最新刊期
卷 ， 期 7 ， 2006
- 摘要：Effects of trace Er addition on the mechanical properties, microstructure, age-hardening characteristics and recrystallization behavior of the high strength Al-6Zn-2Mg alloy have been investigated by tensile property measurement, optical microscope （OM）, X-ray diffraction analysis （XRD）, scanning electron microscope （SEM）, transmission electron microscope （TEM） and energy spectrum analysis （EDS）. The results show that Er can greatly refine the grain size of the alloy, which is attributed to primary Al3Er as heterogeneous substrate to sharply improve nuclei rate. Tensile strength of the alloy has been significantly improved with Er addition as a result of fine grain strengthening and precipitated strengthening. Meanwhile, Er addition can improve age-hardening effects by accelerating ageing process of the alloy. In addition, Er can inhibit the recrystallization of the alloy and raise the recrystallized temperature, resulting from the pinning effects of the secondary fine Al3Er phase on dislocation and sub-boundary.关键词：Re Er;Al-Zn-Mg Alloy;Al3Er;Microstructure;Mechanical Properties;Recrystallization
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发布时间：2023-12-18 - 摘要：Effects of vacuum smelting-casting on the composition, microstructure and properties of the Cu-Cr-Zr-Mg alloy have been investigated to optimize the vacuum smelting-casting process, such as processing parameters, pre-treatment of cast mould. The results indicate that smelting temperature for the alloy should be controlled below 1 480 ℃, or else the alloy melt would react with the crucible matrix to result in the introduction of elements in crucible into the alloy. The burning-loss rate of elements in the alloy can be greatly decreased and the alloy composition can be accurately controlled by the vacuum smelting process. In addition, if pouring temperature is higher than 1 400 ℃, some defects, such as density-reduction, gas hole increase, coarse grain, segregation of the dendrite, deep porosity hole, are easily formed in the alloys.关键词：Cu-Cr-Zr-Mg Alloy;Cu Alloy;Vacuum Smelting-casting
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发布时间：2023-12-18 - 摘要：A new welding method of bi-friction stirring welding has been proposed. Microstructure and hardness of 6K32-T4 aluminum alloy joint in friction stirring welding （FSW） and in bi-friction stirring welding （Bi-FSW） have been compared, meanwhile the joint in Bi-FSW has been observed by XRD. The results show that microstructure distribution of the joint in Bi-FSW is identified with that of in FSW. However, the hardness in Bi-FSW is slightly lower than that in FSW, in which the declined area of the hardness in bi-FSW is larger than that of in FSW. Change of the phase constituent of the joint after bi-FSW is not observed. Using bi-FSW instead of FSW is beneficial to improving the welding efficiency and to eliminating tunnel-like joint defects due to higher linear energy, improving properties of the joint.关键词：Bi-friction Stirring Welding;Friction Stirring Welding;Structure
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发布时间：2023-12-18 - 摘要：Electrochemical parameters of the high Al-Zn base alloy containing 30%50% Al and 1.0%2.5% Cu, such as the Tafel parameters, resistance of linearization polarization （Rp） and corrosion potential （Ek）, have been measured by electrochemical measuring system in 3.5% NaCl solution. Corrosion morphology observation by the 3D video frequency microscope （HI-SCOPE Advanced KH-3000） was conducted also. The results show that the corrosion resistance of the alloy can be declined with increasing Al content and decreasing Cu content. The optimum corrosion resistance of the alloy can be observed with 30% Al content and 2.5% Cu content.关键词：Zn-Al Alloy;Electrochemical Parameters;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：The density, Vickers hardness, compressive strength, elastic modulus and bending strength of the Ti-Mo alloy were examined by adding Mo into pure Ti to prepare the binary alloy. Experimental results show that the alloy is characterized by equiaxed α+β phase. The Vickers hardness, compressive strength, compressive rate, elastic modulus and bending strength of the dental Ti-Mo alloy is 451, 1 636 MPa, 22.5%,29.8 GPa and 1 432 MPa, respectively, exhibiting excellent plasticity and mechanical properties. Ti-Mo alloy is used to dental industry, showing competitive prospect.关键词：Ti-Mo alloy;Vickers Hardness;Compressive Strength;Elastic Modulus;Bending Strength
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发布时间：2023-12-18 -
- 摘要：A solidification software suitable for complex process in low pressure casting has been developed based on the FDM through production of aluminum alloy automobile wheel, in which complicated conditions of boundary heat exchange in low pressure casting was considered, where different heat exchange modes were treated for various boundary elements. Different time-stages are adopted to accelerate calculated speed in processing simulation, meanwhile, the corresponding solved method was given for treating multi-wind channels in mould structure. The simulated results are well in agreement with practical ones.关键词：Low Pressure Casting;Solidification Simulation;Wind Channel;FDM
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发布时间：2023-12-18 - 摘要：Cooling-deformation and residual stress distribution in a diesel cylinder block castings can be observed by simulating temperature field and stress field during solidification process under three shake-out conditions with different temperatures based on FDM integrated system, and the three processing sketches are evaluated. The results show that the deformation of the castings is decreased with decreasing in shake-out temperature. Meanwhile, although shake-out temperature slightly affected the residual stress, it greatly affected the variation tendency of the stress value during solidification processing, where the lower the shake-out temperature is, the higher the stress during shake-out is.关键词：Diesel Engine Cylinder Block Castings;Numerical Simulation;Thermal Stress;Shake-out Condition
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发布时间：2023-12-18 - 摘要：Design of housing castings in low pressure casting based on CAD/CAE was introduced, in which 3D CAD mould design of the housing castings based on Pro/E and CAE simulation based on Any-casting software were described. Casting processing design can be visually conducted by means of CAD, and possible defect position can be predicted by CAE simulation to optimize mould structure and to improve casting quality.关键词：Housing;CAD/CAE;Low Pressure Casting
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发布时间：2023-12-18 - 摘要：Computer simulation was employed to optimize filling system to predict filling process and prevent the defects for Al alloy automotive parts in semi-solid die casting. By comparing formed appearance of parts in experiments and that in simulation, and observing the relationship between internal defects inspected by X-ray and flow field obtained in simulation, it is indicated that the calculated results are well in agreement with experimental ones. The computer simulation can accurately predict the possible casting defects during filling process to propose improved measures. The realization of numerical visualization for filling process of high speed during semi-solid die casting process can play an important role in optimizing technology plan and process.关键词：Computer Simulation;Semi-Solid Process;Al Alloy
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发布时间：2023-12-18 - 摘要：It is a developing tendency of MMCs （metal matrix composites ） to develop the MMNCs （metal matrix nano-composites）with high strength and excellent toughness. However, it has difficulty in preparing nano-particle reinforced bulk metal matrix composites by either liquid casting or solid sintering technologies. The technological theory, structure and properties of bulk MMNCs were expounded , and its development and future tendency were described also.关键词：Nano-size Reinforced Particle;MMNCs;Preparation
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发布时间：2023-12-18 - 摘要：Progress in Mg-based bulk metallic glasses was surveyed from some viewpoints of developed history, preparation, properties and composites. The problems encountered in development of the Mg-based bulk metallic glasses and its prospects were reviewed. It was pointed out that the development and commercial application of Mg-based bulk metallic glass products should be exploded while the development of the new Mg-based bulk metallic glasses should be paid attention to.关键词：Bulk Metallic Glass;Magnesium Alloy;Research Progress
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发布时间：2023-12-18 - 摘要：Size and distribution of Si phase in semi-solid hypereutectic Al-20Si alloy prepared by novel sloping plate process were investigated. The results show that structure of Si phase can be greatly improved. The fine and distributed primary Si phase can be observed under ambient conditions with tilting angular of 45° and length of tilting plate of 300 mm at pouring temperature of 630 ℃.关键词：Novel Sloping Plate;Semi-solid;Hypereutectic Al-Si Alloy;Primary Si
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发布时间：2023-12-18 - 摘要：Semi-solid casting-rolling for magnesium alloy has been conducted on a self-developed semi-solid casting-roller. The results show that the casting-rolling has greatly affected the microstructure of the semi-solid magnesium alloy. Primary phase in the semi-solid magnesium alloy is converted into spheroidized structure from irregular dendrite structure after casting-rolling. The spheroidized role of casting-rolling process is possible attributed to eliminating sharp angle by friction and flow between solid state and liquid state or coalescence of rotation and collapse of solid particle. In addition, microstructures of the semi-solid casting-rolling exhibits different characteristics at different processing conditions in surface and heart. The microstructure of thick plate is characterized by chilling fine equiaxed area on surface and semi-solid structure in heart while for thin plate, it is characterized by uniformly distributed structure.关键词：Casting-rolling;Semi-solid;Magnesium Alloy;Microstructure
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发布时间：2023-12-18 -
- 摘要：45 steel valve body in extruded casting was adopted in designing combined mould, in which core and punch adopts H13 tool steel, and sleeve and poisoned structure uses 45# steel or 40Cr steel. And special extruded machine with maximum extruded force of 1 500 kN and closed forces of 2 000 kN is used with punch velocity of 0.300.35 m/s. Drawing-mould declination is 2°,2°and 0.5°for up-punch, down-punch and side-punch, respectively. And the down-punch directly pushes the castings for pushing ways, where fit clearance between punch and the mould is 0.160.2 mm. The position of the die subjected to higher thermal stress has been cooled by tube-cooling combining with inserted-pipe cooling. Four overflow slots on cross-position of parting surface have been set to ensure the accuracy of the casting in height direction. To improve fusion-resistant ability of the die, the coating with thickness of 0.2 0.5 mm using self-developed siliceous earth coating is conducted.关键词：45 Steel;Extruded Casting;Design;Die Design;Valve Body
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发布时间：2023-12-18 - 摘要：Effects of processing parameters, including the pouring temperature, the die temperature, the ingate velocity, on tensile strength and grain size of die casting Mg alloy AZ91 HP have been investigated. The results show that with the increase of the pouring temperature and ingate filling velocity, the tensile strength is increased firstly and then decreased, while grain size is decreased firstly and then increased. However, with increasing in die temperature, tensile strength of the castings is improved and grain size is decreased. The tensile strength of 224.2 MPa and density of 1.77 g/cm3 of the samples with grain size of 14.4 μm can be observed at the pouring temperature of 680 ℃ and die temperature of 215 ℃ and ingate velocity of 70 m/s. Finally, an empiric formula between the grain size and tensile strength is established through linear regression.关键词：Die Casting;Magnesium Alloy;Processing Parameters;Grain Size
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发布时间：2023-12-18 - 摘要：It is one of the difficulties in the die-casting design for the design of the lateral core-pulling with long distance core-pulling and great closed forces, so the secondary core-pulling mechanism with angle pin, rack and gear has been used to solve the problems. It uses angle pin with high rigidity to pull core firstly, and when the mould is opened to a certain distance, the rack fixed on the fixed die begins to mesh with the gear, and the gear drives the sliding block with rack to finish the core pulling. The mould structure has been designed, and the working principle has been discussed. The technical parameters as well as practical problems in the mould have been given.关键词：Die-casting Die;Angle Pin;Rack;Gear;Core Pulling
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发布时间：2023-12-18 - 摘要：The characteristics of four kinds of popular technologies for shell-making in investment industry at home were compared. It was found that from the viewpoint of casting quality, the best is sol silica shell mold （middle temperature wax）, and then compound shell mold as well as sol silica shell mold （low temperature wax）, and then sodium silicate shell mold, while from the viewpoint of cost of shell making, the lowest is sodium silicate shell mold, and the highest is sol silica shell mold （middle temperature wax）. The improved measures for the four methods were proposed, respectively.关键词：Sol Silicate;Sodium Silicate;Shell Making;Low Temperature Wax;Middle Temperature Wax;Investment Casting
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发布时间：2023-12-18 - 摘要：Surface composites cast iron can be prepared through infiltrating liquid iron into coating based on brushing slurry on EPS foamed model in evaporative pattern casting （EPC）. The slurry is composed of SiC powder, EPS bead, Cr-Fe powder and auxiliary infiltration agent as well as binder, etc. The effects of SiC and EPS bead on the surface quality, microstructure of infiltrated layer and wear resistance of the surface composites cast iron were observed. It is found that surface quality of the surface composites cast iron is excellent with SiC particle size of 2 μm and volume fraction of 50%, where its weight-loss is 37% of that of cast iron matrix, showing the highest wear resistance.关键词：EPC;Cast Iron;Wear Resistance;Slurry
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发布时间：2023-12-18 - 摘要：The key points of designing the lost foam mould for non-machining cross valve were described based on its structure characteristics. The pattern could be molded in whole without gluing on the device of three core-pulling with guide bars. Meanwhile, improved measures were conducted to further optimize the structure of the lost foam mould. The practical application shows that the mould can meet the requirements of production-volume.关键词：Lost Foam Mould;Core-Pulling Mechanism;Cross Valve
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发布时间：2023-12-18 - 摘要：Aiming at crack accident of roller-body of high Cr cast steel centrifugal compound roller for continuous caster, the origination of the crack was analyzed by investigating characteristics and fracture morphology of the compound roller, by analyzing microstructure of outer and heart in fracture, and by measuring residual austenite content in metastability phase in outer and calculating thermal stress during operation process. Large temperature-difference between outer and heart of the roller results in the thermal stress crack due to inadequate preheated time for roller during rolling process. The countermeasures are given.关键词：High Cr Cast Steel Centrifugal Roller;Crack;Thermal Stress
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发布时间：2023-12-18 - 摘要：Microstructure and mechanical properties of Zn-50Al （ZA50） alloy in permanent mold casting were investigated. The results show that as-cast microstructure of the ZA50 alloy with tensile strength of 477 MPa in permanent mold casting is composed of α phase, （α+η）eutectoid structure and intermetallic compound, while microstructure of the alloy after aged at 200 ℃ is composed of α phase, particle （α+η）eutectoid structure and intermetallic compound, and its tensile strength reaches 354 MPa. The strength and ductility of ZA50 alloy are higher than those of ZA27 alloy. The morphology of formed intermetallic compound in ZA50 alloy was analyzed also.关键词：Permanent Mold Casting;ZA50 Alloy;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：Effects of adding ways and addition of Al-5Ti-B master alloy on grain size of 3102 aluminum foils in casting-rolling process are investigated. The results show that the 3102 aluminum alloy billets with uniformly distributed grain below 0.1mm in size can be prepared by adding Ti content of 0.03% 0.06% , where silk-like Ti addition is over 0.01%, the other is bulky. The operation and optimized processing parameters of controlling coarse grain in 3102 aluminum billet are approached.关键词：Aluminum;Casting-rolling;Grain;Refiner;Al-Ti-B Master Alloy
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发布时间：2023-12-18 - 摘要：AZ80 magnesium alloy rod was squeezed with reclaimed chip by means of hot press-hot extruded deformation,where chipping temperature is 330 ℃ ,die temperature is 350 ℃ and pressure is about 200 MPa during hot pressing while squeezing rate is 25 and squeezing velocity is 20 mm/s during squeezing castings.The tensile strength,yield strength and elongation of the reclaimed rod treated at 200 ℃ for 8 hours are 310 MPa ,230 MPa and 7%,respectively.The microstructure and mechanical properties of hot extruded AZ80 magnesium alloy chip are approached.关键词：AZ80 Magnesium Alloy Chip;Hot Pressing;Hot Squeezing Casting;Heat Treatment
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发布时间：2023-12-18 - 摘要：TiO2 film is formed to clad the surface of the Cu powder by hydrolyzing sol-gel process for improving the oxidation resistance of copper powders. Effects of various water, acid and sol-gel quantity on cladding effects are investigated by measuring transmissivity rate away from 760 nm of the solution under the condition of eroding the samples in 5% H2SO4 solution for four hours. The results show that the transimissivity rate of the coat samples at 760 nm is more than 80% with 1 to 2 of Ti（OBu）4 and H2O, 0.32 mol/L of H+ content and 4%6% TiO2 sol, while that of initial samples is 15%.SEM, EDS, XPS and XRD are employed to characterize the coated samples. XPS analysis shows that the main elements in the surface of the coated copper podwders are Ti, Sn, C, O and Cu, in which Ti and Sn are in the state of Ti +4 and Sn +2 , respectively. The XRD analysis for coated copper powder and initial samples after 60 day in air indicates that the advents of Cu2O in surface of the initial samples are observed, while only Cu can be observed in the coated samples.关键词：Sol-gel Method;TiO2;Cu Powder;Oxidation Resistance
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发布时间：2023-12-18 - 摘要：Current-carrier friction-wear behavior and microstructure of Al2O3/Cu composites prepared by internal oxidation were investigated. The results show that nano-Al2O3 particle can be dispersively distributed into the Cu matrix. The wear resistance of the composites is greatly superior to that of the Cr-brass alloy in case of current carrier. The wear morphology is characterized by abrasive wear and adhesion wear with low current while it is characterized by adhesion with high current. Current has obviously affected on wear rate compared with loading.关键词：Internal Oxidation;Al2O3/ Cu Composites;Friction-wear Behavior
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发布时间：2023-12-18
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