最新刊期
卷 30 ， 期 1 ， 2010
- 摘要：Microstructure and phase formation as well as its distribution in the as-cast Cu-0.5Te-0.2Zr alloy were investigated by optical microscope（OM）,field-emission scanning electron microscope（FE-SEM）and energy dispersive spectrometer（EDS）.The results show that there exist two types of tellurium-rich phases in the alloy including rod-shape Cu2Te phases distributing in grain boundary and a little amount of ternary eutectic structure.The existing form of the Zr in the alloy includes undissolved phases,secondary phase,Cu5Zr binary eutectic and ternary eutectic structure.Undissolved phase exists as single particle in the grain,and fine secondary phase particle is uniformly and dispersedly distributed in the matrix.Besides,binary eutectic and ternary eutectic phase exhibits irregular block distribution.关键词：Cu-Te-Zr Alloy;Microstructure;As-cast;Phase
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发布时间：2023-12-18 - 摘要：Mg matrix composites（Al63Cu25Fe12）p/AZ91 with 10%（Al63Cu25Fe12）p in volumetric fraction was successfully prepared by die casting in condition of CO2/SF6 protection,in which the approximately 200 mesh quasi-crystalline Al63Cu25Fe12 powder was poured into the AZ91 molten alloy and then rapidly stirred for 30 min at 720℃.Reaction of quasi-crystalline particle with the matrix alloy was analyzed with the help of SEM（scanning electron microscope）and EDAX（energy spectrum diffraction analysis）,and effects of heat treatment on properties of the composites were evaluated.The results reveal that quasi-crystalline I phase is decomposed during stirring process,and Cu atom free decomposed from quasi-crystalline I phase is diffused into the matrix alloy to react with Al atom in the matrix alloy,and created intermetallic compound is distributed around the quasi-crystalline particle,meanwhile,Mg atom is emerged into the powders to substitute the sites of Cu atoms.Aging peak value of the composites is significantly delayed,exhibiting solution and aging characteristics distinctly different from the matrix alloy.Mechanical properties of the composites after hot extrusion and heat treatment are obviously improved,where tensile strength is increased from 189.54 MPa of as-cast AZ91 alloy to 359.38MPa,however,plasticity is slightly decreased.关键词：Al63Cu25Fe12 Quasi-crystalline Particle;Die Casting;AZ91 Magnesium Alloy;Metal Matrix Composites
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发布时间：2023-12-18 - 摘要：The cooling process of the Al-Si alloy were analyzed by a model,in which the heat transfer equation of atomized alloy droplets coupling with motion equation was considered,to understand effects of droplet size,initial gas velocity,super-heat of the melt on cooling process and microstructure of the A390 alloy.It is found that,with decreasing in size of droplet,the obtained cooling rate and under-cooled rate are raised.When the droplet size is decreased to below a critical size,temperature change and microstructure of the droplets are sharply transformed.Precipitation of primary phase can be restrained by increasing initial velocity of atomized gas and decreasing superheating rate of melt,which is beneficial to the refinement of microstructure of Al-Si alloy.关键词：Atomized Droplets;Solidification;Critical Size;Metastable Structure
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发布时间：2023-12-18 -
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- 摘要：Morphology and microstructure of over-sprayed powder in spray forming high Mn ZA35 alloy were observed by SEM（scanning electron microscope）,and particle size in the powder was analyzed,and cooling rate of the powder was calculated,meanwhile,phase constituent in the alloy was analyzed by XRD（X-ray diffraction）.The results indicate that with decreasing in size of the over-sprayed powder,the roundness of the power is increased.The average grain size of the powder prepared by atomization at 1.0MPa is refiner than that of one at 0.8MPa.The average cooling rate of the powder reaches 104～105 K/s.Microstructure of the ZA35 alloy containing high Mn is composed of α-Al phase with rich Mn element and η-Zn phase with rich Mn element.关键词：Spray Forming;Over-sprayed Powder;Morphology;ZA35 Alloy Containing High Mn
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发布时间：2023-12-18 - 摘要：Laser cladding experiment was conducted on AA6063 aluminum alloy by pre-coating Al and Ti powder with 3∶1 in atomic ratio.The results reveal that coating with smooth surface and crack-free as well as porous free can be obtained by using proper laser power and scanning velocity.The coating is composed of Al3Ti dendrite and interdendritic pure Al phase,in which Al3Ti dendrite exhibits fine structure nearby surface of the samples and it exhibits coarse structure nearby the matrix,and desirable metallurgical bonding between the coating and matrix can be observed.The hardness of the coating reach up to Hv500,significantly improving the surface performance of the aluminum alloy.关键词：Laser Cladding;Aluminum Alloy;Al3Ti Coating
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发布时间：2023-12-18 - 摘要：Activation effects of η precipitates in the Al-5Zn-0.02In-1Mg-0.05Ti sacrificial anode alloy were examined by SEM（scanning electron microscope）,TEM（transmission electron microscope）,XRD（X-ray diffraction）and electrochemical properties testing.The results reveal that the main precipitates are the MgZn2 phase（η phase）.The η precipitates are taken as anodic phase to form a micro-corrosion cell with α-Al matrix in 3.5%NaCl solution,leading to the self-dissolution of the precipitates.Dissolved Zn2+ is deposited around the pit to enhance the occurrence of oxidized defects and to promote the exfoliation of oxidization film.The η phases are acted as the activation center for alloy dissolution,resulting in the whole dissolution of the alloy by extending outward.关键词：Sacrificial Anode;η Precipitates;Corrosion;Activation
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发布时间：2023-12-18 - 摘要：Microstructure evolution of Al-Ti-C refiner during melting and solidification process was observed by the Lasertec 1LMH21 confocal scanning laser microscope and optical microscope（OM）.The results indicate that during melting process,Al matrix is firstly melted in Al-Ti-C refiner,and then lamellar TiAl3 phase and TiC phase becomes free phase in liquid aluminum,finally the TiAl3 phase is broken into fine particles,meanwhile,with increasing in holding time and in melting temperature,the broken degree is enhanced.The grain morphology of TiAl3 and TiC phase is effectively improved by re-melting process at 700～800℃.With remelting temperature more than 800℃,TiAl3 particles are coarsened to fail to refining,while TiC phase with desirable size can be obtained at a higher re-melting temperature with a subsequently rapidl solidification.关键词：Al-Ti-C Alloy;Microstructure;TiAl3;TiC;Refiner
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发布时间：2023-12-18 -
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- 摘要：The present status and application of semi-solid alloy rheocasting technologies were surveyed.The rheo-casting technologies and their future were described including semi-solid slurry preparation in the injection sleeve,the rheomolding process by a single screw,the rheomolding process by two screws,low super-heating inclined plate rheocasting,low super-heating pouring combining with weak mechanical stirring method,the continuous rheo-conversion process,low super-heating pouring combining with weak electromagnetic stirring,the serpentine channel pouring process,the melt spreading and mixing process,the rotating barrel rheomoulding machine process,the wave-like sloping plate process,rotating inclined cylinder rheomoulding process,the ultrasonic vibration process,the melt treatment and reversible electromagnetic stirring process,the sub-liquidus casting process,the swirled enthalpy equilibration device process,and the gas induced semi-solid process.关键词：Semi-solid;Rheo-casting;Alloy
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发布时间：2023-12-18 - 摘要：The shrinkage porosity in ductile iron components was not be completely eliminated by graphitizing expansion as a result of the large variation in the thickness of the component and its complexity in structure.Origination of shrinkage porosity in a marine diesel piston was visualized by numerical simulation.The sequential solidification design was established by adopting the step runner,arranging chill and riser,which was verified by numerical simulation and practical experiment.The results indicate that the shrinkage porosity（hole）in the piston can be effectively eliminated by employing sequential solidification design.关键词：Sequential Solidification;Step Runner;Ductile Iron;Numerical Simulation
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发布时间：2023-12-18 - 摘要：With filling velocity of 0.1 m/s in ingate and temperature of liquid Mg alloy and mould at 680℃ and 200℃,respectively,flow morphology of liquid Mg alloy at center of runner and end of tangential runner of step plate was simulated by numerical simulation to understand the effects of geometric shape of runner on the flow of liquid Mg alloy in squeezing casting.The results reveal that liquid Mg alloy exhibits desirable flow morphology at the center of runner,where velocity at different direction is slightly changed at varied flow distance.However,at end of tangential runner,with reducing in equivalent radius of runner and increasing in flow distance,the velocity at x and Z directions exhibits dramatically change and velocity amplitude is obviously fluctuated at filling direction,resulting in the difficulty of control to flow morphology.关键词：Magnesium Alloy;Squeezing Casting;Numerical Simulation;Runner
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发布时间：2023-12-18 - 摘要：Filling of rheo-diecasting A357 aluminum alloy and distribution of gas hole in the alloy were simulated by the Flow-3D software at different injection pressure and different injection speed,and solidification process was visualized too.The experiment was conducted to validate the simulated results.The results reveal that flow morphology of semi-solid A357 aluminum alloy melt is transformed from laminar structure into turbulence structure with increasing in injection pressure and injection velocity,meanwhile,distribution of gas hole in the solidification process is also affected.The simulated results are well in agreement with experimental ones,showing that the Flow-3D software can optimize processing parameters of rheo-diecasting A357 aluminum alloy and improve the properties of the die castings.关键词：Semi-solid;Rheo-diecasting;FLOW-3D;Numerical Simulation
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- 420
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发布时间：2023-12-18 - 摘要：Based on performance requirements of automobile air condition accessories and characteristics of semi-solid process,quasi-eutectic Al-Si alloy Al-10.5Si-2.5Cu-1.0Mg-Mn was developed.The semi-solid billets with non-dendrite structure was prepared at 583℃by low-super-heating pouring technology.Amounts of free fine nuclei with high survival rate are created in the melt with holding for some time at low temperature nearby liquidus,which is responsible for the formation of non-dendrite on the aluminum alloy semi-solid billets.关键词：Automobile Air Condition Accessories;Quasi-eutectic Al-Si Alloy;Semi-solid;Alloy Design;Billet Preparation
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发布时间：2023-12-18 - 摘要：By understanding microstructure and properties of thixo-molded AZ91D fabricated at different processing parameters,the fracture behavior was investigated.The results show that ambient microstructure of typical thixo-molded AZ91D alloy is mainly composed of un-melted α-Mg and solidified phase.The un-melted solid phase can be divided into four types,such as spherical solid particles,irregular solid particle,solid particle with liquid pool inside and solid particle with liquid alloy inside.Solidified phase includes primary α-Mg phase and eutectic phase,in which primary phase exhibits regular structure with fine grain,controlling by under-cooling rate of liquid alloy.Porosity rate is the main factor influencing the mechanical properties of the alloy with similar microstructure,while effects of microstructure on the mechanical properties of the alloy with similar porosity rate is dominant.The samples with a lower solid fraction and a finer primary solid phase exhibits acceptable properties.Crack in the sample during tensile testing is propagated along interface of un-melted solid phase and liquid phase or along primary solid phase and eutectic phase.With a higher solid fraction,crack is mainly propagated along interface of un-melted solid phase and liquid phase,resulting in the deterioration of mechanical properties,while with a lower solid fraction,crack is mainly propagated along interface of primary solid phase and eutectic phase,leading to the improvement of mechanical properties as a result of bridging effects though β phase.关键词：Thixo-molded;AZ91D Magnesium Alloy;Solid Phase;Properties
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发布时间：2023-12-18 - 摘要：Hydrogen content in aluminum alloy melt was measured with LECO RHEN602 hydrogen determinator,and microporosity size and its volumetric fraction in different location of squeezing casting aluminum alloy parts,which were produced at 40,60 and 80MPa,were measured by image analysis technology.Quantitative relationship between microporosity,volumetric fraction and applied pressure was presented.The results indicate that both microporosity size and its volumetric fraction in the parts are decreased with increasing in applied pressure.关键词：Squeezing Casting;Aluminum Alloy;Microporosity;Hydrogen Content;Applied Pressure
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发布时间：2023-12-18 - 摘要：A 5083 alloy trial-part was produced by squeezing casting.The optimized processing parameters,such as specific pressure of 125MPa,pouring at 670℃ for 15 s,were presented based on orthogonal testing and range analysis.Microstructure and mechanical properties of the squeezed parts in condition of the optimized parameters were analyzed.Compared with conventional casting parts,the squeezed casting parts exhibit finer and more uniform microstructure as well as the higher comprehensive mechanical properties,reaching up to or approaching the mechanical properties of hot forging ones.关键词：5083 Alloy;Squeezing Casting;Orthogonal Testing;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Filling and solidification for aluminum alloy housing in die casting were simulated by the ProCAST software.Distribution and change of velocity field and temperature field were visualized.Based on above simulated results,optimized design for reducing shrinkage porosity（hole）was presented.The results reveal that the shrinkage porosity（hole）in the aluminum alloy housing can be greatly reduced through decreasing pouring temperature,increasing injection pressure and reducing pre-heating temperature of the mould.The qualified aluminum alloy housing was successfully produced by adopting optimized processing parameters.关键词：Aluminum Alloy Housing;Die Casting;Numerical Simulation;Shrinkage Porosity;Shrinkage Hole
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发布时间：2023-12-18 - 摘要：In order to optimize the gating system and process parameters for aluminum alloy engine cylinder body,the ProCAST software was employed to simulate the filling and solidification process.Through analyzing the flow field and temperature field during the die casting process with two different pouring positions,an optimized gating system can be presented,which provides a reference to the design and determination of processing parameters.关键词：Cylinder Body;Die-Casting;Gating Position;Numerical Simulation;Temperature Field;Flow Field
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发布时间：2023-12-18 - 摘要：There exist 12 circumferentially equispaced dummy clubs with through-hole on a aluminum alloy bowl castings,so radial multiple core pulling should be adopted in die casting.If the angle pin-slide side core pulling mechanisms are adopted in the mould,12 angle pin-slide mechanisms should be considered for radial core pulling,which results in the complex of mould structure and un-desirable whole shape.The technical characteristics of the die casting were analyzed,and a die casting die with special structure was presented,in which radial multiple core pulling was realized by angle pin and rack and turn table mechanism,simplifying the structure of the mould.Aiming at the features of high wrapping force of casting hole to castings and thin wall,an ejector sleeve was adopted in the die casting die to pull out the castings and to obtain the smooth surface.关键词：Die Casting Die;Radial Multiple Core Pulling;Angle Pin and Rack and Turn Table Mechanism
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发布时间：2023-12-18 - 摘要：Effects of pre-precipitates on recrystallization structure and recrystallization temperature of AA3003 twin roll cast aluminum strip treated by different homogenization were investigated by optical microscope,hardness tester,scanning electron microscope and the Kelvin bridges.The results show that recrystallization structure in the cold rolled strips is closely related to the precipitated secondary phase during high temperature homogenization.The recrystallization temperature of the strips treated by homogenization at 580℃ is decreased approximately 100℃.Furthermore,fine equiaxed structure with very small size gradient can be observed in the strips after annealed at 520℃.关键词：Homogenization;Twin Rolling-casting;AA3003 Aluminum Alloy;Recrystallization
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发布时间：2023-12-18 - 摘要：Aluminum alloy castings developing status,mold-making,aluminum alloy melting,formation process,especially counter-gravity casting,were surveyed briefly.The future of aluminum alloy investment casting was presented.关键词：Aluminum Alloy;Investment Casting;Counter-gravity Casting
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发布时间：2023-12-18 - 摘要：Network ceramics reinforced aluminum matrix composites were successfully prepared by squeezing casting method,and wear behavior of the composites was examined in condition of dry friction.The results reveal that the wear resistance of the composites is greatly superior to that of the matrix alloy.Network ceramics can effectively inhibits or restrain the transformation of matrix alloy from mild wear to severe wear by subjecting to load as a result of concaving on wear surface as a supporter,meanwhile,it can disperse load to around direction to reduce the loss of matrix alloy on wearing surface resulting from plastic deformation.关键词：Network Ceramics;Aluminum Matrix Composites;Dry Friction and Wear;Squeezing Casting
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发布时间：2023-12-18 - 摘要：Effects of intermediate annealing on mechanical properties of copper cladding aluminum strip for HF cable were investigated.It is found that with increasing in annealing temperature or extending in annealing time,elongation is firstly increased and then decreased and strength of the compound is decreased.The maximum value of elongation of the compound strip reaches 35.80% with annealing at 340℃ for 3 hours.The desirable mechanical properties of the strip can be observed with intermediate annealing at 310℃ for 1.5 hours.关键词：Copper Cladding Aluminum Strip;Intermediate Annealing;Elongation;Tensile Strength
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发布时间：2023-12-18 - 摘要：The master alloy Mn-30Al containing ε-AlMn phase and the Mn-30Al alloy containing γ2-Al8Mn5 phase were prepared by vacuum quenching furnace,and microstructure of two kinds of master alloys were observed,meanwhile,effects of ε-AlMn phase,γ2-Al8Mn5 phase,Mn and Al on grain refinement of magnesium alloy were analyzed.The results reveal that refining effects of Mn-30Al master alloy containing ε-AlMn phase on the magnesium alloy are obviously superior to Mn-30Al alloy containing γ2-Al8Mn5 phase,Mn,Al.With 0.4% Mn-30Al master alloy containing ε-AlMn phase,grain size of AZ31 magnesium alloy and Mg-Zn alloy are decreased from 898 μm to 320 μm and from 320 μm to 180 μm,respectively.ε-AlMn phase can be acted as desirable heterogeneous nuclei through surface misfit calculation.关键词：Magnesium Alloy;ε-AlMn Phase;Grain Refinement;Spraying Deposition
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发布时间：2023-12-18 - 摘要：Effects of B on refining primary Si phase in hypereutectic Al-Si alloy were observed by OM（optical microscope）,SEM（scanning electron microscope）.The results reveal that B exhibits excellent refinement on primary Si phase in Al-20Si alloy.Size of primary Si phase is firstly decreased and then increased with increasing in B content,in which the smallest primary Si size can be observed with 0.065% B content.Trace Ca and Mg addition can promote the refining effects of B on primary Si phase,while C2Cl6 treatment can weaken the refining effects of B.The compounds formed from the reaction of B with Al,Si and Ca or Mg,which can be served as the nucleation substrates for primary Si phase,may be responsible for the refining effects of B on the primary Si phase.关键词：Hypereutectic Al-Si Alloy;Al-B Master Alloy;Primary Si;Refining Effects
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发布时间：2023-12-18 - 摘要：Effects of Si and Mg content and alloying elements on mechanical properties of A356 alloy were investigated.The results show that with increasing in Si and Mg content in a permissible range,mechanical properties of as-cast and T6 treated A356 alloy are improved to some extent,which is attributed to Si and Mg promoting the more creation of Mg2Si phase and increasing the numbers of eutectic phase.Furthermore,with adding alloying element,the mechanical properties of the alloy are greatly improved as a result of more effective refinement of primary Al phase and more full modification of eutectic Si phase.A356 alloy containing high Si and Mg element exhibits more sensitive to refinement and modification,tensile strength and elongation of T6 treated alloy reach up to 320MPa and 8.0%,respectively,increased by 18.6% and by 35.6%,respectively,compared with those of T6 treated alloy with low Si and Mg element.关键词：A356 Alloy;Constituent Adjustment;Alloying Element;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Failure origination of beryllium bronze for electronic trade,die casting punch and precision injection was described by analyzing difference of microstructure of various beryllium bronzes based on equilibrium diagram,and countermeasures were presented.Through adjusting constituent in the beryllium bronze,controlling key processes including melting technology,melting process,heating technology and heat treatment,and analyzing chemical composition in the ingot by XRD（X-ray diffraction）to ensure composition in a permissible range,the qualified beryllium bronze with high properties was successfully prepared.关键词：Beryllium Bronze;Mould;Failure Origination
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发布时间：2023-12-18 - 摘要：Engine cylinder,as one of the key parts for the engine,is a typical difficult-forming complicated part,which exhibits the feature not only larger size,complex structure,thin wall with un-even thickness but also narrow processing method and many influencing factors,so it is suitable for production by LFC（lost foam casting）.Mould design is a key procedure in producing engine cylinder.The desirable design can not only reduce the requirements for production conditions,but also improve the qualified rate and comprehensive performance of the parts.The mould for LFC engine cylinder with excellent structure was designed by considering the features of the parts and convenience of next-manufacturing combining with the characteristics of LFC mould,which is beneficial for improving the qualified rate and comprehensive performance of the cylinder.关键词：LFC;Engine Cylinder;Mould
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发布时间：2023-12-18 -
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