at a given nucleation rate.关键词：Cellular Automaton;Grain;Aluminum Strip Undercooling
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发布时间：2023-12-18 - 摘要：Critical solid fraction of （CSF） Ti alloy melt is controlled by rotating velocity of the mould and rotating radius in vertical centrifugal field. The results indicate that critical solid fraction is gradually increased with increasing in rotating velocity of mould and rotating radius. Dynamic critical solid fraction in centrifugal field was established through a trial-calculation method. Meanwhile, effects of rotating velocity, rotating radius, melt super-heating degree and temperature of mould on shrinkage hole （porosity） were predicted by the numerical simulation method. The results reveal that with increasing in rotating velocity and rotating radius as well as melt super-heating degree and mould temperature, the shrinkage porosity（hole） is reduced.关键词：Vertical Centrifugal Field;Critical Solid Fraction;Shrinkage Hole;Shrinkage Porosity;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Effects of different pouring temperature and rotating velocity of rotating duct on microstructure of A356 aluminum alloy semi-solid slurry were observed based on the self-developed LSPSF technology. It is concluded that the desirable semi-solid slurry with spheroidized structure can be prepared successfully with rotating duct tilting angle of 20°at rotating velocity of 90150 r/min and slurry reserving container temperature of about 500 ℃ as well as pouring temperature more than （30±10） ℃ above liquidus temperature. The practical production verifies that LSPSF method has the advantages of high processing efficiency and stable performance, which can effectively realize the on-line preparation of A356 aluminum alloy semi-solid slurry.关键词：LSPSF;Aluminum Alloy;Semi-solid;On-line
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发布时间：2023-12-18 - 摘要：Preparation of A2017 semi-solid alloy was conducted by means of a new wave-like sloping plate method. The molten alloy was heterogeneously nucleated on surface of wave-like sloping plate and was grown in the condition of flow, collision and shearing, resulting in the gradual evolution of coarse net-work equiaxed grain into fine spheroid particle. The microstructure with fine uniform distribution in the semi-solid alloy can be successfully prepared with pouring at 720 ℃ on the interval wave-like sloping plate with length in 400500 mm and declined angle of 45°. Furthermore, the desirable spheroidized structure suitable for thixo-forming was obtained with re-heating at 625 ℃ for 60 min.关键词：A2017 Alloy;Wave-like Sloping Plate;Semi-solid;Microstructure
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发布时间：2023-12-18 - 摘要：Wrought aluminum alloy components could be produced by direct squeezing casting, whose mechanical properties are nearby those of forged components. However, the shape and surface of components are limited in direct squeezing casting. And the components exhibit higher crack tendency in conventional indirect squeezing casting so that it is difficult to produce complicated thin-walled component. Based on above analysis, it is an acceptable method to adopt double squeezing casting technology.关键词：Wrought Aluminum Alloy;Squeezing Casting;Double Squeezing Casting
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发布时间：2023-12-18 - 摘要：The purification mechanism of ceramic filter is as follows: obstruction, absorption and rectification effect. The foam ceramic filter exhibits excellent rectification effects in low pressure casting A356.2 aluminum alloy wheel, and the crack in the surface layer of the wheel can be greatly eliminated. In addition, the tensile strength, yield strength and elongation of the wheel keep stable by means of the foam ceramic filter as a result of removing inclusions in aluminum melt, avoiding the sharp deterioration of mechanical properties of the alloy resulting from a few coarse inclusions. However, the tensile strength and yield strength of the alloy can not be obviously improved due to the existence of fine inclusion. It is beneficial for the improvement of mechanical properties of the wheel with the foam ceramic filter due to the removal of the coarse inclusion in aluminum melt.关键词：Ceramic Filter;Purification;Aluminum Alloy Wheel;Low Pressure Casting;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Three kinds of squeezing casting processes for swashplate were designed according to the material, performance and machining requirements. The side-pouring indirect squeezing casting with holding pressure and localization pressurization was adopted for producing the swashplate for compressor of air conditionor for the car through comprehensively comparative analysis, such as the bubbling of the castings after heat treatment and inclusion, practical operation, yield production rate and production efficiency. The technology has the advantages of simplified mould structure, convenient operation, low casting defect in swashplate, high yield production rate as well as high product efficiency.关键词：Squeezing Casting;Aluminum Alloy;Compressor of Air-conditionor;Swashplate;Car
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发布时间：2023-12-18 - 摘要：Expanding-swelling defects often appeared in long-narrowed slot in investment casting. The defects can be eliminated or relieved by adopting ceramic core, however, the product cost would be increased with the difficult post treatment. Through analyzing practical defects in production, slurry-feeding method was proposed to eliminate the expanding-swelling defects in the castings. The practical production show that the method is very effective.关键词：Investment Casting;Expanding-swelling;Slurry-feeding
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发布时间：2023-12-18 - 摘要：Origination of deformation in investment casting thin plate was described. The deformation of thin plate can be effectively eliminated by adopting vertical welding assembling tree, which is superior to that of horizontal welding assembling tree due to large anti-bending modulus in cross section.关键词：Thin Plate;Horizontal Welding Assembling Tree;Vertical Welding Assembling Tree;Anti-bending Modulus
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发布时间：2023-12-18 - 摘要：Some kinds of gating systems were designed to produce a ring-thin-walled parts. Hot spot formed at congregation between rib and wall can obviously affect the shrinkage porosity （hole） defects in the ring-thin-walled parts. The shrinkage porosity （hole） defects in the castings can be obviously eliminated by multi-gating sketch with directly setting runner on the hot spot position, however, the production yield rate is slightly decreased.关键词：Thin-walled Parts;Hot Spot;Shrinkage Hole;Gating System;Production Yield Rate
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发布时间：2023-12-18 - 摘要：Effects of ZnO as additive on structure and properties of ceramic layer were investigated, and were compared with those of compound pipe with adding 4%SiO2+4%CaF2. The results indicate that the structure of ceramic layer is converted from arranged dendrite into fine equiaxed crystal and the density of ceramic layer as well as compressive strength of compound pipe are improved with ZnO addition. The density of ceramic layer and compressive strength of compound pipe are 4.520 g/cm3 and 406 MPa, respectively, with 6%ZnO addition, which are greatly superior to that of compound pipe with 4%SiO2 +4%CaF2 addition.关键词：SHS;Additive;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：As-cast microstructure of a high purity Al-Cu-Mg alloy was observed by XRD（X-ray diffraction） and SEM （scanning electron microscope）, and secondary phase in microstructure was analyzed by EDS（energy diffraction spectrum）. The results reveal that the microstructure is composed of α-Al, Al2Cu （θ） and Al7Cu2（Fe,Mn） phase. In addition, the composition design of Al-Cu-Mg series alloy was described based on phase diagram.关键词：High Purity Al Alloy;Al-Cu-Mg Alloy;As-cast Microstructure;SEM
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- 292
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发布时间：2023-12-18 - 摘要：Formation and effects of Al-Zr-Cr-La dispersoid in aluminum alloy were investigated. The results show that Al20Cr2La dispersoids are created in the alloy, which can evidently restrain the recrystalization and enhance the alloy, and Zr element can be dissolved into the Al20Cr2La phase in the alloy containing Zr. Compared with the Al20Cr2La phase without Zr, the Al20Cr2La phase with Zr exhibits higher capability of inhibiting recrystalization with slight improvement of enhancing alloy.关键词：Al-Zr-Cr-La Alloy;Al20Cr2La Phase;Dispersoid;Recrystalization;Enhancing Effects
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发布时间：2023-12-18 - 摘要：The morphology of inclusion that was increased with adding aluminum scrap in aluminum melt was observed by OM （optical microscope）, and the Tafel curves and the linear polarization resistance were measured to obtain the corrosion potential and corrosion current. The results indicate that, with the increase of aluminum scrap, the Tafel curves moves towards right, and the linear polarization resistance is decreased, and the corrosion potential moves towards negative as well as increasing in corrosion current. The regression model for describing relationship between inclusion content and electrochemical parameters was established based on the linear change of electrochemical properties with inclusion variation, meanwhile, the new way on electrochemical parameters characterizing inclusion in aluminum melt was proposed.关键词：Aluminum Alloy;Inclusion Measurement;Electrochemical Parameters;Polarization Curves
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发布时间：2023-12-18 - 摘要：Microstructure of A356 aluminum alloy refined by Al5Ti1B0.5RE master alloy was observed by OM （optical microscope）, SEM （scanning electronic microscope） and EDAX to understand the refining effects of the master alloy. The results indicate that the master alloy can greatly refine the grain size and dendrite in A356 aluminum alloy, in which the RE exhibits significantly positive role. AlTiRE phase formed in the master alloy with RE is unstable in Al melt it and could dissolved quickly into Al melt to release RE elements, which can decrease surface energy and tendency of segregation of TiB2 phase, increasing nuclei amounts. Meanwhile, RE can restrain the growth of TiAl3 phase and the formation of acicular TiAl3 phase as a result of RE easily segregating in grain boundary and phase interface of Al melt, raising the nucleation rate. In addition, RE can improve the refining effects of the master alloy due to effectively purifying the metallurgical quality of the master alloy and Al melt.关键词：Aluminum Alloy;AlTiBRE Master Alloy;Rare Earth;Grain Refinement
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发布时间：2023-12-18 - 摘要：The permanganate conversion coating on AZ91D magnesium alloy was prepared in a nitric acid-permanganate solution, and the corrosion resistant of the coating was examined by neutral salt spray testing（NSS） and polarization curves, and the adhesive forces of the conversion coating to organic coating were measured by lattice method. Meanwhile, the microstructure, constituent, structure and forming mechanism of the conversion coating were determined by SEM （scanning electron microscope）, EDS and XRD. It is found that the desirable corrosion resistance of the conversion coating that exhibits yellow and appears as cluster particles like deposits and is composed of Mn oxide can be observed at temperature of 40 ℃ for 120 s in 3.5 g/L KMnO4 solution with pH value of 4.0, which is greatly superior to that of the magnesium alloy substrate. In addition, the adhesive grade to iron red paint reaches up to 3B.关键词：Magnesium Alloy;Chemical Conversion Coating;Permanganate;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：Magnesium alloy as an alloy material with active chemical properties easily lead to burning and explosion in process of smelting-casting and post-treatment procedure. The potential safety problem in process of smelting-casting was systematically expounded based on special features of Mg alloy, and the accident condition was approached. Meanwhile, safety production management specification, operation safety procedure and equipment safety requirement were proposed.关键词：Magnesium Alloy;Safety;Countermeasures;Smelting-Casting
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发布时间：2023-12-18 - 摘要：Silver films were made by thick film method with ultrafine silver powders prepared by DC（direct current） arc plasma evaporation. Effects of slurry compositions on the properties of the silver conductor with thick film had been investigated by varying proportion of slurry composition with the help of OM, EDS. The results indicate that the slurry viscosity is increased with the increase of solid phase content, and the optimized solid phase content is 80%. At the experimental range, the sheet resistance of the sintered thick film is firstly decreased, then increased with increasing in glass powder content, and desirable glass content is 3%. In addition, sizes of glass powder and Ag powder have evidently affected the properties of Ag conductor slurry. There exists a desirable match in Ag powder and glass powder for conductivity. The Ag powder with average size of 102.92 nm and 204.26 nm exhibits good solderability, and size of glass powder also affects the solderability of silver conductor with thick film to some extent.关键词：Ultrafine Silver Powder;Thick Film Conductor Slurry;Properties
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发布时间：2023-12-18 - 摘要：Effects of soldering processing parameters on the growth of interface intermetallic compound and shearing strength of Sn-2.5Ag-0.7Cu-0.1RE/Cu soldering joint were investigated by SEM （scanning electron microscope） and XRD（X-ray diffraction）. The results indicate that wave-like Cu6Sn5 phase is created at the interface of the soldering joint after soldering. With extending soldering time and increasing soldering temperature, wave-like Cu6Sn5 phase is converted into scallop-like structure with bigger size, which results in the increase of thickness and interface roughness. Cu6Sn5 phase with 2.2 μm in thickness and 1.26 μm in roughness can be generated with soldering at 270 ℃ for 180 s, which is responsible for the highest shearing strength of soldering joint.关键词：Soldering Technology;Sn-2.5Ag-0.7Cu-0.1RE/Cu;Interface Intermetallic Compound;Soldering Joint;Shearing Strength
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发布时间：2023-12-18 - 摘要：Effects of aging temperature and aging time on microstructure and properties of Cu-2Ni-0.5Si alloy were investigated after varying cold deformation. The results indicate that the secondary phase is dispersively distributed in the alloy with solid solution at 900 ℃ and then aging treatment after varying cold deformation. The micro-hardness and electronic conductivity of the 80% deformed alloy with aging at 500 ℃ for 1h are 250 and 22.625 MS/m, respectively, exhibiting higher comprehensive properties compared with those without cold deformation. Pre-cold deformation before aging can strongly accelerate the precipitation of secondary phase in the alloy during aging, which is responsible for the improvement of micro-hardness and electronic conductivity. The tensile strength of the 40% pre-cold deformed alloy with aging at 450 ℃ for 4 h can reach up to 620 MPa, and the fracture morphology is characterized by typical ductile fracture mode.关键词：Cu-2.0Ni-0.5Si Alloy;Aging;Cold Deformation;Micro-Hardness;Electronic Conductivity
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发布时间：2023-12-18 - 摘要：Effects of low frequency electromagnetic field on ingot surface, as-cast microstructure and alloying element distribution in horizontal continuous casting aluminum alloy slab were investigated, which was compared with that of conventional horizontal continuous casting aluminum alloy slab. The results reveal that low frequency electromagnetic field can greatly improve the as-cast microstructure of horizontal continuous aluminum alloy slab. The uniformly distributed fine as-cast microstructure in the cross section of the whole ingot can be observed as a result of refining grain size and weakening the effects of gravity on solidification process of ingot by low frequency electromagnetic field. In addition, the solute element is more homogeneously distributed in the cross section of the slab, which is resulted from reducing negative segregation and gravity segregation by low frequency electromagnetic field.关键词：Low Frequency Electromagnetic Field;Aluminum Alloy;Continuous Casting;As-cast Microstructure
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发布时间：2023-12-18 - 摘要：Origination of sand flushing in EPC（evaporate pattern casting） was analyzed by mathematical theory. The sand flushing defects between the sprue and pouring cup in EPC can be prevented by preventing sealed plastic film from high temperature heat sources and by sealing joint of pouring cup and the sprue with refractory mortar containing high temperature binder to take a whole shape. The sand flushing defects in bottom of the sprue can be eliminated by sealing around refractory brick for bottom of the sprue refractory mortar. The sand flushing in the sprue and in runner as well as in joint between ingate and runner can be prevented by thickening coating on the ingate , sealing joint with the refractory mortar or brushing rapidly drying coating as well as drying wet sand and vacuum pumping ahead of 35 minutes.关键词：EPC;White Defects;Prevention
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发布时间：2023-12-18 - 摘要：<正>神人纹双鸟鼓[1]（见下页）商代（公元前17世纪—前11世纪）晚期锡青铜高79.4cm日本泉屋博物馆藏鼓的用途多见于两周典籍。《诗经·小雅》:"琴瑟击鼓,以御田祖",意思是击鼓为乐,迎田祖以祈丰年。《周礼·地官·鼓人》:"掌教六鼓四金之音声,以节声乐,以和军旅,以正田役",说明鼓又可作为军队在作战时与田
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发布时间：2023-12-18 -
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