最新刊期
卷 ， 期 11 ， 2007
- 摘要：Effects of TiC particle on the as-cast microstructure,mechanical properties and solidification behavior of ZA84 magnesium alloy（Mg-8Zn-4Al-0.25Mn）have been investigated.The results indicate that 0.5%TiC particle addition can refine the microstructure in the alloy,and convert thd ternary phase in the microstructure from the coarse quasi-continuous net into fine discontinuous net with more dispersive distribution,however,it cannot result in the formation of new phase in the alloy.Inaddition,the 0.5%TiC particle addition can improve the mechanical properties,creep resistance and castability of the magnesium alloy,in which the improvement of castability is possible attributed to the adjustment of solidified temperature range with TiC addition.
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发布时间：2023-12-18 - 摘要：Mg-9.0Al-0.8Zn-0.15Mn magnesium alloy with different erbium contents was prepared by ingot metallurgy.The effects of erbium additions on the microstructure and mechanical properties have been investigated by means of X-ray diffraction,optical microscope,scanning electron microscope and tensile testing.The results reveal that the microstructures of the alloy with different erbium additions are mainly composed of α-Mg phase,Mg17Al12 phase and Al3Er.Meanwhile,the grain size can be refined from 57 μm to 21 μm.In addition,the ambient tensile properties of the alloy can be improved obviously as a result of the improvement of morphology and distribution of Mg17Al12 phase in the alloy.关键词：Magnesium Alloy;Erbium;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：We have developed a magnesium alloy twin-roller rolling-casting equipment to prepare AZ31 magnesium strip.The microstructure of twin-roller casting-rolling magnesium alloy strip was observed,and the effects of rolling temperature on the microstructure were examined.The results revealed that fine,uniform and spheroidal grain can be observed in the microstructure of twin-roller casting magnesium alloy strip,integrating with the features of both rapid-solidification and semi-solid state.The rolling temperature has greatly affected the microstructure of magnesium alloy strip.The desirable microstructure can be observed in the AZ31 magnesium alloy with rolling at 685 ℃.关键词：Magnesium Alloy;Twin-roll Casting;Microstructure
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发布时间：2023-12-18 - 摘要：The precipitates change of the extruded T5 treatment Mg-9Gd-4Y-0.6Zr alloy with tensioning at 300 ℃ and 350 ℃ was observed by transmission electron microscope（TEM）.The results indicate that the precipitates phase β’ in the alloy did not transform into new equilibrium phase with tensioning at 350 ℃ for 1 hours.In the process of tension at both 300 ℃ and 350 ℃,the precipitates phase β’in the alloy was changed from network structure into strip structure parallel to deformed orientation,which can reduce the deformation resistance.Meanwhile,the re-dissolution of solute atoms in precipitates into the magnesium matrix can result in the decrease of the volume fraction of precipitates.In addition,the cross slip was observed not at 300 ℃ but at 350 ℃.All of above reasons can be responsible for the decrease of strength and heat resistance of the alloy.关键词：Mg-Gd-Y-Zr Alloy;Heat Resistance;Tensile;Precipitates
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发布时间：2023-12-18 - 摘要：In-situ TiBw/Ti composites were fabricated by SHS-induction melting.The fluidity and filling of the composites were evaluated,respectively,by pouring ⊥ shape and wedge shape samples in investment casting.It was found that compared with that of matrix alloy,fluidity of the Ti matrix composites is decreased by 30%,and the thinnest wall-thickness of wedge samples is 0.30 m.The new method to characterizing the filling of Ti matrix composites was put forward.The filling ability of in-situ TiBw/Ti composites was calculated in range of 0.975 m to 2.46 m in the condition of free flow.关键词：In-situ;Ti Matrix Composites;Fluidity;Filling Ability
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发布时间：2023-12-18 - 摘要：The benzoxazines used for precoated sand were optimally synthesized at 95℃ for three hours by measuring its gel time and soften point.The results reveal that molten viscosity keeps about 0.5 Pa·s by measuring molten viscosity-gel time curves at 90 ℃.The relationship between temperature and gel time of the benzoxazines with and without accelerating agent was investigated.In addition,the DSC curves of benzoxazines were examined.It was found that there exists a apparent thermo-positive peak,and the cured degree of the pre-coated sand is more than 90% at 200 ℃.The gel time of the resin becomes slow with temperature more than 200 ℃.The soften and cured properties of synthesized benzoxazines can meet the preparing requirement of pre-coated sand.关键词：Benzoxazines;Pre-coated Sand;Viscosity;DSC
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发布时间：2023-12-18 - 摘要：The filling and solidification of motor plate with large dimension and uneven wall-thickness as well as complicated cavity were simulated by a CAE commercial software in permanent casting.The optimized design of gating system and riser system was conducted,and the filling of liquid metal was controlled by a special structure on the basis of simulated results,which can shorten the trial-mould period and improve the quality of the mould,reducing the casting cost.关键词：CAE;Numerical Simulation;Permanent Casting;Mould
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发布时间：2023-12-18 - 摘要：The service stress of Mg wheel with different transition radius between spokes and outer-ring was comparatively analyzed by FEM under the same service conditions.It was found that the maximum stress value appearing mainly on the transitional segments between spokes and outer-ring and stress concentration is decreased and the stress distribution becomes more uniform with the increase of transition radius,improving the reliability and safety coefficient of the Mg wheel.The results provided a reference to re-design of strength structure of Mg alloy wheel.关键词：Wheel;Radius;Stress Concentration;FEM Analysis
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发布时间：2023-12-18 - 摘要：For high energy beam plasma arc,the thermal stress can be formed in the deposition layers due to the alternate heating-cooling during moving deposition,which can result in the creation of hot crack as a result of high residual stress after cooling.It is important to investigate the effects of scanning rate of stress field during plasma powder deposition and cooling conditions on hot crack.The heat transferring in plasma powder deposition is simulated by the finite element method.The thermal stress field in plasma powder deposition has been calculated through varying scanning rate according to the features of superalloy.The results reveal that with increasing scanning rate,the peak value of thermal stress can be decreased and the stress field can be more uniformly distributed,leading to the lower residual stress after cooling.关键词：Plasma Powder Deposition Manufacturing;Scanning Rate;Finite Element Method;Thermal Stress Field
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发布时间：2023-12-18 - 摘要：Effects of low superheat pouring with a shearing field（LSPSF） on the grain size and morphology of primary Si in hypereutectic Al-20Si alloy have been observed.The results show that semi-solid Al-20Si alloy slurry and billets with excellent quality can be prepared by LSPSF.Primary Si with uniform distribution is converted from plate-like structure into polygonal bulk structure,obtaining obvious refinement.The LSPSF refining effects can be enhanced by P modification,however,the segregation of primary Si phase can be observed with lower pouring temperature.The refinement and spheroidization of primary Si in the Al-20Si alloy is attributed to enhancing heterogeneous nucleation and controlling the anisotropic growth of primary Si phase by LSPSF.关键词：Rheocasting;Hypereutectic Al Alloy;Al-20Si Alloy;Microstructure;Solidification
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发布时间：2023-12-18 - 摘要：The effects of processing parameters on the microstructure of semi-solid ZL101 Al alloy slurry prepared by ultrasonic vibration were investigated,and the formation mechanism of the microstructure was approached.The liquid ZL101 aluminum was poured into a special-made metal cup with ultrasonic vibration or holding for some times at 630660℃.The results indicate that the average grain size of α-Al phase is decreased to about 90μm with the average shape coefficient more than 0.5 with vibrating for 144s.The average shape coefficient of grain is firstly decreased then increased with holding for the vibrated semi-solid slurry.The finer and spheroidal grain in the microstructure can be observed with increasing the ratio of ultrasonic time to interval time in the other same condition.关键词：Ultrasonic Vibration;Aluminum Alloy;Semi-solid Metal;Slurry;Solidification Structure
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发布时间：2023-12-18 - 摘要：Spraying and releasing properties of three kinds of powder release agent were examined by dipping aluminum melt method,and the spraying parameters were optimized.The results revealed that the release agent exhibits excellent spraying and releasing properties when its compositions consist of 50% talcum powder,25% graphite,15%BN powder,10% additive and the rest.Aluminum-sticking would appears in all of steel plate immersed into liquid aluminum,in which the most serious surface aluminum-sticking can be observed with preheating steel plate at 230 ℃,while it is the most slight with preheating at 270℃.The optimized spraying effects can be obtained with preheating at 270 ℃ for 10 s.关键词：Die Casting;Aluminum Alloy;Powder Release Agent
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发布时间：2023-12-18 - 摘要：The basic principles of choosing die casting machine were introduced,including the alloy materials,shape dimension,quality,precision and inner quality of die castings,the power distribution during injection process as well as auxiliary parts,and so on.关键词：Die Casting Machine;Die Cast Alloy;Die Castings
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发布时间：2023-12-18 - 摘要：The design of mould structure of a conductive aluminum alloy castings in low pressure casting was described,and its processing parameters was determined also.Selection of parting face and adjustment of wall-thickness of the castings was taken into account in the mould design.Smooth filling and better feeding effects can be realized by using side-pouring gating system with double layer runner.The produced castings can meet requirements both in air tightness and in conductivity.关键词：Aluminum Alloy;Conductor;Low Pressure Casting;Mould Design;Processing Parameters
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发布时间：2023-12-18 - 摘要：Squeezing casting mould for the hammer head of hammer crusher was designed according to the structure of the hammer head and operating requirement combining with the features of high Mn steel.The special squeezing casting machine with maximum extruded force of 12 500 kN was adopted.Indirectional forming was adopted with horizontal mould-opening in the mould design,and butterfly spring and cylindrical spring were used to realize floating forming to fully utilize the ability of locking cylinder.In addition,the squeezing castings were pulled out by up-moving of bottom cylinder.关键词：Mould Design;Squeezing Casting;Hammer Head;Hammer Crusher
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发布时间：2023-12-18 - 摘要：The shell mold made of the investment powder has the features of high strength and good collapsibility as well as non-crack in baking,and the investment castings produced with the mold shell exhibit high dimensional accuracy,excellent surface roughness and reproduction with absence of defects,so the investment powder can be taken as the molding materials for jewelries,art crafts,watches,plane and military as well as superalloy,such as Ni,Cr,Pt,Yr,Pa.The types,application and market of the investment powder were described,especially the present status at home and aboard,and its future was predicted also.关键词：Noble Metal;Investmetn Casting;Investment Powder;Quartz
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发布时间：2023-12-18 - 摘要：Ni-Cu M-35-1/Monel alloy in investment casting can not pass the examination of gas pressure due to low compactness of microstructure resulting from the generation of CuO inclusion in grain,which is attributed to long time Cu smelting at high temperature resulting in the serious oxidation due to the high difference of melt point between Ni and Cu.Through adjusting material-adding sequence and deoxidized method,increasing deoxidized time to fully ensure deoxidization as well as shortening oxidized time of Cu at high temperature to reduce the oxidation of Cu,the problems can be effectively eliminated.The investment castings can totally meet the requirement by quality check with qualified rate more than 97% of gas pressure examination.关键词：Investment Casting;Ni-Cu Alloy;Smelting
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发布时间：2023-12-18 - 摘要：The surface crack in TP2 copper tube billets in horizontal continuous casting was analyzed by spectral analysis,oxygen content analysis and scanning electron microscope.The results reveal that hot crack is mainly located in the upper of the tube billet,distributing along the circumference of the tube billets and propagating along the grain boundary.In addition,the crack fracture with 515 mm in length and 0.11.5mm in depth is seriously oxidized with the oxygen content of 3.15%.The crack can be effectively eliminated by controlling the pressure and flow volume of cooling water as well as increasing drawing speed.关键词：TP2 Copper Tube;Horizontal Continuous Casting;Surface Crack
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发布时间：2023-12-18 - 摘要：Improvement of horizontal continuous casting was performed to produce the Sn-Zn alloy ingot according to the characteristics of Sn-Zn alloy.The improved technical ways were conducted by analyzing origination of billet-broken and internal crack from the viewpoint of alloy composition.The Sn-Zn alloy billets with excellent and stable quality can be produced by modifying mould structure,strengthening cooling rate and improving drawing mechanism as well as controlling liquid head,and adopting the rapeseed oil as lubricant.The main technical parameters of pulling machine and holding furnace were provided.关键词：Sn-Zn Alloy;Horizontal Continuous Casting;Improvement
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发布时间：2023-12-18 -
- 摘要：The filling morphology of gray cast iron melt in lost foam casting was observed by rapid photography method.The results indicate that the vacuum degree has the significant effects on the filling morphology and filling velocity of gray cast iron melt.With the increase of vacuum degree,the wall attachment effects of filling molten metal would be more apparent and the filling time would be shortened greatly,verifying the basic principle of the molten metal filling.关键词：Lost Foam Casting;Grey Cast Iron;Filling Morphology;Filling Velocity
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发布时间：2023-12-18 -
Influence of Heavy Gravity on In-situ Al2O3/ZrO2 Composite Ceramics Prepared by Combustion Synthesis
摘要：In-situ Al2O3/ZrO2（4Y） composite ceramics was prepared through combustion synthesis under heavy gravity with adding ZrO2（4Y） powders into the thermit.XRD analysis and SEM images reveal that the ceramic matrix is mainly composed of random-oriented rod-like eutectic colonies,on which triangular dispersion of orderly submicron t-ZrO2 is embedded,surrounded by thin boundary regions made up of Al2O3crystals and ZrO2 grains.Compared to the in-situ Al2O3/ZrO2（4Y） composite ceramics prepared by combustion synthesis under gravity,the separation of liquid metal/ceramic melt/gas can be greatly accelerated,and the constituent in ceramic melt can be more homogenized due to the increase of combustion process and velocity as well as enhancing the velocity of mass transportation under heavy gravity,which results in the great improvement of the compactness,reaching 98.3% in ceramic relative density,and the generation of finer and more clean and homogeneous microstructure in the ceramic matrix,reaching 96.8% in volume fraction of Al2O3/ZrO2（4Y） eutectic colonies.Therefore,mechanical properties of the Al2O3/ZrO2（4Y） composite ceramics under heavy gravity can be improved remarkably,increasing by 37.2%,56.4% and 69.1% in the Vickers hardness,in fracture toughness and in bending strength,respectively.关键词：In-situ Al2O3/ZrO2（4Y） Composite Ceramics;Combustion Synthesis;Heavy Gravity;Eutectic Growth;Mechanical Properties- 2
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发布时间：2023-12-18 - 摘要：Al2O3/Cu composites were prepared by internal oxidation with Cu2O oxidizer.The electric erosion behaviors of the composites were tested by electric sparking,and its microstructure was observed also.It was found that nano-Al2O3 particle is dispersively distributed into the Cu matrix of the internal oxidized prepared Al2O3/Cu composites.The tool-electrode wear rate and surface roughness of Al2O3/Cu composites are evidently superior to that of red copper in the condition of the same machining speeds,and they is decreased with the increase of Al2O3 particle content.关键词：Internal Oxidation;Al2O3/Cu Composites;Electric Erosion;EDM
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发布时间：2023-12-18 - 摘要：The dynamic compressive stress via strain response characteristics and effects of different rolling routes on it have been analyzed by conducting the dynamic compressive experiment on Al/Mg laminated composites prepared by compound rolling with the Hopkinson bar.The results reveal that stress via strain behavior of the Al/Mg laminated composites exhibits evidently the strain rate hardening effects and the dynamic hot softening effects with the strain rate in range of about 103s-1.With increasing the rolling reduction rate,the flow stress of the composites can be decreased.The rolling temperature has the important effects on σ-ε curves of the Al/Mg laminated composites while it has little affected the flow stress.The flow stress of rolled Al/Mg laminated composites can be decreased with annealing at 300 ℃ for 1 hours.The fracture morphology of the magnesium alloy is characterized by cleavage fracture with dimple rupture tearing ridge resulting from the hot softening effect,while the fracture morphology of the aluminum alloy is characterized by intergranular brittle crack with the rupture of intercrystalline compound.关键词：Al/Mg Laminated Composites;Rolling;Dynamic Compression;Strain Rate
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发布时间：2023-12-18 - 摘要：The effects of extruding treatment on microstructure and properties of CuCr30 contact composites prepared by combustion synthesis-casting have been investigated.The results indicate that the extruding treatment can not only refine the grain size in the composites,but also improve the electric conductivity,density and hardness.So it is a desirable approach to improving the microstructure and properties of the composites by extruding treatment.关键词：Extrusion;Combustion Synthesis;Cu-Cr Contact Composites;Densification;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：Effects of Sn on GFA and magnetic performance of Fe-Ni-Al-Ga-P-B-C-Si series amorphous alloy have been examined by XRD（X-ray diffraction）.The results show that as-cast Fe68-xNi1Al5Ga2P9.65B4.6Si3Snx（x=0,0.5,1.5,2.5） alloy is amorphous alloy,and the brittleness of the alloy is sharply deteriorated with the increase of Sn content.DSC analysis reveals that with increasing Sn content,the glass transition temperature of alloy Tg is gradually declined and under-cooling liquid zone is gradually widened with more and more amplitude increase.First crystallized exothermal peak Tp1 is blurred with 0.5% and 1.5% Sn content,which shows that the alloy is changed from secondary crystallization to primary crystallization.The alloy containing 2.5% Sn has better soft magnetic property.关键词：Fe-based Amorphous Alloy;Alloying Elements;Glass Forming Ability;Thermal Stability;Magnetic Performance
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发布时间：2023-12-18 - 摘要：The Al-Ti-B master alloys with and without TiH2 have been prepared by SHS（high-temperature synthesis） with inducing by laser.The phase constituent,distribution,microstructure morphologies of master alloys and its thermal reaction were analyzed by XRD,EPM,DTA and SEM.The results reveal that the TiH2 addition has a positive role for promoting the reaction synthesis of the Al-Ti-B master alloy,which is attributed to high active Ti atoms and catalyzing H atom released by TiH2 thermal decomposition reducing the reaction temperature and changing the morphologies and distribution of TiAl3 and TiB2 particles（the average diameters of the TiB2 particles lower than 0.5 μm） to relief the segregation of TiB2.The refining effects of the Al-Ti-B master alloy with TiH2 on industrial pure aluminum is superior to that of ones without TiH2 due to its structure and morphology more suitable for refining treatment.关键词：Laser;TiH2;SHS;Al-Ti-B Master Alloy
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发布时间：2023-12-18 - 摘要：Fe can seriously deteriorate the mechanical properties of as-cast Al-Si alloy due to its needle-like morphology in microstructure of the alloy.The effects of various Sr content,such as 0.03%,0.06%,0.09%,0.12% and 0.18% addition,on the microstructure and mechanical properties of ZL102 alloy containing 1.2Fe have been described.It was found that the coarse needle-like iron phase begins to present the phenomena of broken and dissolution with the addition of the Sr.Meanwhile,the lengths of the needle-like iron phase can be decreased with the increase of Sr addition.However,the iron phase morphology can only be slightly changed by Sr element.Both tensile strength and elongation of the alloy show the tendency of first rise and then drops with Sr content increase.The optimized mechanical properties can be obtained with 1.2% Sr addition.关键词：Al-Si Alloy;Iron Phase;Sr
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发布时间：2023-12-18 - 摘要：Effects of 012.0 g/L（NaPO3）6 in a Na2SiO3 electrolyte solution on the thickness,porosity on the surface of ZAlSi12Cu2Mg1 rate and phase constituent of ceramic coatings prepared by MAO have been observed.The results indicate that with increasing the（NaPO3）6 content from 0 to 12 g/L,the thickness of MAO coatings is increased gradually,and the porosity rate is decreased with（NaPO3）6 content increasing from 0 to 6.0 g/L while it is increased with（NaPO3）6 content more than 6.0 g/L.XRD analysis reveals that the ceramic coating oxidized in the electrolyte solution without（NaPO3）6 is composed of γ-Al2O3,α-Al2O3 and Al2SiO5,in which the intensity ofα-Al2O3 is equal toγ-Al2O3,while oxidized in the electrolyte solution with 6.0 g/L（NaPO3）6,it is no found that there exists Na+ or PO3-in the coatings,however,the intensity of α-Al2O3 is more than γ-Al2O3 distinctly,and the intensity of Al substrate is slightly decreased.关键词：Electrolyte Solution;(NaPO3)6;ZAlSi12Cu2Mg1;MAO（Micro-arc Oxidation）
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发布时间：2023-12-18 - 摘要：Uniform fine microstructure in the spraying deposition forming high Al-Zn alloy with absence of segregation is observed by SEM and TEM.XRD analysis reveals that the microstructure of alloy is composed of Zn-Al eutectoid structure and nano-scale dispersed precipitation.In addition,many non-regular and uneven distributed pores are created in the alloy during spraying deposition,resulting in the compactness of about 90%.关键词：Spraying Deposition;ZA Alloy;Refinement;Eutectoid Structure;Pores
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发布时间：2023-12-18 - 摘要：Serious pollution of smelting Mn-Cu damping alloy in conventional melting method is solved by a combination method,and the Mn-Cu damping alloy with stable chemical composition and excellent properties was fabricated.The sketch of secondary smelting damping alloy in furnace for steel was put forward based on new smelting principle.关键词：Damping Alloy;Combination Smelting;Secondary Smelting
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发布时间：2023-12-18 -
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