最新刊期
卷 ， 期 5 ， 2008
- 摘要：Effects of Cu content including 1.5%,2.5%,3.6%,4.5% on polynary eutectic copper-rich phases in cast Al-7Si-xCu-0.5Mg alloys and the dissolution characteristics of the phases were investigated by differential scanning calorimerty （DSC） and back-scattered SEM-EDX analysis with variation of solution temperature and time. The results indicate that quaternary or ternary eutectic reaction occurs in all tested alloys at 510 ℃ and 525 ℃ under the condition of un-equilibrium solidification,in which polynary eutectic copper-rich phase Al2Cu phase is created. Both ternary eutectic reaction of the alloy with 1.5% and 2.5% Cu content and quaternary eutectic reaction of the alloy containing 3.5% Cu at 510 ℃ are mestable eutectic reaction,in which mestable eutectic Cu-rich phase can be fully dissolved into the matrix by primary solid solution treatment at 500～505 ℃ to some time,the melting temperature of the alloy was increased to 542 ℃,525 ℃ and 521 ℃,respectively. In addition,the eutectic reaction of alloy containing 3.5% Cu and containing 4.5%Cu at 510 ℃ and 525 ℃ is a nature process in equilibrium solidification. The results show that the solution hardening effects of the Al-7Si-xCu-0.5Mg cast alloy containing Cu in range of 1.5% to 3.5% can be strengthened by increasing temperature of secondary solution treatment in two-step-solution treatment,while the alloy containing 4.5% Cu should be treated at less than 510℃ to prevent the melting of the eutectic phase with low smelting point in the alloys.关键词：Al-Si-Cu-Mg Cast Alloy;DSC;Cu-Rich Phase;Solution Treatment
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发布时间：2023-12-18 - 摘要：Mg-11Al-1.2Zn alloys containing 0.3% Sc were prepared by ingot metallurgy. The effects of scandium addition on the mechanical properties and microstructure of the as-cast alloy have been investigated by X-ray diffraction（XRD）,optical microscope（OM）,scanning electron microscope （SEM） and tensile testing. The results indicate that the microstructure of the alloys is mainly composed of primary α-Mg phase,Mg17Al12 phase and MgAlSc phase,in which the grain size and morphology and distribution of Mg17Al12 phase can be evidently improved with Sc addition. In addition,the tensile strength of the alloy at room temperature can be increased by more than 10% with the Sc addition.关键词：Mg Alloy;Scandium;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The Si3N4/AlN-Al composites with different ceramic contents were successfully prepared in N2 atmosphere by optimized pressure-free infiltration process at 950 ℃ for four hours. The flexural strength,compressive strength,fracture toughness and hardness of the prepared composites were measured to understand the effects of ceramic content on mechanical properties and fracture morphology of composites. The results reveal that with the increase of Si3N4 content in the performs from 30.2% to 60.6% （in volumetric fraction）,the compressive strength,flexural strength and hardness of the composites can be increased from 620 MPa to 1 728 MPa,from 429.8 MPa to 672.4 MPa and from 55 to 83,respectively,with the decrease of fracture toughness from 10.55 MPa·m1/2 to 2.26 MPa·m1/2. The crack in the Si3N4/AlN-Al composites is formed at!three types of zones including remained coarse Si3N4 particles,loosen sections and coarse Mg2Si phase.关键词：Pressure-free Infiltration;Si3N4;Ceramic Metal Composites;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Effects of rolling temperature and cycle numbers on microstructure and properties of the AZ31 magnesium sheets during accumulative rolling-bonding （ARB） were investigated,and the mechanism of grain refinement in AZ31 magnesium alloy during ARB was described. It is found that the average grain size is decreased with the temperature increasing from 250 ℃ to 400 ℃ after the first cycle period in ARB. The AZ31 sheets with average grain size of 1.3 μm and elongation of 25.2% as well as tensile strength of 300 MPa can be obtained by ARB at 400 ℃ with 50% thickness reduction per pass after the second recycle during ARB.关键词：Accumulative Rolling-bonding （ARB）;AZ31 Magnesium Alloy;Grain Refinement;Microstructure
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发布时间：2023-12-18 - 摘要：Effects of different rolling speeds including 12,15 and 20 m/s and different compositions on the microstructure and magnetostrictive properties of Fe-Ga alloy prepared by melt-spun method have been examined. The results reveal that the microstructure and magnetostrictive properties of the alloys are closely related to the composition and cooling rate during melt-spun process. The maximum magnetostrictive properties of Fe83Ga17 reaching up to 6.5×10-5 can be obtained with a cooling rate of 12 m/s. The X-ray diffraction indicates that the microstructures of all alloy ribbons are composed of Fe solid solution. The ribbon observation reveals that the crystal along thick direction of ribbons exhibits orientation to some extent. The magnetostriction of the ribbons is related to the high lattice distortion and shape anisotropy.关键词：Fe-Ga Alloy;Melt-spun;Lattice Distortion;Magnetostriction
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发布时间：2023-12-18 - 摘要：Effects of homogenization treatment on microstructure and properties of 7B50 aluminum alloy have been investigated by optical microscope（OM）,XRD（X-ray diffraction） and SEM （scanning electron microscope）. The results indicate that the content of residual un-equilibrium eutectic phase with more uniform distribution which is mainly composed of immiscible Fe-eutectic phase in the alloy homogenized by two-step homogenization treatment is much less than that homogenized by one-step homogenization treatment. Compared with that precipitated from the alloy homogenized by one-step homogenization treatment,the secondary phase Al3Zr particle precipitated from the alloy homogenized by two-step homogenization treatment exhibits more dispersive and uniform distribution with slight coarse,which is helpful to the improvement of strength of the alloy.关键词：Homogenization Treatment;7B50 Alloy;Microstructure and Properties
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发布时间：2023-12-18 - 摘要：The processing parameters of salt-composites modification on ZA27 alloy have been determined,which was verified by practical product. The results indicate that the Ti+B mixed modification can remarkably improve the elongation of ZA27 under the condition of non-deteriorating tensile strength,which is a effective modifier. The production verifies that the mechanical properties of ZA27 alloy can approach to that of the bronze parts.关键词：ZA27 Alloy;Salt-composite;Modification
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发布时间：2023-12-18 -
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- 摘要：Effects of the configuration of feed tip nozzle on flow field and temperature field in twin-rolling casting strip of magnesium alloy melt in cavity were described. Based on the SOLA-VOF finite differential method,the coupled model of flow field with temperature field in twin-rolling casting strip of magnesium alloy melt has been established to simulate the effects of different nozzle cavity structure on flow velocity of the magnesium melt and temperature distribution in magnesium melt under the same initial condition including the same height and temperature of the molten magnesium alloy in front box. The results reveal that decreasing the size and increasing numbers of the spacer are helpful to obtaining uniformly distributed flow field and temperature field in cavity of feed tip nozzle. The results are well in agreement with simulated ones,and the magnesium alloy strip with desirable quality can be produced based on simulated results modifying the structure of feed tip nozzle.关键词：Magnesium Alloy;Twin-rolling Casting;Configuration of Feed Tip Nozzle;Numerical Simulation
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发布时间：2023-12-18 - 摘要：The modeling of non-isothermal dendrite growth in Pb-Sn alloy was conducted based on the phase field method to visualize the evolution of interface morphology of dendrite and to examine the effects of phase parameters on it. The results indicate that the dendrite mosphology is dependent on the under-cooled degree,coupled parameters and anisotropy value. The trapped melt packets and side branches can be greatly suppressed by an anti-trapping current. Furthermore,the relationship between anisotropy and dendrite tip velocity was described.关键词：Phase Field Method;Pb-Sn Alloy;Non-isothermal;Dendrite Growth;Tip Velocity;Anti-trapping Current;Anisotropy
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发布时间：2023-12-18 - 摘要：The mould for magnesium alloy steering wheel can be designed by the CAE software which can predict potential defect location in die casting. Based on analysis of simulated results,the die casting die was modified and optimized. The results show that the defects in the die casting magnesium steering wheel can be greatly eliminated by using modified process,improving the quality of the castings.关键词：Numerical Simulation;Die Casting;Defects
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发布时间：2023-12-18 - 摘要：The bigger size A356 aluminum alloy semi-solid slurry with spherical primary α-Al phase was prepared by low super-heating pouring combining with traveling wave electromagnetic stirring. The effects of pouring temperature,stirring frequency and stirring power on the microstructure of semi-solid A356 aluminum alloy slurry were observed. It is found that with decreasing in pouring temperature,the primary α-Al phase in the semi-solid slurry becomes more and more round,and the more desirable microstructure in the semi-solid slurry can be prepared with the stirring frequency equal to or more than 10 Hz. With increasing in stirring power,the more round primary α-Al phase can be formed in the semi-solid slurry,which is attributed to the rosette-like primary α-Al phase in the semi-solid A356 alloy slurry intensely subjected to the man-made temperature fluctuation to result in the root melting of dendrite. The fine spheroidized primary α-Al phase can be successfully prepared with pouring at 620 ℃ and stirring at 10 Hz as well as 1.72 kW.关键词：Semi-solid;A356 Alloy;Traveling Wave Electromagnetic Stirring;Low Temperature Pouring;Microstructure
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发布时间：2023-12-18 - 摘要：Effects of technological parameters including pouring temperature,stirring power and stirring time on microstructure of semi-solid Al-30Si alloy slurry prepared by low super-heat pouring combining weak electromagnetic stirring were analyzed. The results indicate that compared with that prepared by conventional casting,the semi-solid Al-30Si alloy slurry prepared by low super-heat pouring combing with weak electromagnetic stirring exhibits more desirable structure morphology,in which the minimum and maximum size of primary Si can be decreased from 16 μm to 7 μm and from 296 μm to 23 μm,respectively,and the average size of primary Si phase can be decreased from 138.8μm to 11.49 μm,and the alloy with more uniform distribution in slurry become more and more spheroidization. The morphology,distribution and size of primary Si in semi-solid Al-30Si alloy slurry are deeply dependent on the pouring temperature,stirring power and stirring time.关键词：Low Super-heat Pouring;Weak Electromagnetic Stirring;Semi-solid;Al-30Si Alloy;Microstructure
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发布时间：2023-12-18 - 摘要：The foundation and application of semi-solid processing were surveyed including continuous casting process,reheating of billet,the rheological behavior of semi-solid slurry,die casting process of semi-solid slurry,the heat treatment of die castings,numerical simulation and production of automobile parts. The microstructure of billets prepared by vertical continuous casting exhibits evident spheroid,and average tensile strength and elongation of the slurry reach up to 250 MPa and 15%,respectively. The holding time should be shortened as possible to keep fine and spheroidized structure in slurry during reheating process under the condition of uniform temperature field. The tensile strength and elongation of semi-solid die castings reach up to 330 MPa and more than 10%,respectively. The future development in industry and fundamental understand was proposed.关键词：Semi-solid Processing;Aluminum Alloy;Numerical Simulation;Rheological Behavior;Automobile Part
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发布时间：2023-12-18 -
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- 摘要：The microstructure and mechanical properties of low pressure casting magnesium alloy wheel have been investigated. The results reveal that primary α-Al phase in the microstructure is dendrite,and fine eutectic Si particle is distributed along the grain boundary. In addition,the grain size at different location of wheel is obviously different. There exists needle-and fishbone-like Fe based compound,oxidized film and shrinkage hole as well gas hole in the microstructure of the magnesium alloy wheel. The tensile strength,yield strength and elongation of the wheel in die casting are 303 MPa,225 MPa and 14.3%,respectively,which are obviously superior to those in sand casting and in investment casting.关键词：A356 Alloy;Wheel;Low Pressure Casting;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Ways of improving service life of die casting die were proposed including structure design of die castings,design of die casting die,the selection of component materials,working and assembling of mould,heat treatment of materials as well as selection of processing parameters. It is pointed out that the die castings should be designed to thin-walled components with uniform thickness as possible,in which the round angle should be adopted at turn corner to avoid deep and narrow slot. The components in die casting die should be ensured rigidity and strength,and the impaction of liquid metal should be prevented at gating system design,and so on. Steel billet should be annealed after forging,and the surface of cavity in die casting die should be strengthened.关键词：Die Casting Die;Service Life;Heat Treatment;Way
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发布时间：2023-12-18 - 摘要：K403 alloy gas turbine nozzle was produced by investment casting,and the casting process has been investigated systematically. The results show that the developing period of the K403 alloy gas turbine nozzle can be greatly shortened with the reduction of production cost by rapid prototyping technology to produce investment pattern. The castings have desirable metallurgical quality and entirely meet the requirements of the design and use by adopting the united-inpouring gating system with higher pouring and shell mold temperature.关键词：K403 Superalloy;Investment Casting;Rapid Prototyping;Gating System
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发布时间：2023-12-18 - 摘要：It played evident role for production of investment castings since middle-temperature wax,shell mold made of sol silicate-ZrO2 slurry-ZrO2 face layer and dewaxing by vaporization were used by the end of 1980’s. However,ZrO2 sand （powder） possesses expensive price and limited resource,resulting in the high production cost. The shell-making method of special sand （powder） substituted for ZrO2 sand （powder） was described. The surface roughness and size precision of the investment castings are very desirable,obviously reducing the production cost.关键词：Special Sand （Powder） for Investment Casting;Slurry;Coating
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发布时间：2023-12-18 - 摘要：The copper cladding aluminum with desirable as well as and copper at outer layer and aluminum at inner layer was successfully produced by a self-developed continuous core-filling casting machine with appropriate processing parameters. The copper cladding aluminum wires with different diameters were produced by static squeezing and withdrawing compound billets. The micro-hardness,electric conductivity and mechanical properties of the composites were measured. The results meet the requirements of the national standard.关键词：Copper Cladding Aluminum;Continuous Core-filling Casting;Composites
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发布时间：2023-12-18 - 摘要：In-situ （Al2O3+Al3Zr）p/A356 composites were synthesized by direct melting reaction combining with high intensity ultrasonic. The microstructure and properties of synthesized composites were investigated by XRD（X-ray diffraction） and SEM （scanning electron microscope）. It is found that the reinforcements Al2O3 and Al3Zr with average size of 1μm can be observed in the matrix alloy,which is uniformly distributed into the composites. Eutectic Si phase in A356 alloy can be broken into Si particle by high intensity ultrasonic,exhibiting great refinement effects. The tensile strength of ultrasonic treated composites reaches up to 381.4 MPa,which is increased by about 20% compared with that of ones without treated by high intensity ultrasonic.关键词：High Intensity Ultrasonic;In-Situ Reaction;Aluminum Matrix Composites;Mechanical Properties
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发布时间：2023-12-18 - 摘要：We have developed a counter-gravity withdrawal casting （CWC） to understand porosity formation in Sr modified A356 alloy without degassing. It is found that with distance far from the crystallizer,the number of large pore with the size larger than 0.5 mm in cross section is firstly increased from 0 to 7 then decreased to 1,while the number of small pore with size less than 0.5 mm is firstly decreased from 2 to 1 then increased to 4,however,the porosity rate in transverse section is increased from 0.3% to 2.5% then decreased to 0.9%,which is attributed to the decrease of temperature gradient with decreasing in cooling rate far from the crystallizer.关键词：Counter-gravity Withdrawal Casting;Pore;Al-Si Alloy;Porosity Rate
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发布时间：2023-12-18 -
Microstructure and Phase Constituent of Microarc Oxidation Ceramic Coating on the Surface of ZAlSi12
摘要：Effects of NaOH concentration in the electrolyte on the thickness of micro-arc oxidization coating on ZASi12 alloy were observed. The microstructure and phase constituent of the ceramic coating were analyzed by SEM （scanning electron microscope） and XRD（X-ray diffraction）. The results reveal that a good coating with thickness of 169 μm can be obtained in electrolyte with 2.0 g/L NaoH concentration. It is found that there exist obvious electric discharge channels in the coating with the coating and the substrate inserting into each other. The film is composed of α-Al2O3 phase and γ-Al2O3 phase.关键词：ZAlSi12 Alloy;Micro-arc Oxidation;Microstructure;Phase Constituent- 2
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发布时间：2023-12-18 - 摘要：The relationships between characteristic value of cooling curve and the porosity of 319 Al alloy as well as the content of modifier Sr have been detected by thermal analysis. The results show that the temperature difference is closely related to the porosity in castings. With increasing in porosity,the temperature difference is increased. The alloy can be totally modified with 0.008% Sr addition while the modification effects can be deteriorated with the Sr addition more than 0.03%.关键词：Thermal Analysis;319 Aluminum Alloy;Porosity;Modification
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发布时间：2023-12-18 - 摘要：Effects of mould structure and pouring temperature on mechanical properties of Mg-6Al-2.4Y alloy were examined by microstructure analysis and mechanical testing. The results reveal that the optimization of mould structure can improve the mechanical properties of the alloy due to decreasing the defects in the alloy. The shrinkage porosity （hole） can be created in the alloy with pouring temperature either excessively low or excessively high,however,proper pouring temperature can eliminate the shrinkage porosities （holes） in the alloy,and refine the grain size as well as improving the tensile strength of alloy.关键词：Pouring Temperature;Permanent Mold;Magnesium Alloy;Mechanical Properties;Microstructure
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发布时间：2023-12-18 - 摘要：The corrosion behavior of ZA27 alloys in 35 g/L NaCl solution has been examined by electrochemical and immersion corrosion tests. The effects of Cu and Sb on the Tafel curves and electrochemical parameters,including free corrosion potential,electric resistance of linear polarization,corrosion current,of the ZA27 alloy have been investigated. The surface morphology of the alloy after corrosion treatment has been observed by SEM （scanning electron microscope） and EDAX. The results indicate that low Cu content can improve the corrosion resistance of the ZA27 alloy,which is attributed to Cu making the free corrosion potentials shift to positive to decrease the corrosion current density,however,excessive Cu content can deteriorate the corrosion resistance. The free potential of the tested alloy shifts to negative to increase the corrosion current density with the increase of Sb,declining the corrosion resistance of the ZA27 alloy.关键词：ZA27 Alloy;Corrosion Resistance;Free Corrosion Potential
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发布时间：2023-12-18 - 摘要：Effects of solid solution,cold deformation and aging on micro-hardness and electrical conductivity of Cu-Ni-Si alloy were investigated. Meanwhile,effects of Ag and P on properties of Cu-Ni-Si alloy were examined. The results reveal that minor P content can effectively improve the microhardness of alloy with the slight decrease of electric conductivity. Minor Ag can increase both micro-hardness and electric conductivity of the alloy.关键词：Cu-Ni-Si Alloy;Lead Frame;Micro-Hardness;Electric Conductivity;Ag;P
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发布时间：2023-12-18 - 摘要：The tarnishing of sterling silver alloys deteriorated the surface quality of jewelry greatly. The principles and methods of designing the alloying compositions of anti-tarnishing silver alloys were approached including multi-elements and small quantity alloying,meeting the requirements of different manufacturing properties,various strengthening approaches,wide processing maneuverability,low cost and friendly environment,and so on. It is pointed out that the composition of anti-tarnishing sterling silver alloy should be designed based on three preliminary procedures. Based on above principle,the composition range of the alloy suitable for different producing techniques were determined,and their properties were measured in laboratory and in industrial production,respectively. The results show that the series JIS silver alloys have excellent anti-tarnishing and manufacturing properties,exhibiting desirable comprehensive properties.关键词：Anti-tarnishing;Silver Alloys;Alloy Composition
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发布时间：2023-12-18 -
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