最新刊期
卷 ， 期 8 ， 2006
- 摘要：The distribution of La in aluminum alloy matrix and its effects on solute segregation during matrix solidification are investigated based on Al2O 3f /Al-Mg-La composites prepared by squeezing casting. The results show that enrichment of La on interface is favorable for improving the wettability of Al2O 3f particle in liquid aluminum alloy. However, the absence of RE-enriched on interface are observed. La has slightly affected on segregation of Mg in matrix alloy, and both Mg and La can enrich on interface with the same position distribution.关键词：La;Composites;Solute Segregation;Al2O 3f;Al-Mg Alloy
- 2
- |
- 92
- |
- 2
发布时间：2023-12-18 - 摘要：A high frequency amplitude-modulated magnetic field is realized by superposing a low frequency signal on the high frequency magnetic field. And the distribution of magnetic induction density, B, was measured by the small coils method. The results show that the higher B is observed in middle-bottom position, where that at the edge is higher than that of the center. The B can be increased with the increasing in amplitude-modulated value in the range of amplitude-modulated value of 0.57 V with amplitude-modulated signal frequency of 5 Hz. The B value of 0.029 T can be observed at the amplitude-modulated value of 7 V . The behavior of molten meniscus fluctuation in the magnetic field indicates that with the increase of magnetic induction density, the defined force is increased, which lessened the pressure between the molten and the crucible to result in the regular fluctuation of the meniscus.关键词：High Frequency Amplitude-modulated Magnetic Field;Magnetic Induction Density;Meniscus Fluctuation
- 2
- |
- 127
- |
- 6
发布时间：2023-12-18 - 摘要：Effects of Boron on fluidity of the Al-13Si- 0.3 Mg alloy are observed by pouring spiral sample, where the temperature correction method is used to correct the experimental results to decrease the effects of error of pouring temperature. The results reveal that the fluidity of the alloy can be greatly improved with the increase of B content. The solidified behavior is investigated by liquid quenching for the alloy in the middle stage of solidification. The fluidity of the Al-13Si-0.3Mg alloy is analyzed by observing the solidified microstructure and solidified behavior.关键词：Fluidity;Al-Si Alloy;Boron
- 2
- |
- 184
- |
- 3
发布时间：2023-12-18 - 摘要：The microstructure and properties of cemented carbide on the interface of high speed steel by thermal spraying-vacuum powder sintering are investigated. The interface characteristics and bonding strength between coating and high-speed steel substrate, micro-hardness at varied temperatures and wear resistance of high speed steel-cemented carbide composites are analyzed. The results indicate that the cemented carbide coating with 13 mm in thickness and 450 MPa in bonding strength and 85 HRA in micro-hardness can be prepared after thermal spraying by vacuum powder sintering at 1 200 ℃, exhibiting higher wear resistance.关键词：Cemented Carbide;High Speed Steel;Vacuum Powder Sintering;Thermal Spraying
- 2
- |
- 160
- |
- 3
发布时间：2023-12-18 - 摘要：A simulation software, HRSCAE, for temperature field in HRS directional solidification process is developed based on preparation process of turbine blade with columnar crystal. The effects of varied drawing velocity, heating and cooling rate on distribution of temperature field in turbine blade with columnar crystal and liquid-solid interface morphology are examined by orthogonal testing method. The results indicate that the drawing velocity is dominant in influencing casting quality. The drawing velocity is controlled to make the interface always be adjacent to the isothermal zone, which can keep the solid-liquid interface to be flat for a long time. It is more favorable for the growth of the columnar crystal with the solid-liquid interface more adjacent to the isothermal zone. The simulation provides some ways to exactly control parameters and to solve divergence problems in real production to produce the high quality columnar crystal with smooth surface.关键词：Columnar Crystal;Turbine Blade;HRS Directional Solidification;Interface Morphology;Simulation
- 2
- |
- 159
- |
- 1
发布时间：2023-12-18 - 摘要：A model for liquid-solid extruding process is established by introducing an artificial neural network into parameter sensitivity analysis during the liquid-solid extruding process. Sensitivity value at per sample point of the processing parameters can be obtained to quantitatively determine the sensitivity index under co-action of several uncertainty parameter conditions by mapping nonlinear network to resolve partial differential coefficient of output via input based on the model. The results show that the influencing orders on liquid-solid extruding process is infiltrating time, and then pouring temperature and mould temperature, and then infiltrating pressure, which are accordant with experimental ones.关键词：Liquid-solid Extruding Process;Neural Network;Sensitivity
- 2
- |
- 72
- |
- 2
发布时间：2023-12-18 - 摘要：The deformed behavior of high solid fraction semi-solid materials is paid attention to. The two-phase constitutive model is built up to describe the deformed behavior based on the continuum dielectric dynamics and coupled model. The parameters for constitutive model are determined based on isothermal compressive data of semi-solid Al-4Cu-Mg alloy, providing a reference for further investigation of semi-solid material production and numerical simulation as well as practical application.关键词：Semi-solid;High Solid Fraction;Two-phase Structural Model
- 2
- |
- 243
- |
- 4
发布时间：2023-12-18 - 摘要：The effects of interface structure on mechanical properties of the interface were examined by quantitatively determining interface structure of semi-solid steel-Al-Pb compound plate using Re-Al compound ratio on the interface. The nonlinear relationship between Re-Al compound ratio on the interface and interfacial shearing strength has been observed. When the Re-Al compound ratio on the interface is lower than 70%, the interfacial shearing strength can be gradually increased with increasing in Fe-Al compound ratio. When the ratio is higher than 70%, the interfacial shearing strength can be gradually decreased with the increase of the ratio. The maximum interfacial shearing strength of 70 MPa can be observed when the Fe-Al compound ratio on the interface is about 70%.关键词：Semi-solid Bonding;Fe-Al Compound Ratio;Mechanical Properties
- 2
- |
- 151
- |
- 1
发布时间：2023-12-18 - 摘要：Effects of twin-screw structure on the microstructure of semi-solid Mg alloy slurry have been investigated, meanwhile, comparison between effects of twin-screw and of single-screw has been conducted. Experimental results indicate that fine spheroidized structure with average diameter of 4060 μm in the slurry can be prepared by both combination twin-screw stirring and single screw thread twin-screw with high shearing rate, where the range of solid fraction can be controlled from 15% to 60%. However, compared with single screw thread twin-screw structure, the combined twin-screw structure can take more stirring effects due to the delivery, shearing, mixing mechanism, strengthening homogenization of the melt and shearing effects, thus the structure of semi-solid magnesium with finer and more round can be obtained. In contrast, because of the weak effects of mixture with low shearing rate, the solidified microstructure of the slurry prepared by single screw is strip shape or anomalous block with the primary grain size in the range of 6080 μm.关键词：Screw Structure;Semi-solid;Mg Alloy;Slurry
- 2
- |
- 74
- |
- 3
发布时间：2023-12-18 - 摘要：The microstructure of annular parts in centrifugal casting has been observed, in which hypereutectic high chromium cast iron semi-solid slurry prepared by slope cooling body method is used. The results indicate that not only segregation phenomenon of primary carbide in the semi-solid structure but also sharp dividing line of the segregation, where the dividing line locates at the distance of about 6 mm from the radial outer face of the annular parts, can be observed. At the given experimental condition, the shrinkage porosity tendency in the structure can only be partially eliminated by centrifugal forces. The dividing line of shrinkage porosity appearance in the microstructure also locates at the distance of about 6mm from the radial outer of the annular one, that is, as the distance from the radial outer of the annular one is less than 6mm, there are no shrinkage porosities in the radial area, contrarily, there are shrinkage porosities.关键词：Hypereutectic High Chromium Cast Iron;Semi-solid Slurry;Centrifugal Casting;Microstructure Segregation;Shrinkage Porosity
- 2
- |
- 186
- |
- 1
发布时间：2023-12-18 - 摘要：Numerical simulation of filling and solidification of large aluminum alloy support frame in indirect casting was conducted based on FDM. Based on analysis of simulated results, the rational pouring temperature of 700 ℃, and injected velocity of 10 m/s, are determined. Meanwhile, the die structure and processing design are completed, and the die is made. The origination of casting defects in trial-production of the aluminum alloy support frame is approached. It was found that the gas hole and oxidized slag are dominant in the casting defects. The support frame with high quality and performance can be manufactured by adjusting the proportion of the release agent, and by decreasing the spraying thickness of the release agent and by shortening the cycling time of the squeezing process.关键词：Indirect Squeezing Casting;Aluminum Alloy Support Frame;Numerical Simulation;Trial-production;Processing Parameters
- 2
- |
- 235
- |
- 3
发布时间：2023-12-18 - 摘要：Effects of P modification on primary Si in hypereutectic Al-Si die casting alloy with different cooling rates were investigated. It is revealed that the tendency of size decrease of primary Si in hypereutectic Al-Si alloy after and before P modification is very similar with increasing in cooling rate, where both have a sharp transition zone. P modification can greatly promote the refinement of the primary Si in the alloy with different cooling rates, because there exists a region between two change curves of primary Si size after and before P modification. Under the same cooling rate conditions, the refinement effects can be improved by 42.7% after P modification, and P still as good modification effects on primary Si with high cooling rate （ casting thickness of 1mm）. The size of primary Si can be significantly refined with P modification under rapid solidification conditions. Al-P master alloy is an excellent modifier for hypereutectic Al-Si die casting alloy.关键词：P Modification;Cooling Rate;Al Die Casting Alloy;Primary Si
- 2
- |
- 298
- |
- 2
发布时间：2023-12-18 - 摘要：The availability of compressor piston in squeezing casting has been researched by comparing different squeezing casting ways. The results show that the direct squeezing casting is favorable for ensuring casting quality and improving production efficiency, while in indirect squeezing casting,liquid alloy should be flowed into the cavity from thick-wall at two-end of the work piece, where the side-drawing-core discharging mechanism is adopted in the mould.关键词：Squeezing Casting;Compressor Piston;Mould
- 2
- |
- 137
- |
- 2
发布时间：2023-12-18 - 摘要：A corresponding gating system for die casting die can be designed based on characteristics of different component structure, such as ring pouring runner, center expanding runner, outer runner, collection wastway and other running gating system. However, all these gating systems have demerits. The general principle of designing gating system for the die casting die is that the liquid aluminum alloy in the mould cavity flows smoothly as possible to avoid direct impaction against core, and the parting surface should not be closed at once, which is beneficial to transferring of the pressure to keep good filling and exhaustion.关键词：Aluminum Alloy;Die Casting Die;Gating System
- 3
- |
- 318
- |
- 8
发布时间：2023-12-18 - 摘要：Now the investment casting only was used to produce the parts with low several kg in weight because of its limitation of processing characteristics. It was reported that the maximum weight of production-volume investment castings at home is only 260 kg. Associated parts for hydraulic pump with 670700 kg in weight and 1 059 mm ×790 mm in height and width, subjected to water pressure of 11.6 MPa, have been produced successfully in investment casting from an investment plant at the Guangzhou, which is a breakthrough in investment casting process.关键词：Hydraulic Pump;Investment Casting;Colloidal Silic Sol-Sodium Silic Mold Shell;Baking
- 2
- |
- 483
- |
- 3
发布时间：2023-12-18 - 摘要：The profile of the 26 st conference of investment casting at the European was introduced including marke news,technological events and exposition as well as vist.There are about 210 enterprises devoting in investment casting at the north American,and are about 600 enterprises at the Asian,and are approximately 200 enterprises at the European,whose total turnover is about 6.85 billion dollars.The tendency of the world’s investment casting is described from the viewpoints of processing innovation,operation automation,automatic on-line control,and so on.关键词：Investment Casting;Market News;Technological Events
- 2
- |
- 369
- |
- 2
发布时间：2023-12-18 - 摘要：Evolutions of microstructure of AZ91D magnesium alloy in lost foam casting at different pouring temperatures under vibration and vibration+semi-solid heat treatment conditions have been observed. The results show that the microstructure of the AZ91D magnesium alloy in lost foam casting can be obviously refined by vibration at different pouring temperatures, and the finest grain size can be observed by vibration force of 1.5 kN at the pouring temperature. The microstructures of both the vibrated and common samples treated by semi-solid isothermal condition can be spheroidized, and the microstructures would be coalesced to growth, in which the optimized semi-solid heat treated parameters are at holding time for 10 min at 570 ℃.关键词：AZ91D Magnesium Alloy;Lost Foam Casting;Vibration Solidification;Semi-solid Heat Treatment;Microstructure Evolution
- 2
- |
- 177
- |
- 3
发布时间：2023-12-18 - 摘要：The spot-welding electrode has been made of prepared 0.6Al2O3/Cu composites by internal oxidation, and its installment experiment and microstructure analysis have been conducted. Nano-fined Al2O3 particle in the composites can be uniformly distributed into the Cu matrix. The spot-welding electrode made by the composites has the advantages of high plastic deformation resistance, excellent corrosion resistant and high recrystallization temperature as well as excellent adhesive resistant due to the high hardness and good thermal-stability and chemo-stability, whose service life is 35 times higher than that of the Cu-Cr-Zr electrode.关键词：Electric Welding;Spot-welding;Electrode;Al2O3/Cu Composites
- 2
- |
- 90
- |
- 6
发布时间：2023-12-18 - 摘要：Phase constituent and microstructure of a new particle reinforced Al matrix composites have been observed by XRD and SEM, which is prepared by molten reaction based on a new developed in-situ Al-K2ZrF6-KBF4 system. The results show that there exist ZrB2 and Al3Zr particles with size of 14 μm uniformly distributed into the synthesized composites, in which the sectioned morphology of the ZrB2 particle is similar to regular hexahedron. Tensile testing indicates that tensile strength and yield strength of the （Al3Zr+ZrB2）p/Al composites can be increased with increasing in reactive additive. With the reactive additive of 20% （weight）, the ultimate tensile strength and yield strength of the composites are 152.3 MPa and 112.3 MPa, respectively, improved by 95.2% and 167.3%, compared with those of the aluminum matrix, 78.0MPa and 42.0 MPa.关键词：Al-Zr-B System;Al Matrix Composites;Direct Melt Reaction;Microstructure and Properties
- 2
- |
- 251
- |
- 4
发布时间：2023-12-18 - 摘要：Effects of loading at an elevated temperature and elevated temperature on dry sliding wear behavior of in-situ （TiB2+Al3Ti）/Al- 4.5Cu composites prepared by mixture salt reaction method have been investigated against spheroidal graphite cast iron. The results show that the wear resistance of in-situ （TiB2+Al3Ti）/Al-4.5Cu composites is superior to that of the matrix alloy at a high temperature （100250 ℃）. Under the condition of 200 ℃, the wear loss of the composites increases slowly at a lower load of 30 N, while it rises fastly with the load increasing to 60 N. The in-situ （TiB2+Al3Ti）/Al-4.5Cu composites are appropriate to working at below 200 ℃ due to the wear loss increasing sharply with the load of 30N at the temperature of over 200 ℃.关键词：In-situ （TiB2+Al3Ti）/Al-4.5Cu Composites;Dry Wear Behavior;Wear Resistance
- 2
- |
- 89
- |
- 3
发布时间：2023-12-18 - 摘要：Microstructure and mechanical properties of the in-situ synthesized A356/TiB2 composites have been investigated. It was revealed that in-situ reinforced particle can be uniformly distributed into the matrix without interfacial reaction, and the strength of the composites is increased with increasing in reinforced particle content. Compared with that of the matrix alloy, the tensile strength and elastic modulus of the composites with 6% and 8% volume fraction are improved by about 28% and 35%, respectively. The fragile fracture occurs in reinforcement clusters and debonding of the interface between particle and matrix are responsible for the initiating and propagating micro-crack, resulting in fracture of matrix in the vicinity of interfaces and decrease of ductility of the composites.关键词：Al Matrix Composites;In Situ;TiB2;Microstructure;Tensile Strength;Fracture
- 2
- |
- 811
- |
- 13
发布时间：2023-12-18 - 摘要：The change of structure, hardness and wear resistant of remelted hypereutectic Al-Si alloy has been observed by remelting surface of the alloy piston with CO2 continuous transverse-flow laser. The results show that the microstructure of remelted alloy consists of remelting zone, transition zone and matrix zone. Compared with that in matrix zone, the grain size in transition zone is obviously refined, where primary Si is converted from bulky polygonal or square into cell, and eutectic Si is transformed from needle-like strip into fine particle. The hardness of surface remelting zone is increased by 40 Hv, superior to matrix in wear resistant. The refinement mechanism of the remelting zone is analyzed.关键词：Laser Remelting;Hypereutectic Al-Si Alloy;Microstructure;Properties
- 2
- |
- 284
- |
- 2
发布时间：2023-12-18 - 摘要：Effects of pulse electric current on directional solidification structure of Al-4.5Cu alloy have been observed. The results revealed that with increasing in peak value of pulse current and frequency, columnar crystal in the Al-Cu alloy is breakdown to convert strip into discontinuous net to disappear its directional orientation. In addition, the space between columnar crystal is decreased with the increase of the peak value and frequency. The strong turbulence resulted from generated pulsed magnetic force and Joule heat effect during the introduction of pulse electric current are responsible for the disappearance of the directional orientation.关键词：Pulse Electric Current;Al-Cu Alloy;Directional Solidification;Columnar Crystal
- 2
- |
- 306
- |
- 5
发布时间：2023-12-18 - 摘要：Microstructure and mechanical properties of as-cast Be-Al alloy with different Ni content have been investigated by tensile testing, OM and TEM. The results reveal that the microstructure of as-cast Be-Al alloy consists of Be phase embedded into Al phase matrix, where Ni is distributed into Be phase to strengthen the matrix alloy. Ni content has greatly affected the ambient tensile strength, yield strength and hardness. The optimized comprehensive mechanical properties can be obtained by adding 4% Ni. The fracture morphology is composed of ductile rupture of Al phase and quasi-cleavage rupture of Be phase.关键词：Ni;Be-Al Alloy;Mechanical Properties;Rupture Model
- 2
- |
- 128
- |
- 5
发布时间：2023-12-18 - 摘要：Effects of aging on mechanical properties of severe cold plastic deformation 2 024 aluminum alloy have been examined by mechanical tensile test, TEM observation. The results show that aging response rate of severe cold plastic deformed Al alloy is improved, which approaches to the ultimate tensile strength with aging time of 20 min, decreased by 6 min than that of T6 treatment. Aging curves of the alloy exhibits two peak, in which the maximum strength, such as tensile strength of 580 MPa, elongation of 9.2%, can be observed at the first peak that occurs in aging time about 40 min, and the second peak can be generated at aging time about 120 min. In addition, the σ 0.2 /σb at the second peak is significantly higher than that of at the first peak. Elongation of the alloy shows a multi-stage change, where elongation is more than 8% when aging time is below 40 min, while elongation is less than 6% when aging time is more than 60 min. Furthermore, the elongation of the alloy retains a constant with increasing in aging time, which indicates the existence of critical aging time for the sever cold plastic deformed 2 024 alloy.关键词：2024 Aluminum Alloy;Severe Cold Plastic Deformation;Aging;Properties
- 2
- |
- 600
- |
- 9
发布时间：2023-12-18 - 摘要：Protections of HFC-152a atmosphere on Mg and its alloy during melting have been investigated, and the protection mechanism is analyzed. The results show that the atmosphere containing 0.001 mol/L HFC-152a can better protect the Mg and its alloy during melting. The higher the gas concentration is and the lower the melting temperature is, the better the protection effects are. The TEM and XRD analysis show that sound oxidized film is composed of MgO and MgF2, possessing better protection effects on the magnesium and its alloy.关键词：HFC-152a;Atmosphere Protection;Magnesium Alloy;SF6
- 2
- |
- 107
- |
- 3
发布时间：2023-12-18 - 摘要：A new free-cutting brass was developed by substituting Pb for Bi with trace Re addition, which keeps free-cutting ability of traditional brass. The results show that major Bi is free state is uniformly distributed in β phase, and a few Bi distributed about crystal boundary make more and more Bi particle, which improves the cutting performance. It is concluded that the Bi can completely replace Pb, obtaining free-cutting brass.关键词：Free-cutting;Brass;Mechanism
- 2
- |
- 144
- |
- 7
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