最新刊期
卷 ， 期 8 ， 2008
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- 摘要：The hot deformation behavior of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy was investigated with THERMECMASTOR-Z tester at strain rates of 0.001 s-170 s-1 at temperature of 7801 080 ℃, obtaining the flow stress data at varied temperatures and varied strain rates as well as different true strain. Based on experimental data and neural network knowledge, a BP neural network with error-back propagation algorithm was established, which forms a knowledge-based constitutive relation model after training. The flow stress in the alloys was predicted by the BP neural network model. The results show that the predicted results are well in agreement with the experimental ones,confirming the availability of the model.关键词：Ti-6.5Al-3.5Mo-1.5Zr-0.3Si Alloy;BP Neural Network;Constitutive Model;Flow Stress
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发布时间：2023-12-18 - 摘要：The homogeneous immiscible Al-Bi alloy was successfully prepared by a cooling slope method in which immiscible alloy was heated over the miscible temperature and then poured into a water bathed copper mould. The acted force of precipitated Bi-rich phase was described during flowing with melt on cooling slope. The results indicate that the Marangoni force, melt drag force and melt flushing force as well as gravity which acted on the Bi-rich phase are acted each other, resulting in the great reduction of the Stokes sedimentation and the Marangoni displacement, which plays significantly positive role for the homogeneous distribution of immiscible Al-Bi in cooling slope. Meanwhile, the temperature of the Al-Bi melt can be remarkably decreased after flowing slope, obviously decreasing the cooling pressure of water bathed copper mould, which have the positive effects of preparation of homogeneous immiscible Al-Bi alloy also.关键词：Immiscible Alloy;Al-Bi Alloy;Homogeneous Preparation;Cooling Slope
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发布时间：2023-12-18 - 摘要：Effects of electromagnetic stirring combining with refiner modification on microstructure of Al-Mg-Mn alloy were observed by SEM （scanning electron microscope）, XRD （X-ray diffraction）. The results reveal that the grain size in the alloy is obviously refined by electromagnetic stirring. The refiner has positive effects on the structure in the alloy in process of electromagnetic stirring, where the grain size becomes more and more refine with increasing in refiner addition and desirable grain size in the alloy can be observed with 0.1% refiner addition. Refining mechanism of electromagnetic stirring was approached by continuously temperature-measuring during solidification process of alloy in mould with refractory materials. It is believed that the electromagnetic stirring results in the appearance of forced convection in the melt and therefore promote the formation and fragmentation of nuclei, which are responsible for the refinement of grain size in the alloy.关键词：Electromagnetic Stirring;Refiner;Cooling Rate;Microstructure;Aluminum Alloy
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发布时间：2023-12-18 - 摘要：Ni-Al2O3 nano-composite coating with high Al2O3 particles concentration was prepared by the electrophoretic-electrochemical deposition. Firstly, a uniform Al2O3 particle coating with an average size of 20 nm was deposited on a copper substrate by the electrophoretic method, then Ni was deposited into the substrate with Al2O3 particle coating by the electro-chemical method, finally the Ni-Al2O3 nano-composite coating with 55.6 Al2O3 particle in volumetric fraction were prepared successfully. Surface morphology and adhesive strength of the coating were examined. Compared with the pure Ni coating, the nano-composite coating exhibits more refine grain size with compact and uniform microstructure as well as higher adhesive strength.关键词：Composite Coating;Electrophoretic Deposition;Electro-deposition;Adhesive Strength
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发布时间：2023-12-18 -
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- 摘要：Sb and RE mixed modification on Al-7Si-0.3Mg alloy has been performed. It is found that Sb and RE mixed modification can greatly refine the eutectic phase in the alloy, in which the twinned or fibrous Si phase can appear with the RE addition. Differential thermal analysis indicates that compared with that in the untreated alloy, the precipitated temperature of eutectic Si phase from the alloy treated by Sb or RE or SB plus RE mixed modification is obviously declined. The precipitated temperature of eutectic Si phase in the alloy modified by 0.15% RE is decreased by 7 ℃ with cooling at 50 ℃/min, that modified by 0.15% Sb is decreased by 5 ℃, and that modified by 0.15% Sb plus 0.15% RE is nearby to that by 0.15% Sb modification. The Sb plus RE mixed modification effect is superior to that of Sb or RE only, which is attributed to Sb promoting the nucleation and refinement of eutectic Si phase and RE resulting in the generation of twinned and fibrous eutectic Si phase. The mechanical properties of the alloy modified by Sb plus RE are greatly improved, especially the elongation.关键词：Al-7Si-0.3Mg Alloy;Sb and RE Mixed Modification;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Safe problems in manufacturing of foam magnesium alloy by vacuum infiltration were approached. The reasons of burning and explosion of magnesium alloy during vacuum infiltration were analyzed, and the countermeasures were proposed. The results indicate that the burning of magnesium alloy after infiltration is related to the material of mould, pouring temperature, pre-heated temperature of mould and preforms. The burning possibility of magnesium alloy after infiltration can be effectively decreased with using permanent mould, strictly controlling pouring temperature and pre-heated temperature of mould and preforms. The explosion of magnesium alloy melt during infiltration is closely related to the reaction of the melt with H2O or O2, so the explosion of magnesium alloy melt can be avoided by modifying experimental devices and strictly controlling H2O content during infiltration.关键词：Vacuum Infiltration;Foam Magnesium Alloy;Safe Problems
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发布时间：2023-12-18 - 摘要：Effects of different proportion between manganese and iron （w（Mn）/w（Fe）=0, 0.5, 0.8, 1.1 and 1.4） on the morphology of Fe phase and mechanical properties of ZL102 alloy with 1.2% Fe content were investigated. The results show that iron phase with coarse needle-like shape in the microstructure is observed, and it is converted into Chinese script with Mn addition. Furthermore, the Chinese script iron phase in the microstructure is increased and the needle-like iron phase is decreased and refined with raising Mn via Fe ratio. However, the mechanical properties of the alloy are deteriorated with the increase of Mn via Fe ratio as a result of increasing in Fe phase in the alloy. Meanwhile, both tensile strength and elongation of alloy exhibit the tendency of first rise then decrease with w（Mn）/w（Fe） ratio increasing. The optimized values of tensile strength and elongation, 157.7 MPa and 1.22%, respectively, can be obtained with w（Mn）/w（Fe） of 1.1.关键词：Al-Si Alloy;Mn via Fe Ratio;Iron Phase;Sr
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发布时间：2023-12-18 -
Spinodal Decomposition Structures in Diffusion Layer of Aluminized Steel and Its Formation Mechanism
摘要：Microstructure and composition of diffusion layer of the hot dip aluminized steel after diffusion at 850 ℃ for 4 hours were investigated by TEM （transmission electron microscope）. The results show that spinodal decomposition phenomenon is observed in Fe2Al5 and FeAl2 phases in diffusion layer. The pattern of spinodal decomposition structure is involved from parallel beeline to parallel across striation and then to lattice shape from the surface to inner of diffusion layer. There exist obvious effects of grain boundary on spinodal decomposition structure in some area of diffusion layer. In addition, there exist different spinodal decomposition structures in every grain. The stripes of the spinodal decomposition structure exhibit lamellar structure in inner in whole crystal. The formation mechanism of the spinodal decomposition structure was described based on the 15% rule.关键词：Aluminized Steel;Spinodal Decomposition;Formation Mechanism;Grain Boundary- 2
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发布时间：2023-12-18 - 摘要：The knockability of modified silicate sand was researched. Heating specification and cooling ways for measuring residual strength of silicate sand specimens were mapped. Knockability of 18# modified silicate sand was evaluated by means of residual strength value less than 0.5 MPa as a criterion. The results show that the CO2 modified silicate sand exhibits acceptable knockability with 2.5%4.0% binder addition at 4001 000 ℃. Residual strengths of common and modified silicate sand are measured at 200,600, 800,1 000, 1 200 ℃. It is found that peak residual strength appeared at 800 ℃ in both common silicate sand and modified silicate sand A1, and valley value appeared at 800 ℃ in both 18# modified silicate sand and modified silicate sand B2. The forming mechanism was approached.关键词：Sodium Silicate Sand;Modification;Knockablity
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发布时间：2023-12-18 - 摘要：The 140 mm×10 mm×3 mm laser rapid prototyping Fe-based thin plate containing various Co contents were produced by the ways of off-axis powder feeding, and then the thin plate was treated by heat treatment. The results show that the absence of crack and gas-hole in the laser cladding Fe-based thin plate can be observed, showing acceptable formality. The structure of the thin plate is composed of multi-layer structure with the same features, in which every layer structure consists of parallel dendrite that is perpendicular to the base plate and the interdendritic compound. Hardness and shearing strength of the cladding can reach up to the maximum values of HV37 and 461 MPa, respectively, with 3% Co content as a result of Co promoting the growth of dendrite and the refinement of the interdendritic compound. However, hardness and shearing strength of the plates are decreased after heat treatment due to the decrease of the solution element content. Alternatively, the hardness and strength of the plates are higher than those of 300 ℃ temper, which is attributed to the refinement of structure and new phase precipitation from the structure in the plate after 1050 ℃ quenching plus 600 ℃ tempering.关键词：Laser Cladding;Heat Treatment;Microstructure;Hardness;Shearing Strength
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发布时间：2023-12-18 - 摘要：According to structure features of torch parts, four die-casting processes were designed by Pro/E software and Z-Cast software. The potential defects position in the torch parts were predicted by simulating the filling process of four kinds of die casting sketches to optimize the die casting process. The results show that the visualization technology can improve the design efficiency in die casting process and reduce the cost of mould design and manufacturing.关键词：Pro/E;Z-cast;Die Casting;Optimization;Visualization
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发布时间：2023-12-18 - 摘要：The complicated magnesium alloy bullet supporter was manufactured by semi-solid extrusion method based on isothermal extrusion technology, in which semi-solid magnesium alloy billet was prepared by SIMA （strain induction melt activation）. Billet dimension, heating temperature and heating time as well as extruded rate were determined in process of preparation of billet, re-melting and isothermal extrusion, and the mould for isothermal extrusion forming was designed. The average tensile strength and elongation of semi-solid isothermal-extruded magnesium alloy bullet supporter are 330 MPa and 7%, respectively, after solid solution and aging treatment, which are near to those of forging supporter.关键词：Semi-solid Forming;Isothermal Extrusion Casting;Thixo-forming;Magnesium Alloy
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发布时间：2023-12-18 - 摘要：Aiming at pin-hole defects in aluminum alloy cylinder head, which results in the waste rate over 30%, QC team was organized to eliminate the defects. The reasons from operator, machine, materials, rule and procedure were probed by three PDCA （plan, do, check, analysis） procedures. The results reveal that the pin-hole defects are resulted from inadequate refinery, higher pouring temperature, higher mould pre-heated temperature and mould structure. The pin-hole defects can be effectively eliminated by modifying mould structure and adding a core-mould for runner, decreasing waste rate to 1.36%.关键词：QC Management;Aluminum Alloy Cylinder Head;Pin-hole;Waste Rate
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发布时间：2023-12-18 - 摘要：Microstructure and mechanical properties of die casting Mg-8Zn-3.2Al-0.3Mn-0.7Si-0.06AlP alloy chain saw guide-plate cover in die castings were expounded. The results show that compared with those in gravity casting, the microstructure of the cover in die casting is evidently refined, and tensile strength and elongation is greatly improved. The microstructure of the cover with the improvement of mechanical properties can be greatly refined with AlP modifier addition. The rupture mechanism of the vover both in gravity casting and in die casting is characterized by mixed crack. In addition, the element Si exists as Mg2Si phase in gravity casting while it exists as Mg2Si phase and α-Mg solid solution in die casting.关键词：Magnesium Alloy;Die Casting;Chain Saw;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Design of gating system and mould for aluminum alloy cam cover of automobile engine was described. The processing parameters are as follows: slow injection velocity of 0.5 m/s, fast injection velocity of 4.55.0 m/s, holding pressure for 10 s, injection temperature at about 650 ℃ and pre-heated temperature of mould of 180250 ℃ as well as weight of injected liquid aluminum alloy of 4.5 kg. Aiming at gas hole existed in thick-large location of the casting, improvement of die casting process was performed. Meanwhile, the Anycasting software was employed to simulate filling process in improved die casting design, which is well in agreement with practical production. The cam cover meet the technical requirements and the qualified rate reachs 98%.关键词：Aluminum Alloy Cam Cover;Gating System Design;Processing Parameters;Gas Hole
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发布时间：2023-12-18 - 摘要：Aiming at the problems that utilization of high precision NC machine does not guaranted the manufacturing precision of casting mould, a data-based method to control manufacturing precision of casting pattern was proposed by analyzing the practical manufacturing status based on the fuzzy cluster method. The structural design, manufacturing design, working operation and equipment control in the method were taken as key points to realize the goal of pattern data-based precision to maximally approach the precision of the NC machine, finally, realizing the effective control to manufacturing precision of casting mould. The practical production confirms that strengthening data-based control can effectively improve the manufacturing precision of casting mould and provide a reference to quality control and management of the casting mould enterprises.关键词：Data;Mould Presicion;Foundry Tool;NC Machining;Quality Control
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发布时间：2023-12-18 - 摘要：The origination of some defects in investment casting stainless steel parts was analyzed including pockmark, black point, indentation, shrinkage depression. The results show that pockmark defects are resulted from the non-quality of shell-mold materials for face layer,and black point is resulted from the existence of non-metal inclusion in liquid steel.Indentation is attributed to the deterioation of properties of Zr sand at high temperature due to the existence of trace Mg,Ca element,which leads to the expansion of shell mold.Shrinkage porosity is closely related to the high pouring temperature. Based on above analysis, some key factors of quality control in investment casting were proposed,including the control of raw materials,brushing, dewaxing,melting and pouring,and so on.关键词：Investment Casting;Casting Defects;Quality Control
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发布时间：2023-12-18 - 摘要：It is very important to increase first-qualified rate of investment castings by strictly running processing principle and operation guide annual. Meanwhile, it is helpful for quality control by controlling key points in investment casting. Some experiences in sol silicate investment castings were described to improve quality and efficiency.关键词：Wax Pattern;Sol Silicate;Shell-making;Investment Casting
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发布时间：2023-12-18 -
- 摘要：An mathematical model for nozzle with three ports in continuous casting thin slab was established by coupling thermo-flow method based on mass equation, movement equation and energy equation of liquid steel in mould to simulate velocity field and temperature field in liquid steel. The main features of flow field and temperature field in nozzle with three ports during continuous casting were described to analyze effects on quality of billet. Meanwhile, the effects of immersing depth of nozzle and casting speed on the meniscus shape of liquid steel were understood to optimize flow field and pouring parameters of liquid steel in mould.关键词：Thin Slab;Nozzle with Three Ports;Thermo-flow Coupling
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发布时间：2023-12-18 - 摘要：Effects of Al content on microstructure and properties of carbon nanotubes/magnesium matrix alloy composites were investigated. The results show that the composites with fine grain exhibits desirable tensile strength, hardness and plasticity with 8% Al content. Coarse Mg17Al12 phase uniformly distributed along grain boundary is generated in the composites, resulting in the decrease of tensile strength and elongation with the increase of Al content.关键词：Magnesium Alloy;Composites;Carbon Nanotubes;Mechanical Properties;Microstructure
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发布时间：2023-12-18 - 摘要：Strawberry-like TiO2/Cu composite particles were prepared by hydrolysis of Ti（OBu）4 in acidic-abundant aqueous solution and reflux in the presence of micron size Cu powders. The processing parameters were optimized based on orthogonal design. The characteristics of the TiO2/Cu composite particles were observed by FE-SEM （field emitting -scanning electron microscope）, XRD（X-ray diffraction）, XPS（X-rat probe spectrum）, TG-DTA. The prepared TiO2/Cu composite particles exhibit strawberry-like structure, in which TiO2 particle with about 100nm in size is covered on Cu powder by FE-SEM observation. XRD analysis shows that TiO2 particle exhibits amorphous phase. There exist Cu2+, Ti4+, Sn2+ on surface of composite particles by XPS analysis. The oxidized temperature of composite particles is increased by 200 ℃ compared with that of Cu powder, showing different oxidization process.关键词：Micron Cu Powder;TiO2;Oxidization Resistance;Composite Particles
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发布时间：2023-12-18 - 摘要：Al-Si alloy high-voltage switch exhibits different types, low production and high quality, so it is difficult to meet the quality requirements by conventional casting method. The tilted pouring of no-bake resin sand mould for Al-Si alloy high-voltage switch was successfully performed by using self-designed tilted pouring equipment, which can decrease the production period and cost of mould and improve the mechanical properties and quality of the Al-Si alloy high-voltage switch.关键词：Al-Si Alloy;No-bake Resin Sand;Casting Mould;Titled Pouring
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发布时间：2023-12-18 - 摘要：Effects of MM on microstructure and mechanical properties of ZM5 magnesium alloy were investigated. The results indicate that microstructure of ZM5 magnesium alloy was evidently refined with MM addition. Meanwhile, tensile strength and elongation of ZM5 magnesium alloy can be improved, and they reaches 182 MPa and 4.54%,respectively, with 0.75%MM addition. After solid solution treatment for 25 hours, the tensile strength and elongation of the alloy with 0.75% RE addition can be reached up to 250 MPa and 8.05%, respectively, which is attributed to the creation of Al11Ce3 phase in the alloy enhancing grain boundary.关键词：ZM5 Magnesium Alloy;MM;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Effects of Ti, Zr and cerium-rich mixtures of rare earth on as-cast microstructure and properties of 5182 based alloys containing 0.03% Ti have been investigated by OM（optical microscope）, SEM （scanning electron microscope） and X-ray. The results show that the refining effects of Zr on 5182 aluminum alloy are superior to those of Re, however, the refining effects of Re on secondary dendrite in 5182 alloy are superior to those of Zr. The alloy with higher hardness and finer grain size can be observed with 0.20%Zr and 0.20% RE mixtures modification. The morphology which is obviously spheroidized and distribution of precipitates can be changed in the alloy with Ti and RE mixtures. Regular block precipitates containing Al, Ti, Zr are precipitated to be used as nuclei in Zr refined alloy, and the regular block phase containing Al, Ti and RE appeared in the RE refines alloy.关键词：5182 Aluminum Alloy;Grain Refinement;Secondary Dendrite;Precipitates
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发布时间：2023-12-18 - 摘要：Mg-3Zn magnesium alloys with 1.5%, 3.0% and 6.0% Y addition were prepared in crucible furnace with 7.5 kW. Effects of Y addition on microstructure and properties of Mg-3Zn alloy have been described. With increasing in Y addition, the secondary phase in the alloy is transformed from I phase +W phase into W phase +H phase, and the microstructure of the alloy gradually becomes coarse, in which the structure morphology is changed from needle-like into network structure. Meanwhile, with the increase of Y addition, the tensile strength, hardness, impact toughness are increased with the decrease of plasticity, however, with Y addition more than 6%, impacting toughness of the alloy is slightly declined.关键词：Mg-Zn-Y Alloy;Magnesium Alloy;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The wettability of Sn-2.5Ag-0.7Cu-xRE lead-free solder alloy on the 1206 component and Cu substrate was examined with the water-soluble flux by means of the wetting balance method. The results indicate that the highest wetting force and the biggest spreading area as well as the smallest wetting angle can be obtained with adding 0.1%RE in the Sn-2.5Ag-0.7Cu solder alloy, exhibiting desirable wetting properties, which can fully meet the wettability requirement of surface mount component due to its wetting force superior to that of commercial Sn3.8Ag0.7Cu solder alloy.关键词：Sn-2.5Ag-0.7Cu-xRE Lead-free Solder Alloy;Wetting Force;Spreading Area;Wetting Angle
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发布时间：2023-12-18 -
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