最新刊期
卷 30 ， 期 2 ， 2010
-
- 摘要：Microstructure and size of 6061 aluminum alloy semi-solid billets prepared by near-liquidus semi-continuous casting, which was reheated at different heating temperature and holding time, were observed by the Nikon E600POL optical microscope and image analyzer to investigate the formation of liquid phase, microstructure evolution and grain growth during reheating process combining with differential thermal analysis （DTA）. The results reveal that microstructural evolution is controlled by reheating temperature and holding time. With increasing in heating temperature and extending in holding time, grain is grown spherically and gradually, furthermore, microstructural evolution is faster and faster with increasing in heating temperature, and grain is grown more and more spherically with extending in holding time. The 6061 aluminum alloy semi-solid billets with homogeneous and round as well as fine structure can be prepared by effectively controlling reheating temperature and holding time.关键词：Semi-solid;6061 Aluminum Alloy;Reheating;Microsctuctural Evolution;Phase Transformation
- 2
- |
- 339
- |
- 12
发布时间：2023-12-18 - 摘要：Effects of deformation rate on recrystallization and properties of 7150 aluminum alloy were investigated by tensile testing, intergranular corrosion, exfoliation corrosion, electrochemical testing and optical microscope（OM） and SEM （scanning electron microscope）. The results indicate that the volume of recrystallization is increased with increasing in deformation rate. The highest mechanical properties can be observed with 75% deformation rate, and the lowest intergranular corrosion and exfoliation corrosion sensitivity are measured with 60% deformation rate, which is verified by electrochemical testing. The volume of recrystallization which increases with deformation rate increases is mainly responsible for weakening the resistance of local corrosion. Taking mechanical and local corrosion properties into account, the optimized deformation rate is 75%.关键词：7150 Aluminum Alloy;Deformation Rate;Properties;Recrystallization
- 2
- |
- 573
- |
- 11
发布时间：2023-12-18 - 摘要：Al-35La alloy was prepared by different casting molds, such as permanent mold, graphite mold and sand mold with vacuum melting furnace, and its microstructure and mechanical properties were examined. The results show that microstructure of the Al-35La alloys prepared by different casting molds are composed of periodic two-phase dendrites. The hardness and relative compressibilities of the alloy prepared by different casting mold are approximately the same. Alloy exhibits a higher compression strength with 10% relative compressibility , which is attributed to discontinuous distribution of Al11La3 phase in the alloy refining grain size. Furthermore, the forming mechanism of the Al11La3 phase was described.关键词：Al-35La Alloy;As-cast Structure;Periodic Two-phase Dendrite;Mechanical Properties
- 2
- |
- 80
- |
- 1
发布时间：2023-12-18 -
-
-
-
-
- 摘要：Effects of Ta, Zr on properties and microstructure of solid solution Ti alloy were investigated by analyzing Ti-ANb-Ta, Ti-ANb-BTa-Zr series alloys. Solid solution Ti-ANb-Ta, Ti-ANb-BTa-Zr series alloys exhibit lower elastic modulus in which the lowest value is 58 GPa and excellent plastic performance in which maximum value of elongation and contraction of area reach 32% and 80%, respectively. With increasing in Ta and Zr contents, tensile strength of the alloys is increased in range of 500700 MPa. Microstructure of the solid solution alloy is composed of residual β phase and acicular martensite α″, in which with increasing in Ta and Zr, residual β phase is increased with the decrease of acicular martensite α″.关键词：Ti Alloy;Elastic Modulus;Microstructure;Solid Solution;Mechanical Properties
- 2
- |
- 213
- |
- 2
发布时间：2023-12-18 - 摘要：Effects of the melt thermal treatment with composition compensation on morphology of primary Si in hypereutectic Al-20Si alloy were investigated. The results show that the technology can refine grain size of primary Si to approximately 36 μm within 100 min, exhibiting an obvious modification effect on the primary Si and a long duration time. So the melt thermal treatment with composition compensation is a simply and practical technology for modifying the primary Si in the Al-20Si alloy without modifier addition.关键词：Al-20Si Alloy;Composition Compensation;Melt Thermal Treatment
- 2
- |
- 144
- |
- 4
发布时间：2023-12-18 - 摘要：Electro-slag casting is a technology combining refinement with forming, which exhibits a multi-objective problem due to not only utilizing the advantages of purifying materials but also considering product efficiency and cost. The purification coefficient of consumable electrode end, melting ratio of consumable electrode and effective power factor are presented to be taken as the optimized target. A multi-objective optimized system of processing parameters for electroslag casting was established on the Matlab platform based on artificial neural network and genetic algorithm theory by designing remelting current, depth of slag pool and flow rate of cooling water as variables, showing a positive reference for practical production.关键词：Artificial Neural Network;Genetic Algorithm;Optimization;Electroslag Casting
- 2
- |
- 120
- |
- 3
发布时间：2023-12-18 - 摘要：Filling and solidification of large thin-walled A356 aluminum alloy components were simulated by the FEM （finite element method） in condition of different pouring ways to predict the potential defect position occurred in the thin-walled components, and the merits and demerits of different gating systems were comparatively analyzed. The results show that shower gating system is favorable for the filling process of large thin-walled aluminum alloy components, in which entrapped-gas and shrinkage porosity （hole） are decreased as a result of smooth filling and sequential solidification. The qualified front cover plate for vehicle with 1272 mm in length and 506 mm in width and 4.7 mm in thickness can be successfully produced by employing the shower gating system.关键词：A356 Aluminum Alloy;Numerical Simulation;Thin-walled Components;Gating System
- 2
- |
- 277
- |
- 7
发布时间：2023-12-18 - 摘要：Effects of central angle, frictional coefficient on the forming of ECAP were analyzed by simulating ECAP process of 6061 aluminum alloy at room temperature with the help of FEM （finite element method）. The results reveal that with decreasing in central angle, equivalent strain of the samples is increased with more homogeneous distribution, however, pressing load is increased. Friction coefficient is closely related to the forming load. The samples exhibit heterogeneous deformation after one pressing.关键词：6061 Aluminum Alloy;ECAP;FEM;Central Angle;Frictional Coefficient;Grains
- 2
- |
- 341
- |
- 1
发布时间：2023-12-18 - 摘要：Four kinds of manufacturing methods to prepare γ-TiAl alloy based sheet were described. The special rolling method exhibited relative mature with a narrow processing window. Low impurities can be observed in the sheet by foil metallurgy and EB-PVD methods. Microstructure shows heterogeneous in the sheet prepared by rolling-casting method. Effects of alloying elements and heat treatment on microstructure of the γ-TiAl alloy based sheet were expounded, and developing future of the methods was predicted.关键词：TiAl Based Alloy;Sheet;Microstructure;Mechanical Properties
- 2
- |
- 269
- |
- 1
发布时间：2023-12-18 - 摘要：Mechanical behavior of AZ91D-3Ca magnesium alloy prepared by pulsed magnetic field during semi-solid compression was investigated with help of the Gleeble-1500 hot simulator to understand effects of deformation temperature and strain rate on semi-solid compressive stress. The results reveal that, compared with that prepared by conventional casting, compressive behavior of magnesium alloy prepared by pulsed magnetic field is similar during compressive deformation at 400℃, however, lower deformation resistance can be observed at semi-solid temperature （510℃）. When other conditions keep the same, with the increase of deformation temperature or the decrease of strain rate, deformation resistance of the alloy is decreased. Deformation resistance makes in range of 0.381.6 MPa with 0.0050.5 s-1 and 510520 ℃ deformation temperature.关键词：Pulsed Magnetic Field;AZ91D-3Ca Magnesium Alloy;Compressive Deformation
- 2
- |
- 151
- |
- 1
发布时间：2023-12-18 - 摘要：Ignition-proof of high bauxite coating for permanent mold casting magnesium alloy was investigated. The results reveal that chemical reaction between alloy melt with high bauxite can be easily conducted on the runner of permanent mold, leading to the failure of the coating. Mg2Al3 and Mg2Si phase can be observed in the reaction products. Reaction between the alloy melt and high bauxite can be weakened by adding inhibitor, and the service life of the coating is increased with increasing in inhibitor addition. The desirable inhibitor addition is approximately 6%.关键词：Magnesium Alloy;High Bauxite Coating;Ignition-proof;Inhibitor
- 2
- |
- 200
- |
- 3
发布时间：2023-12-18 - 摘要：Structure characteristics and forming process of drive end cover were analyzed. Combining with manufacturing process of mould, multi-step parting face was determined as the main parting face of the mould, and angle pin location was adopted to make mould structure compact. Hydraulic drawing-core mechanism was adopted for two-side of inner-sinking in the die casting die, and pre-resetting mechanism was set to avoid the interference of core slide with ejector pin. Eccentric slitting runner was designed in gating system, in which runner and ingate were set on left and right slide,respectively, taking the desirable filling and exhaust during die casting process, effectively improving the quality and qualified rate of the drive end cover.关键词：Drive End Cover;Die Casting Die;Multi-step Parting Face;Hydraulic Drawing-core;Slitting Runner
- 2
- |
- 182
- |
- 5
发布时间：2023-12-18 - 摘要：Good lubrication on surface of mould is a key factor ensuring die casting and improving product quality. We have developed an inner-spraying-coating technology to resolve partial undesirable lubrication in the mould. The practical production verifies that the soldering and tearing defects in the product can be greatly reduced by employing the inner-spraying-coating method, and the defect rate is less than 0.9%. Meanwhile, stability of mass-production and efficiency are improved.关键词：Die Casting;Spraying-coating;Die Casting Die;Soldering
- 2
- |
- 159
- |
- 2
发布时间：2023-12-18 - 摘要：In order to resolve the problems in over-long motion of loose core and difficulty to demould in gracile conical tube castings, a die casting die with a special mechanism of loose core-ejecting castings for long conical sleeve was designed. Processing characteristics of the sleeve was analyzed, and structure design and operation procedure of die casting die were described. A mechanism of angle pin and floating slider is adopted in the die, where the slider for loose core could not only move along direction of loose core, but also float along direction of ejecting casting. Firstly, the mechanism of angle pin and floating slider performs a short distance loose core, and then the ejector pins drive the slider and core along direction of ejecting casting, pushing the castings off the ejector die, which can greatly reduce the open-mould distance and decrease the equipment cost, improving product efficiency. The die exhibits compact in structure and reliable in operation. There exists no mark brought by ejecting casting, showing high product quality.关键词：Die Casting Die;Mechanism of Angle Pin and Floating Slider;Conical Tube Castings;Core-Pulling Mechanism
- 2
- |
- 56
- |
- 0
发布时间：2023-12-18 - 摘要：Effects of pressurization starting time and reduction on microstructure of hypereutectic B390 aluminum alloy cylinder body for automotive were investigated during partial pressurization process by squeezing casting. The results reveal that through employing partial pressurization at hot spot of thick wall position of cylinder body, casting defects, such as shrinkage porosity （hole）, easily encountered in thick wall position of the cylinder body can be eliminated with pressurization starting time of 10 s and reduction of 20 mm. Average tensile strength, hardness （HB） and elongation of the cylinder body after T6 heat treatment reach up to 305MPa, 137 and 4.8%, respectively. And the samples picked randomly successfully pass the 1.38MPa halogen gas testing with no leakage.关键词：Squeezing Casting;Pressurization Casting;Cylinder Body;Heat Treatment
- 2
- |
- 159
- |
- 2
发布时间：2023-12-18 -
-
- 摘要：Effects of different factors on grain rate of turbine blade with equaixed grain were analyzed, including mold shell temperature, pouring temperature, particle size and content of refiner, solidification ways, compound ways, shell mold material and thickness as well as mold-making. Combining production product, main control measures and processing parameters were presented, which could provide a reference to further optimize process and improve quality of components.关键词：Investment Casting;Turbine Blade;Grain Rate
- 2
- |
- 446
- |
- 6
发布时间：2023-12-18 - 摘要：Sol-gel forming is a desirable technology for preparing ceramic mold with homogeneous composition and complex structure. Effects of different solid content, particle rate and additive on performance of ceramic core were investigated, and effects of pH value on fluidity of slurry were analyzed to decrease slurry viscosity and improve the solid content. Al2O3 ceramic slurry with 58% solid content and 0.086 Pa·s viscosity was successfully prepared. Green strength of formed billets can reach up to 34MPa, fully meeting the requirements of next production.关键词：Sol-gel;Solid Content;Viscosity;Aadditive;Ceramic Core
- 2
- |
- 287
- |
- 1
发布时间：2023-12-18 - 摘要：A mathematical model on the electromagnetic continuous casting magnesium alloy billets was established to predict the temperature distribution in the billet and dummy block using VC++6.0 and finite differential method（FDM）. Induction heating distributions at horizontal and vertical directions along mould at varied conditions were presented by measuring induction heating and its distribution in electromagnetic continuous casting billets based on temperature-increment method, and induction heating power was calculated, which was considered into the mathematical model for calculating temperature field. Boundary conditions of primary、secondary cooling zone and interfacial cooling between billet and dummy block were determined. The simulated results are well in agreement with the experimental ones, showing the availability of the model. Effects of different parameters on distribution of temperature field in billets were investigated to optimize the processing parameters.关键词：Magnesium Alloy;Electromagnetic Continuous Casting;Temperature Field;Numerical Simulation
- 2
- |
- 276
- |
- 2
发布时间：2023-12-18 - 摘要：The FEM model of the mould for 7050 aluminum semi-continuous casting round billets was built up by CFD software Fluent, and flow filed of the aluminum alloy melts sonicated in the mould was analyzed, focusing on effects of acoustic streaming on the flow field. The results reveal that large-scale Echart acoustic streaming was formed in the liquid phase zone, driven by the radiation force which was formed as a result of the acoustic pressure gradient resulting from the viscous attenuation. As the amplitude and the scale of the Eckart acoustic streaming were much smaller than those of the flow field in the mould, effects of acoustic streaming on the flow filed can be neglected. The vortices from the flow field in nozzle transfer the effective nuclei and equiaxed grains formed in the cavitation area to the other area of the liquid pool and brings the other melt to the cavitation area in turn, forcing the others to be equiaxed grains and effective nuclei, finally, the structures of the ingot are all equiaxed grains. Effects of acoustic streaming on enlarging the refinement area can be negligible in the semi-continuous casting experiment.关键词：Semi-continuous Casting;Mould;Ultrasonic;Flow Field;Radiation Force;Acoustic Streaming;Refinement Area
- 2
- |
- 266
- |
- 2
发布时间：2023-12-18 -
-
-
- 摘要：A new process of compound mold shell for lost foam casting was presented based on foam pattern, which utilized foaming confection to get high quality foam pattern prototypes, then prepared 23 layers compound ceramic shell of silica sol-sodium silicate on the surface of foam pattern, finally, prepared the backup layer of ceramic shell with no-bake sand. Dewaxing of ceramic mold shell was carried out in methylene chloride dissolvent at 200300℃ for 30 min, and then the ceramic mold shell was baked at 800 ℃ for 1 h. The results reveal that the shell-making process has the features of simply and short period as well as low cost. The prepared compound shell possesses clean surface and high strength. Meanwhile, ZL101 alloy castings with high quality were obtained with the compound shell.关键词：Foam Pattern;No-baked Sand;Back up;Compound Shell
- 2
- |
- 219
- |
- 2
发布时间：2023-12-18 -
- 摘要：Curing properties of magnesia hardener for phosphate binder were investigated by varying the magnesia addition. The results indicate that with increasing in magnesia addition, the stripping time and working time are reduced. The strength of the samples is firstly increased and then decreased with the increase of storage time, where the maximum value is observed at 1820 h. The low residual strength and gas evolution are independent of the magnesia addition.关键词：Phosphate;Hardener;Magnesia
- 2
- |
- 271
- |
- 2
发布时间：2023-12-18 - 摘要：Fully dense Nb/Nb5Si3 in-situ composites were successfully prepared by SPS smelting-casting, and phase constituent and microstructure of the composites were investigated by XRD （X-ray diffraction）, SEM （scanning electron microscope）, EPMA （electron probe micro-area analysis） and EDS（energy disperse spectroscopy）. The results indicate that microstructure of the Nb/Nb5Si3 in-situ composites prepared by SPS smelting-casting is composed of near-spherical primary Nb particle and （Nb+Nb5Si3） eutectoid, and with increasing in cooling rate, near-spherical primary Nb particle and （Nb+Nb5Si3） eutectoid are refined gradually. Prepared composites reach 99.69% theoretical density in density. Integration of in-situ synthesis with liquid forming can be realized in preparation of Nb/Nb5Si3 in-situ composites by SPS smelting-casting.关键词：Spark Plasma;Nb/Nb5Si3 in-situ Composites;SPS Smelting-casting
- 2
- |
- 118
- |
- 1
发布时间：2023-12-18 - 摘要：Nano-sized SiC particle reinforced AZ61 magnesium matrix composites SiCp/AZ61 was prepared by a self-developed high-energy ultrasonic device, and microstructure and damping behavior of the prepared composites were investigated by OM （optical microscope） and SEM （scanning electron microscope）. The results reveal that SiCp particles can be uniformly and dispersedly distributed in the magnesium alloy melt by high energy ultrasonic. The damping behavior of the composites is greatly superior to that of AZ61 matrix alloy at room temperature, which is attributed to G-L dislocation-pinning theory. Interface slipping at high temperature can be easily conducted due to SiCp increasing the quantities of grain-boundaries of matrix alloy, resulting in the significant improvement of damping behavior of the composites.关键词：Magnesium Matrix Nano-composites;High Energy Ultrasonic;Damping Behavior
- 2
- |
- 257
- |
- 2
发布时间：2023-12-18 - 摘要：Effects of graphite addition on frictional behavior of Al-9Gr matrix composites prepared by semi-solid mechanical-electromagnetic stirring method were investigated. The results indicate that wear mechanism of Al-9Gr composites with graphite addition is characterized by the plowing and delamination abrasion. The friction coefficient of the composites is increased with increasing in pressure and it is decreased with increasing in time, meanwhile, it is decreased with increasing in homogenization of graphite on wearing surface during friction process of Al-9Gr composites.关键词：Al-9Gr Composites;Friction;Friction Coefficient
- 2
- |
- 81
- |
- 1
发布时间：2023-12-18 - 摘要：Effects of rotating magnetic field on microstructure and crystallized temperature of Al-（45）Cu alloy were observed by rapidly setting molten Al-Cu alloy in rotating magnetic field. The results indicate that, in condition of rotating magnetic field, solidification structure in the alloy is converted from coarse dendrite in the alloy without rotating magnetic field into near equaixed grain with more homogeneous distribution, exhibiting obvious refining role, meanwhile, grain distance and crystallized grain region are greatly decreased. Mechanism of rotating magnetic field influencing solidification structure of Al-Cu alloy was described on the basis of theoretical mechanics and fluid mechanics.关键词：Rotating Magnetic Field;Al-Cu Alloy;Solidification Structure;Theoretical Mechanics;Fluid Mechanics
- 2
- |
- 226
- |
- 2
发布时间：2023-12-18 - 摘要：The microstructure and wear-resistant properties of TiN films which were deposited by multi-arc ion plating system on the surface of ZL109 aluminum alloy were investigated. The results reveal that the growth pattern of TiN films deposited on the ZL109 aluminum alloy exhibit planar growth mode at low temperature, which is converted into island mode with increasing in deposition temperature and in time. TiN films with 2 μm in thickness can be observed with deposited at 280 ℃ for 1 hours. After the TiN films deposited on the surface of ZL109 aluminum alloy, the wear-resistant properties are increased about four times, compared with those of the samples with deposited-free.关键词：Multi-arc Ion Plating;TiN Films;Growth Pattern;Wear Resistance
- 2
- |
- 222
- |
- 1
发布时间：2023-12-18 - 摘要：Effects of RE elements Y and Gd on microstructure and mechanical properties of ZA63 magnesium alloy were investigated by alloy preparation, microstructural analysis and tensile testing. The results reveal that with appropriate RE element Y and Gd addition, τ-phase in the ZA63 alloy is converted from semi-continuous network structure into needle-like or rod-like structure with more homogeneous distribution, in which Mg-Al-Zn-RE phase is formed as a result of some RE solution, and ε-phase is converted from island shape into fine particle. With increasing in RE addition, the tensile strength and elongation of the alloy after T6 treatment exhibit firstly increased and then decreased at room temperature, 150℃, and 175℃. Maximum value of tensile strength and elongation of the alloy at room temperature, 150℃, and 175℃ can be observed with 1.5% RE addition.关键词：ZA63 Alloy;Y;Gd;Microstructure;Mechanical Properties
- 2
- |
- 209
- |
- 2
发布时间：2023-12-18 - 摘要：Free-cutting mechanism of Pb in the copper alloy and progress in free-cutting copper alloy with lead-free were surveyed, focusing on the feasibility and existing problems in free-cutting copper alloy with Bi. Microstructure and cutting experiment of a self-developed free-cutting copper alloy containing Mg and Sb as wellas lead-free were analyzed by SEM and EDS as well as cutting testing. Developing future of free-cutting copper alloy with lead-free was expounded, and research in enlarging mixed-addition in substituting lead was enhanced.
- 2
- |
- 257
- |
- 6
发布时间：2023-12-18 - 摘要：It is important to rationally choose chemical composition in the bismuth brass by investigating effects of elements in environmentally-friendly bismuth brass on its cutting properties. The results reveal that with increasing in Cu content, the cutting properties of the alloy are declined gradually, while with increasing in Bi content, cutting properties are improved gradually. In addition, with increasing in RE content, its cutting properties are firstly decreased and then increased, where the cutting properties are the same with 0.03% RE addition and 0.09 RE addition.
- 2
- |
- 176
- |
- 1
发布时间：2023-12-18 - 摘要：The xugongning pieced ornament with snake shape was whole cast, in which the absence of welding and cast-in interface was observed, by detecting the castings, analyzing structure and tracing processing mark. Xugongning pieced ornament with snake shape was successfully replicated by simulating traditional investment casting, in which wax was made of rosin, beeswax, rapeseed oil, and shell mold was made of fine clay, plant ash, fine sand, fine pan ash, showing investment casting process existed in the Chinese bronze age.关键词：China;Early Stage;Investment Casting;Replication
- 2
- |
- 276
- |
- 1
发布时间：2023-12-18 -
-
-
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0