最新刊期
卷 ， 期 12 ， 2006
- 摘要：Effects of solidification structure and solidified rate on structural morphology, interfacial temperature and phase constituent of Cu-55Sn hypo-peritectic alloy have been investigated with directional solidification rate in the range of 0. 5-100μm. The results show that directional solidified phase constituent is composed of primary ε phase, peritectic rj phase and eutectic （η+Sn） phase. Bulky peritectic rj phase is embedded in primary e phase in the directional solidification Cu-55Sn hypo-eutectic alloy with directionally solidified rate in the range of 0. 5μm/s while with solidified rate more than 5 μm, the solidification structure remains the conventional plate structure, where peritectic rj phase coats primary e phase. Coupled growth in isothermal interface for peritectic rj phase and primary εphase can not be formed because primary e phase is prior phase, which is in accordance with analysis of top-interface temperature growth theory. Major peritectic η phase is directionally formed from the liquid phase during direction solidification process. In addition, with increasing in cooling rate and decreasing in solidification time, peritectic rj phase content is firstly increased then decreased, and the peak content of the peritectic rj phase can be observed with the directional solidification rate of about 10 μm.关键词：Cu-55Sn Hypo-peritectic Alloy;Directional Solidification;Phase Content
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发布时间：2023-12-18 - 摘要：Factors influencing purification of molten aluminum alloy by electro-flux have been investigated byorthogonal testing. Optimized processing parameters and remarkable characters among different influential factors were determined by range analysis and variance analysis of experimental data using inclusion contents in molten aluminum as referent index. Meanwhile, the purified mechanism of electro-flux has been approached. The results show that the dominant factor influencing purified effects is flux thickness. The optimized processing parameters are as follows: flux thickness of 30 mm, liquid aluminum diameter of 7 mm, current of 15 A and refining temperature at 700℃.关键词：Molten Aluminum;Electro-flux;Inclusion;Orthogonal Testing
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发布时间：2023-12-18 - 摘要：Microstructure, interfacial morphology and mechanical properties of H90/steel/H90 cladding strip in inversion solidification have been investigated, and the bonding mechanism on interface has been expounded. The observation of optical microscope （OM） and scanning electron microscope （SEM） indicate that the microstructure in H90 cladding is composed of equi-axed grain, and the microstructure change of steel strip has not been observed before and after cladding, and interface layer with 4μm in thickness is generated, in which the diffusion of Cu and Fe into interface and the diffusion-absent of Zn have been observed. Bending test and multi-pass small-reduction cold-roll show that the interface of cladding strip is firmly bonded. Tensile test shows that although there exists slightly difference in mechanical properties among the cladding strips with varied cladding thickness, all them can meet the requirements of GB5213-85 for F-grade deep-drawing steel sheet.关键词：Inversion Solidification;Cladding Strip;Bonding Interface;Mechanical Properties;Metallurgical Bonding
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发布时间：2023-12-18 - 摘要：Effects of different yttrium contents , such as 0, 0. 1%, 0. 3%, 0. 5%, 0. 7%, 1. 0%, on micro-structure and tensile strength at room temperature of Ti-47Al-xY alloy have been investigated systematically. The results show that with the increase of yttrium content, the columnar crystal in alloy is changed into equiaxed crystal with the yttrium content more than 0. 3%, and the grain size and lamellar space are decreased remarkably. With yttrium content more than 0. 1 % , when fine YA12 particle is uniformly distributed in the grain, some YA12 particles begin to segregate from the boundary in the alloy. Furthermore, the segregation from boundary becomes more and more serious with increasing in Y content. YAl2 phase is closed to form network with 1% Y content. Tensile testing indicates that the Ti-47A1 alloy with 0. 3% -0. 5% Y content possesses higher strength and plasticity. Size and distribution of YA12 phase in the alloy has the significant effects on properties of the alloys. As fined microstructure and fine YA12 phase in the grain is beneficial to improving the properties of the alloy, large YA12 phase enriched in boundary can greatly deteriorate the properties of TiAl alloy, especially Y content more than 0. 5%.关键词：TiAl;Microstructure;Tensile Strength;yttrium
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发布时间：2023-12-18 - 摘要：Rolling process of spray deposited SiC particulates reinforced Al-8. 5 Fe-1. 3 V-1. 7 Si aluminum sheet has been investigated. The density change and mechanical properties during the rolling process at ambient temperature were examined, and its microstructure was observed by SEM and TEM. It is found that the compactness, rolling temperature and pass reduction play a significant role in rolling properties of the composites. The composites with tensile strength of 35 MPa and elongation of 7% can be obtained by optimizing rolling processing parameters.关键词：Composites;Spray Deposition;Heat Resistant Aluminum Alloy;Rolling
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发布时间：2023-12-18 - 摘要：We have developed a method with auxiliary e-quipment to prepare bulky amorphous alloy by suction casting with copper mould under non-vacuum melting conditions, in which high pure argon flow was employed to protect melting of’alloy, and then the glass melt is introduced into a copper mould to rapidly form a sample or a part through a tube based on negative pressure. The Mg65Cu25Y10 amorphous alloy rod with diameters of 3 mm has been prepared successfully with commercial raw materials using the method. Compared with the other preparing methods, the method has the features of low equipment cost, simple process and convenient operation.关键词：Negative Suction Casting with Copper Mould;Preparation;Bulky Amorphous Alloy
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发布时间：2023-12-18 - 摘要：Effects of nano-filler on strength of the epoxy adhesive have been examined by adding the nano-filler into the epoxy adhesive. The results show that the tensile strength and shearing strength of the epoxy ad-hesive（E44,E51） are 69.09 MPa and 35.86 MPa. respectively, with the addition of nano-SiO2 particles and one-dimensional nano-SiC whisker. The desirable mechanical properties of the epoxy adhesive can be realized with the addition of 7% nano-SiO2 particles and 10% one-dimensional nano-SiC whisker.关键词：Epoxy Adhesive;Nano-filler;Strength;Whisker
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发布时间：2023-12-18 - 摘要：A three-dimensional grid model was established to simulate filling process of the rudder in squeezing casting based on practical rudder dimension and technique design, in which relevant boundary conditions were considered. Simulated results show that the converging point of pressure flow and reflect flow in filling process in squeezing casting lies at the top right sides of the rudder, accompanying with the appearance of turbulent flow and entrapped-gas. The practical produced rudder shows that its top right sides are a place where most casting defects occur. Simulated results are well in agreement with practical ones.关键词：Squeezing Casting;Grid Model;Boundary Conditions;Simulation
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发布时间：2023-12-18 - 摘要：By using the software Flow-3D, the filling process for aluminum alloy valve cover in die casting and oxides inclusion in ones were simulated. Based on the simulated results, the gating system was optimized to effectively eliminate oxides inclusion in aluminum alloy valve cover. Ingate position has greatly affected the filling morphology and oxides inclusion. Optimization of gating system can reduce inclusion and be favorable for improving castings quality. Computer simulation can provide a reference for evaluation and optimization of gating system.关键词：FLOW-3D;Die Casting;Filling Simulation;Oxides Inclusion
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发布时间：2023-12-18 - 摘要：Simulation of filling process in semi-solid aluminum alloy A356 bracket thixo-casting was carried out by means of special thixo-forming function module in Any-casting software. Simulated results show that filling process is smooth in thixo-forming process and temperature field is uniformly distributed with pouring temperature at 590 ’C and filling velocity of 5 m/s, which is favorable for decreasing entrapped-gas and misrun and improving the quality of thixo-forming bracket.关键词：Numerical Simulation;AnyCasting;Semi-solid Forming;Pouring Temperature;Filling Velocity
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发布时间：2023-12-18 - 摘要：In the reheating process, the relationship between the reheating current, time and billet temperature must be strictly controlled to obtain the uniformly distributed temperature and spheroidized microstruc-ture in the billets. The reheating process for A356 a-luminum alloy was conducted with main frequency induction furnace. The results verify that rod billet with 45mm in diameters and 70mm in height can reach de-sirable state to meet the next process using the coilwith 70mm in diameters and 100mm in height throughthree stages reheating and holding time for about 10min.关键词：Semi-solid;A356 Alloy;Reheating
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发布时间：2023-12-18 - 摘要：The influence of low rotary frequency electromagnetic stirring on solidification structure of austensitic stainless steel in horizontal continuous casting has been examined based on industrial experiment. The results show that appropriate electromagnetic stirring parameters can obviously improve the macrostructure of austensitic stainless steel, in which columnar grains and equiaxed grains can be greatly refined and center shrinkage hole and shrinkage porosity can be remarkably decreased due to eliminating intracrystalline and enlarging equiaxed grain scope. Industrial trials reveal that the electromagnetic stirring intensity for austensitic stainless steel should be higher than that for conventional steel series. Electromagnetic stirring has somewhat affected the microstructure of the austensitic stainless steel with frequency of 3- 4 Hz even if the center magnetic induction intensity of the electromagnetic stirring reaches average 90mT （amplitude reaches 141 mT）, which provides a reference for the optimization of processing parameters.关键词：Horizontal Continuous Casting;Austensitic Stainless Steel;Electromagnetic Stirring;Equiaxed Grain;Center Shrinkage Porosity
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发布时间：2023-12-18 - 摘要：Based on the features of more than 40 blades and existence of hole in center and indentation in side in AlSil2Cu pump wheel, maximum cross-section was set as parting surface, which is favorable for die-release and manufacturing, and J1125G horizontal cold chamber presser with closing force of 2500 kN was determined. In the die structure, side-pouring gatingsystem and over-flow-exhausting system as well as 31 ejection pins with various sectional shape have been considered. In addition, two-half ring-core and two side-core-pulling mechanisms have been designed due to the existence of ring-indentation.关键词：Pump Wheel;Gating System;Ejection Pin;Core-Pulling Mechanism
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发布时间：2023-12-18 - 摘要：The effects of die structure on hot tear tendency of Al-Cu alloy in squeezing casting have been investigated, and the feeding mechanism of dross trap used for hot spot in die in squeezing casting has been discussed. Experimental results reveal that dross trap can effectively feed hot spot position when the solidification modulus of dross trap is more than that of adjacent hot spot position, which can significantly reduce the hot teat tendency of parts. The hot tear rate in the experimental parts is decreased from 27% （before die structure modified ） to 6% （after modified, such as enlarging dross trap）.关键词：Squeezing Casting;Al-Cu Alloy;Hot Tear;Dross Trap
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发布时间：2023-12-18 - 摘要：We have developed a vacuum directional solidification device to prepare multi-crystalline silicon ingot using metallurgical-grade silicon. Microstructure and purity of the multi-crystalline silicon have been observed by OM （optical microscope） and inductive coupled plasma spectrumer. The results show that the microstructure of ingot exhibits coarse columnar crystal and the purity of multi-crystalline silicon can be increased from 99. 50% to 99. 86%, in which various impurities are reduced slightly.关键词：Vacuum Induction Smelting;Directional Solidification;Multi-crystalline Silicon
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发布时间：2023-12-18 - 摘要：Large aluminum alloy parts easily formed cldshut and misrun as a result of difficultly controlling wall-thickness to result in the dimensional deformation and large aluminum alloy parts, such as sleeve, cap, ring,sheet, box, were described by considered dimensional control, deformation prevention, filling process and feeding ways.关键词：Aluminum Alloy;Large Normal Parts;Processing Design
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发布时间：2023-12-18 - 摘要：Effects of Sn on microstructure and mechanical properties of AZ61 magnesium alloy have been in-vestigated. Microstructural observation indicates that the spheroidal Mg2Sn particle is created in both as-cast and heat treated AZ61 alloy with Sn addition. A few Sn addition can increase the tensile strength and yield strength of the alloy. With 3% Sn addition, the tensile strength and yield strength of heat-treated AZ61 alloy can reach 274 MPa and 172 MPa, respectively, while elongation is decreased to 9%. With Sn addition, fracture morphology is transformed from cleavage rupture into quasi-cleavage rupture from SEM observation.关键词：AZ91 Magnesium Alloy;MgjSn;Micro-Structure;Mechanical Properties
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- 397
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发布时间：2023-12-18 - 摘要：Effects of thermal plastic deformation on microstructure and mechanical properties of eutectic Al-Si alloy have been investigated. The results show that tensile strength of as-cast alloy after thermal plastic deformation can be improved from 205 MPa to 260 MPa and its elongation can be increased from 3. 2% to 10% , which is attribute to spheroidize eutectic Si particle and solder shrinkage hole and shrinkage porosity. Moreover, tensile strength of the alloy can be increased from 292 MPa to 397. 4 MPa, and elongation can be raised from 0. 5% to 6. 5% after heat treatment.关键词：Aluminum Alloy;Plastic Deformation;Squeezing Ratio
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- 300
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发布时间：2023-12-18 - 摘要：Morphology transformation of eutectic silicon in Al-Si alloy during solid solution was observed by OM and SEM. The results show that the granulation effect of silicon phase is obviously controlled by the cast structure of eutectic silicon and the modification can greatly promote the granulation of silicon phase during the solid solution treatment. The modified and unmodified eutectic silicon phases have different 3D morphologies after solid solution treatment, in which the former is granular and the latter is lathy. Some phenomena in the morphology transformation of eutectic silicon and their mechansims were approached.关键词：Cast Al-Si Alloy;Eutectic Si;Solid Solution;Granulation;Modification
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- 607
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发布时间：2023-12-18 - 摘要：Severe-area black-face and concave scar often appear in surface of the investment castings, especially stainless steel castings, using shell mold made of ZrO2 as face layer and kaolinite refractory as back layer, which is severely detriment to the quality of the investment castings. Chemical properties and formation of defect position have been analyzed by energy diffusion analyzer based on worksite investigation. It is revealed that surface scar in the castings is remarkably relevant to the ink-point in shell-mold, and the blackface is composed of spinel complicated compound, which is created by reaction between Fe2O3 in face-layer and different metal oxidizer from oxidation on surface of castings. Based on above mentioned analysis, the counter-measures eliminating these defects were expounded.关键词：Investment Casting;Surface Defects;Fe-SiO3
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发布时间：2023-12-18 -
- 摘要：Sand mold copper alloy parts in low pressure casting with coke furnace were conducted based on woke-site practices. Sand with Fe ball was used as face-sand at thick-wall to accelerate the cooling of liquid copper alloy, and lift tube and mould was separated by asbestos gasket to prevent lift tube and mould from together. Holding pressure time was determined by measuring surface temperature change of liquid copper alloy with thermo-couple. Based on above men-tioned techniques, product-volume middle-small copper alloy parts could be produced in low pressure casting with coke furnace using the horizontal chain method, greatly improving the production efficiency.关键词：Low Pressure Casting;Coke Furnace;Copper Alloy Parts
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发布时间：2023-12-18 - 摘要：Effects of Ce2O3 addition in sulfate bath on microstructure and mechanical properties of electroforming layer on plastics-suction copper mould in electro-forming have been investigated. The results reveal that addition of Ce2O3 into sulfate bath can not only slow the deposited speed but also refine the grain size in the microstructure of electroforming layer on the copper mould, and compact the microstructure as well as improve micro-hardness and wear resistance of electroforming layer.关键词：Electroforming;Mould;Ce2O3 Particle;Microstructure and Properties
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发布时间：2023-12-18 - 摘要：Microstructure of as-cast, forged and solid solution treated CuCr25 contact materials prepared by atmospheric casting in main frequency induction furnace have been observed by scanning electron microscope （SEM）, and effects of aging treatment and deformation rate on electric conductivity and micro-hardness of the contact materials have been examined. The results show that the Cr phase can be distributed uniformly into the forged CuCr25 alloy. The alloy exhibits higher electric conductivity and micro-hardness with aging at 440 ℃ for one hour after solid solution at 950 ’C for one hour, while the electric conductivity and micro-hardness of 40% cold deformed alloy can reach 33. 1 MS/m and 174, respectively, after solid solution treatment with aging at 440 *C for two hours, increased by 5. 8 MS/m and 27, respectively, compared with those of the alloy after solid solution treatment with direct aging.关键词：Solid Solution;Deformation;Aging;Electric Conductivity;Micro-Hardness
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发布时间：2023-12-18 - 摘要：In-situ ZrBL, ZrAla and A12O3 particle reinforced aluminum matrix composites were prepared by the direct melt reaction in the system AI-Zr-O-B. The calculation of reactive thermo-dynamics of in-situ synthesized （ Al2O3 + Al2O3 + ZrB2） p/ Al composites shows that the reaction can self-proceed in the aluminum melt at initiating condition of 850 C. The observation of X-ray diffusion （XRD） and scanning electron microscope （ SEM） demonstrates that formed reinforced particles Al2O3,Al3Zr, ZrB2 are uniformly distributed into the composites. With the increasing in volume fraction of reactive particle, the tensile strength of the composites is raised and its elongation is descended.
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发布时间：2023-12-18 - 摘要：Influence of Sb on microstructure of 20 Mg2Si/Al-Si composites has been described. The results show that with the increase of Sb addition, primary Mg, Si phase is remarkably refined, in which chi-nese script or dendritic Mg2 Si phase is converted into uniformly distributed fine particle, and the volume fraction of Mg2Si phase is slightly increased. The optimum particle appearance and refinement can be obtained with about 0. 1% Sb addition, where the size of Mg2Si phase is refined to 25 μm from 52μm. However, excessive Sb content can results in coarsening par-ticle, which means the excessive Sb can detriment the refinement effects. The refinement of Mg2Si phase can be attributed to heterogeneous nucleation resulting from AlSb compound, meanwhile, Sb can decrease liquidus temperature and molten surface tension, which refines the Mg2Si phase to a certain degree too.
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发布时间：2023-12-18 - 摘要：TiAl-based composites were fabricated by an exothermic dispersion method in Al-Ti-TiO2 Nb205 system, whose reactive process is analyzed by differential thermal analysis （DTA） and thermo-dynamics calculation. The results show that Al-Ti reaction and Al-TiO2 reaction can be observed after Al melted at 721℃ , where the latter is completed before TiAl3 phase formed due to its faster reaction rate. Then, a complex multi-stage reactions is performed between Al and Nb2O5 with increasing temperature from 721℃ to 810℃. Then, an evolved reaction of TiAl,, to TiAl to Ti3Al phase is generated, which is controlled by solid atom diffusion at 810 ’C. Based on the exothermal reactions, much heat is released to accelerate the process of the whole system. Thermo-dynamics calculation verifies that creation of primary TiAl3 is prior to that of TiAl phase and Ti3Al phase, and the reaction between Al and Nb2O5 is finished by the formation of NbAl3 phase. A duplex structure consisting of the laminar phase containing α2 + γ can be obtained, in which reinforced Al2O3 phase distributed in interface is in stable state.关键词：Differential Thermal Analysis;Thermo-dynamics Calculation;Composites
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发布时间：2023-12-18 -
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