最新刊期
卷 ， 期 9 ， 2008
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- 摘要：A model based on the population dynamics method（PDM） was used to analyze the solidification behaviors of the Al-12Zn alloy droplets produced by gas atomization,and effects of the initial gas velocity and the melting temperature on the solidification process of single droplet were approached. The results show that the droplet undergoes five different thermal stages,i.e. liquid phase cooling,nucleation and recalescence,grain growth,eutectic solidification,solid phase cooling. The solid phase fraction in a droplet with a given size can be decreased with increasing in initial gas velocity or in melting temperature at the same flight distance.关键词：Spray Forming;Droplet;Solidification;Modeling;Atomization
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发布时间：2023-12-18 - 摘要：Effects of Al,Ti and Ta on microstructure and properties of Ni-based single crystal superalloy prepared by ISP-05-DS/SC furnace were investigated by testing both solvus temperature and mismatch degree . The results reveal that Al,Ti and Ta elements are mainly distributed in γ′ phase in as-cast microstructure. The solubility of Co,Cr and Mo in γ phase and solvus temperature as well as the enlargement of mismatch can be increased with increasing in Al,Ti and Ta content,which results in the morphology of γ′ phase changed from spherical to cubic structure. In addition,the enduring life of the superalloy at high temperature can be improved with the increase of Al,Ti and Ta content.关键词：Superalloy;Single Crystal;Solvus Temperature;Mismatch;Enduring Life
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发布时间：2023-12-18 - 摘要：Based on the established mathematical and physical model for calculating the three-dimensional electromagnetic field in soft-contact continuous casting mold,effects of exciting current density,varied at 2.2×106 A/m2 to 1.32×107 A/m2,on the distribution of magnetic induction intensity and electromagnetic forces in soft-contact mold were simulated. The results show that the magnetic induction intensity and electromagnetic force in the surface layer of molten steel or billet can be effectively increased in the beginning solidification region ,however,the heterogeneities of magnetic induction intensity and electromagnetic forces along the circumference direction are enhanced with the increase of exciting current intensity. The values of magnetic induction intensity and electromagnetic forces at slits are evidently higher than that at the segment center. Besides,change gradient of electromagnetic forces along height direction of mold is increased with increasing in exciting current density,resulting in the deterioration of homogeneity. So the exciting current density should be controlled at a accepted range to ensure the quality of billet.关键词：Electromagnetic Soft Contact Continuous Casting;Exciting Current Density;Magnetic Induction Intensity;Electromagnetic Forces
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发布时间：2023-12-18 -
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- 摘要：Ti-46Al-2Nb-2Cr alloy with coarse grain was prepared by induction skull melting with a non-consumable electrode. The effects of cooling rate on as-cast microstructure of alloy during pre-treated process at high temperature were observed by OM （optical microscope） and SEM （scanning electron microscope）in case of different quenching conditions . The results reveal that the cooling rate has obvious effect on microstructure of the alloy with coarse grain. High cooling rate can improve the refinement of grain in the alloy after heat treatment,strengthening refining effect and promoting the process of refinement,while low cooling rate can decrease the refining effects and restrain the refining velocity.关键词：TiAl Alloy;Heat Treatment;Cooling Rate;Microstructure;Grain Refinement
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发布时间：2023-12-18 - 摘要：Aiming at the expensive price of ZCAST powder produced from Z-corp,we have developed a mixed powder of plaster with 400 meshes and Al2O3 powder with 200 meshes whose mass ratio is four via six. The gear mould was printed successfully based on the self-developed mixed powder through rapid prototyping machine. The aluminum alloy gear was produced successfully with the baked and solidified mould by following the processing procedure of ZCAST technology,decreasing 50% cost of rapid prototyping materials.
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发布时间：2023-12-18 - 摘要：The strength of modified silicate sand was examined. The results reveal that sequence of initial strength value of silicate sand is as follows: modified resin silicate sand containing -CONH2 polarity higher than modified resin silicate sand containing -COONa polarity higher than common silicate sand higher than modified resin silicate sand containing HO-O-CH2OH polarity,while the increasing sequence of final strength value is as follows: modified resin silicate sand containing -COONa polarity more than modified resin silicate sand containing HO-O-CH2OH polarity more than modified resin silicate sand containing -CONH2 polarity more than common silicate sand under the condition of the same binder addition and blowing. Comprehensive properties of modified resin silicate sand containing -COONa polarity is acceptable. In addition,with increasing in blowing time,the initial strengths of all mold sands are increased while the final strengths are decreased gradually. With increasing in blowing volume,the initial strength is declined while final strength is increased.关键词：CO2 Hardening;Modification;Silicate Sand;Strength
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发布时间：2023-12-18 - 摘要：Microstructures of ingot and sintered Nd31Dy3Fe62.57Nb0.6Co1.2Cu0.3Al0.3B1.03 alloy with multi-element alloying were investigated,especially the distribution of micro-alloying elements in microstructure. There exists obvious radial segregation in the ingot,and dendritic α-Fe phase was found in the center of the ingots. Nb was distributed in the interface of Nd2Fe14B phase as Nb-Fe phase. Cu and Co element have obvious enrichment in the Nd-enriched phase,however,obvious enrichment of Al element in ingot was absent. There are similar regularities for elemental distribution in sintered magnets,however,the degree of elemental enrichment is slightly decreased,in which the grain boundary becomes more straightness after tempering treatment. The magnetic properties of sintered magnets were Br of 1.097T,Hcj of 1 092 kA/m,（BH）max of 220 kj/m3.关键词：Sintered NdFeB Magnets;As-cast Microstructure;Sintered Microstructure;Element Distribution
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发布时间：2023-12-18 - 摘要：Effects of different Al contents,including 0,1.68%,4.72% and 7.10%,on wear resistance of ZG40Cr25Ni20 steel were examined by metalloscope,X-ray diffraction （XRD）,scanning electron microscope （SEM） and wear resistant testing. The results show that Al content can improve the wear resistance of the steel,and the steel exhibits desirable wear resistance with 7.10% Al content,which is higher 2.62 times than that of the steel without Al at the same condition. Meanwhile,compared with that of one with 1.68% Al,the wear resistance of steel with 4.72% Al is increased by 66.40%. Wear mechanism of the experimental alloy is characterized by micro-cutting.关键词：Aluminum;Wear Resistance;Weight Loss;Wearing Mechanism
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发布时间：2023-12-18 -
- 摘要：A inner-outer compound cooling method that set a U shape cooling pipe in mould was employed for improving heat transferring efficiency in continuous casting Q2351 slab with 165mm in size. The filling process of liquid steel in mould with inner-outer compound cooling water was simulated by CFD software based on flow field coupling with temperature field. The simulated results show that inner-cooler can promote the solidification speed of continuous casting billet and decrease the flow-back velocity of poured liquid steel as a result of improving heat transferring efficiency,and the flow of liquid steel was homogenized to improve the quality of billet.关键词：Continuous Casting Slab;Inner Cooler;Flow Field and Temperature Field;Numerical Simulation
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发布时间：2023-12-18 - 摘要：The initial sketch for rudder horn steel castings in super-large oil tanker has been designed based on the technological experiences,which was conducted 3D moulding by the Solidwork software to get the STL document for Huazhu CAE. The temperature field in the steel castings during solidification process was simulated by the Huazhu CAE system to predict the potential shrinkage porosity （hole） defects. Based on above simulated results,the casting sketch was optimized. The results show that sequential solidification can be realized by rationally setting riser,chill iron and gating system,and the qualified rudder horn casting steel castings has been produced successfully.
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发布时间：2023-12-18 - 摘要：Hypereutectic Al-30Si alloy semi-solid slurry was prepared by low superheat pouring with weak intensity electromagnetic stirring. Effects of pouring temperature,stirring power and time on micro-hardness,wear resistance and thermal stability of samples were analyzed. The results indicate that compared with those of slurry prepared by conventional casting,comprehensive properties of Al-30Si slurry prepared by low superheat pouring with weak intensity electromagnetic stirring are obviously improved,and hardness is increased by 74.95 and wear resistance is increased by more than 10 times and thermal expansion coefficient is decreased by 22.16% in range of 20～300 ℃. The processing parameters influencing properties of semi-solid slurry samples are as follows: pouring temperature,stirring power and stirring time.
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发布时间：2023-12-18 - 摘要：Microstructural evolution of ZA84 magnesium alloy during semi-solid isothermal heat treatment has been observed by SEM （scanning electron microscope） and OM （optical microscope）. It is revealed that it is possible for preparing ZA84 magnesium alloy with non-dendrite structure by semi-solid isothermal heat treatment. After treated at 570 ℃ for 120 min,the non-dendrite structure with 22% liquid phase and un-melted primary solid phase with average size in 57 μm can be observed in the ZA84 alloy. Furthermore,the microstructural evolution of ZA84 magnesium alloy during semi-solid isothermal heat treatment exhibits coarse in beginning,then phase separation and shperoidization,and the final coarsening of spheriodized grain is absent.关键词：Magnesium Alloy;ZA84 Magnesium Alloy;Semi-solid;Semi-Solid Isothermal Heat Treatment
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发布时间：2023-12-18 - 摘要：Effects of SSS die casting processing parameters on properties of ADC12 aluminum alloy castings were examined by a standard tensile testing specimen with different ingate configurations. Microstructure of the alloy castings was observed by optical microscope （OM）,SEM（scanning electron microscope）,X-ray diffraction （XRD） and energy spectrum. The results reveal that densities of all SSS die castings are superior to that of conventional die castings. The larger the ingate cross section is,the more effects on properties of the casting is in process of SSS die casting. There exists a optimum ingate speed under a specific ingate configuration and size,and the optimum ingate speed in three kinds of ingate configuration are less than 0.6m/s. Desirable primary α phase and eutectic Si phase can be obtained at the optimum ingate speed.关键词：Die Casting;Ingate Speed;ADC12 Aluminum Alloy;SSS;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The shrinkage hole formed at oil sump by pouring liquid aluminum alloy from A direction,resulting in the leakage rate of the oil sump more than 20%. The position where shrinkage hole easily exist was determined by numerical simulation and product validation. Based on above analysis,the processing parameters and position of overflow tank were adjusted with adopting B direction pouring,eliminating obviously shrinkage hole defects and improving the quality of die castings.关键词：Filling Simulation;Die Castings;Shrinkage Hole;Leakage Rate
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发布时间：2023-12-18 - 摘要：Ceramic-salt core was developed for die casting piston with cooling gallery on the basis of common salt core,in which the ceramic additive,multipile granulation and new baking were adopted. And mould for ceramic-salt core as well as machining tools was considered. The ceramic-salt core is characterized by high strength （ 94.4 MPa）,high density （2.25 g/cm3） and low linear expansibility （42.8×10-6/℃ at 20～400 ℃）,meeting requirements of pressure and inner cooling gallery for piston.关键词：Salt Core;Die Casting;Ceramics;Piston
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发布时间：2023-12-18 - 摘要：Super-low carbon two phase stainless steel impeller body was produced successfully by ceramic mold investment casting combining with resin sand and sodium silicate sand casting. Eleven blades were cast by the whole casting mold,which can improve the dimensional precision,position precision and surface roughness of the impeller body. In addition,sound structure layer in impeller body surface can be reserved due to cutting-free,which improves the corrosion resistance,anti-pressure and wear resistance of the impeller body and increase the service life as well as shortening product period.关键词：Super-low Carbon Two Phase Stainless Steel;Impeller Body;Blades;Investment Casting
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发布时间：2023-12-18 - 摘要：Quality control of sol silicate shell mold in investment casting was described,including adhesive agent,coating additive and refractory. In addition,quality control of coating processing performance was introduced including fluidity,coverability,homogeneity and stability. Shell-making process was expounded to improve the quality of shell mold,such as proper proportion of coating,adjustment of coating processing performance,stuccoing,drying shell-mold,dewaxing and high temperature baking.关键词：Sol Silicate Shell Mold;Investment Castings;Raw Auxiliary;Quality Management
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发布时间：2023-12-18 - 摘要：The Euler/Lagrange model was established to simulate the fluidity of gas-solid phase in filling process of foam bead in lost foam casting. Meanwhile,the experiment of filing process was performed. The results show that the simulated results is well in agreement with experimental ones,confirming the availability of the model.关键词：Lost Foam Casting;Filling Process;Two Phase Flow;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Microstructure and mechanical properties of spray deposition-extrusion-rolling SiCP/FVS0612 composite sheet were investigated by XRD（X-ray diffraction）,OM （optical microscope） and TEM（transmission electron microscope）. The results reveal that tensile strength,yield strength and elongation of the prepared SiCP/FVS0612 composite sheet are 420 MPa,405 MPa,4.5%,respectively,at room temperature and 229 MPa,130 MPa and 3.5%,respectively,at 315 ℃ as well as 141 MPa,131 MPa and 3.3%,respectively,at 400 ℃,showing acceptable mechanical properties. In addition,the decrement of hardness of the composite sheet can be ignored with annealing at 400 ℃ for 200 h. Microstructural observation reveals that the desirable heat resistance is mainly attributed to the creation of fine spheroidal dispersive Al12（Fe,V）3Si phase in the composite sheet. In addition,SiC particle addition can play positive role for improvement of heat resistance of the composite sheet also.关键词：Spray Deposition;Heat Resistant Aluminum Alloy;Composites;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The microstructure and properties of Cr3C2/Cu composites prepared by vacuum arc furnace with graphite crucible insolating copper crucible were investigated by SEM （scanning electron microscope） and OM （optical microscope）. The results show that Cr can react with C in graphite crucible during melting to generate Cr3C2 particle distributed uniformly into the liquid Cu,and the Cr3C2 particle reinforced Cu matrix composites was prepared successfully. The micro-hardness,electric conductivity and softening temperature of composites are 184.8,45.76 MS/m and 540 ℃,respectively,showing desirable mechanical and electric properties.关键词：Cr3C2/Cu Composites;Electric Arc Furnace;Graphite Crucible;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：Al-Nd phase can be generated and the grain can be refined in the AZ91 magnesium alloy with Nd addition. The tensile strength at room temperature of the alloy can be improved due to Nd content affecting the type,morphology,size and distribution of Al-Nd phase. Acicular Al11Nd3 phase is major in the alloy with 1.0% Nd addition,and bulk Al2Nd phase is obviously increased with acicular Al11Nd3 phase reduction in the alloy with 2.0% Nd addition,and the Al2Nd particle phase is almost dominant in the one with 2.5% Nd addition. Compared with those of one with 1.0% Nd addition,the elongation,tensile strength and yield strength of the one with 2.0% Nd addition are increased by 33%,14% and 4%,respectively,and those of alloy with 2.5% Nd addition are increased by 44%,18% and 6%,respectively.关键词：Nd;AZ91 Alloy;Al-Nd Phase;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Effects of direct sintering and ball milling combined with sintering on Ti/Al ratio and forming temperature in fabricating high purity Al3Ti powder were analyzed with commercial Ti and Al powder,and possibility of refining grain size to nano-meter Al3Ti powder was approached. The results show that the forming temperature of Al3Ti particle can be decreased and very fine micron Al3Ti powder can be obtained by ball milling combining with sintering method,which is attributed to the decrease of reactive temperature and particle size resulting from refinement and desirable bonding of Al and Ti powder in processing of ball milling leading to the sharp refinement of nucleation phase and exposure of amounts of fresh surface as well as increasing in composition activation. The molar ratio of Ti/Al is equal to the theoretic values of 1∶3 in ball milling combining with sintering method,which is less than 1∶2.5 in direct sintering method. In addition,the absence of Ti nuclei in formed Al3Ti particles in ball milling combining with sintering can be observed,superior to that in direct sintering. The refinement of Al3Ti particles by mechanical ball milling reveals that the nano-Al3Ti particles can be successfully prepared by common equipment at proper atmosphere .关键词：Mechanical Milling;Reactive Sintering;Ti-Al Intermetallic Compound;Refinement
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发布时间：2023-12-18 - 摘要：Microstructure and constituent of in situ synthesized Mg-Al4C3 master alloy were analyzed with the help of DTA （differential thermal analysis）,XRD（X-ray diffraction）,SEM （scanning electron microscope） and EDS（energy dispersive spectrum） based on thermodynamics calculation. The results indicate that Mg-Al4C3 master alloy can be successfully synthesized by in-situ reaction at more than 700 ℃ for more than 1 h in Mg-Al-C system. In addition,formation mechanism of Al4C3 particle was expounded.关键词：Mg-Al4C3 Master Alloy;In-situ Synthesis;Mechanism
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发布时间：2023-12-18 -
Effects of Electrolyte Proportion on MAO（Micro-arc Oxidation） Ceramic Coating on ZAlSi12Cu2Mg1 Alloy
摘要：The formation of MAO ceramic coating on ZAlSi12Cu2Mg1 alloy was observed in electrolyte which is composed of NaSiO3,Na2WO4,NaOH,glycerin and Na2EDTA. Effects of different proportions on critical arc starting voltage,stable oxidation time,the forming rate and hardness of coating were analyzed. The results show that NaSiO3 and NaOH can evidently promote the formation of coating,and the Na2WO4 can improve the hardness of coating. Meanwhile,NaOH can decrease the critical arc-starting voltage,and glycerin and Na2EDTA can increase stable oxidation time and improve the stability of MAO. Microstructural observation reveal that the wear resistance of the ceramic coating can be evidently improved in glycerin and Na2EDTA electrolyte as a result of refining ceramic particle in coating and improving the bonding condition of coating and matrix alloy.关键词：Electrolyte Proportion;ZAlSi12Cu2Mg1;MAO;Ceramic Coating- 2
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发布时间：2023-12-18 - 摘要：Tilting casting,gating system and mould design of aluminum alloy air intake manifold were described. Aiming at shrinkage hole （porosity） defects which often exists in castings,processing sketch was rationally optimized. The aluminum alloy air intake manifold was manufactured successfully by tilted casting with ingate section of 1 500 mm2 and mould pre-heating at 200～250 ℃ and pouring at about 710 ℃ for 9.5 s,in which the shrinkage hole （porosity） was eliminated by adopting air-venting from core print and quickly cooling for the thick location as well as feeding,improving the casting quality.关键词：Aluminum Alloy;Air Intake Manifold;Tilting Casting;Air Venting;Wind Cooling
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发布时间：2023-12-18 - 摘要：The fine microstructure with uniform distribution,which is composed of α+η lamellar eutectoid and minor nano-ε dispersoids,of spray formed Zn-40Al-2Cu alloy can be observed by SEM （scanning electron microscope） and TEM.（transmission electron microscope） and XRD（X-ray diffraction）. The tensile strength,hardness and elongation of extruded and heat treated alloy have been improved as a result of elimination of holes during deposition process. Wear experiment indicates that the frictional coefficient of the alloy is decreased with the increase of loading and is increased with increasing in wear rate. The wear mechanism is characterized by abrasion at a lower loading while it is characterized by adhesion and smearing wear at a higher loading. Compared with that of conventional as-cast Zn-40Al-2Cu alloy,the wear resistance of spray formed alloy after extruding and heat treatment can be greatly improved.
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发布时间：2023-12-18 - 摘要：Bubbling and peeling in hot rolled Cu-0.1Fe-0.03P sheet and slag in cold rolled thin sheet were investigated by scanning electron microscope（SEM）,EDS,XRD and TEM.The results reveal that deoxidation of P in Cu-Fe-P alloy can enhance the hydrogen absorption effects in copper melt,resulting in the dispersive distribution of hydrogen in alloy and aggregating growth of formed gas hole in hot rolling process,which are responsible for the origination of bubble.Meanwhile,the hydrogen in the copper melt can improve the oxygen absorption tendency,resulting in the formation of Cu2O.The low plasticity of Cu2O phase in bubbling and low bonding with matrix result in the peeling and slag of cold rolled sheet as a result of fragmentation or little deformation in subsequent cold rolling process.关键词：Cu-0.1Fe-0.03P;Lead Frame;Cu2O;Mi-crostructure
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发布时间：2023-12-18 -
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