最新刊期
卷 29 ， 期 8 ， 2009
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- 摘要：3D-C/Cu composites were synthesized successfully by molten infiltration of Cu-6Ti alloy into fine weave pierced fabrics of carbon fiber,and microstructure and interfacial characteristics of the composites were analyzed by X-ray diffraction （XRD）,optical microscope（OM）,scanning electron microscope （SEM） and energy dispersive spectrometry （EDS）. The results indicate that the wettability of copper matrix with carbon fiber can be obviously improved with proper Ti addition,which is beneficial for the molten infiltration effects.Molten alloy is infiltrated into carbon fiber fabric due to pressure difference during molten infiltration. Desirable infiltration effects can be observed by microstructural analysis. The interface of composites is formed by diffraction reaction of Ti with C,and its thickness is increased with advancing in diffraction. Finally,fifty-four minutes later,the reactive diffusion is completed.关键词：C/Cu Composites;Carbon Fiber;Fine Wear Pierced Fabric;Molten Infiltration
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发布时间：2023-12-18 - 摘要：Microstructure and solidification behavior of inducing melted Cu83Fe17 alloys and melt spun Cu83Fe17 alloys were investigated by scanning electron microscope （SEM）. The results show that microstructure consists of fine primary Fe-rich dendrite existed in Cu-rich matrix in vacuum inducing melted Cu83Fe17 alloy,while both Fe-rich dendrites and Fe-rich spheroids appear in microstructure of melt-spun Cu83Fe17 alloy. The morphology and size of the Fe-rich phase are varied greatly with the change of ribbon thickness. The diameter of Fe-rich spheroids nearby surface-free is more than that nearby contacted surface,exhibiting non-uniform distribution,which is attributed to the appearance of metastable liquid phase separation during rapid solidification. In addition,the cooling rate for Cu83Fe17 alloy was calculated by one-dimensional heat conduction equation,and cooling rate of 1.5×106 K/s can be obtained at surface-free of the alloy ribbons with 200 μm in thickness.关键词：Cu83Fe17 Alloy;Cooling Rate;Microstructure;Liquid Phase Separation
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发布时间：2023-12-18 - 摘要：Surface replication behavior of Mg65Cu25Y7Nd3 bulk amorphous alloy in the super-cooled liquid region was examined by using two different Al-Si binary alloys as the parent surface to form the subtle morphology in the surface of bulk amorphous alloy. The results show that surface with complex morphology can be well replicated in the super-cooled liquid region of Mg65Cu25Y7Nd3 bulk amorphous alloy under a load much lower than those applied in other works.关键词：Bulk Amorphous Alloy;Replication Behavior;Super-cooled Liquid Alloy
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发布时间：2023-12-18 - 摘要：The superplasticity of as-extruded magnesium alloy was examined with strain rate of 10-210-4s-1 at 400440℃. The results reveal that necking contract is dominant in tensile fracture of the specimens with a higher strain rate. With increasing in temperature,m value （strain rate sensitivity index） and elongation of the alloy are increased. With a lower strain rate,tensile fracture mechanism is controlled by cavity expansion,resulting in the decrease of elongation with increasing in temperature. Superplasticity deformation mechanism map was drawn by analyzing deforming mechanism. The results indicate that,with a low strain rate,at 400℃ or 420℃,deformation mechanism is characterized by dislocation creep controlled by the solute drag,while with a higher strain rate,it is characterized by the dislocation creep controlled by climb. At 440℃,deformation mechanism of the as-extruded alloy is accordant with the dislocation creep controlled by lattice diffusion.关键词：AZ31 Magnesium Alloy;Superplasticity;Deformation Mechanism Map
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发布时间：2023-12-18 - 摘要：As-cast microstructure features of Al sheet for manufacturing a pressure can with high formability prepared by different melt-treatment technology were observed by SEM （scanning electron microscope）,EDAX,TEM （transmission electron microscope） and SAED （selected area electron diffraction）. The results reveal that oxide inclusions in the Al sheet are mainly γ-Al2O3 phase,and Fe-rich impurity phases in the Al sheet are mainly Al3Fe,T1（Al12Fe3Si） and AlFeSiRE phase,in which AlFeSiRE phase exhibits complicated non-determined structure. Melt-treatment technologies exhibit remarkable effects on microstructure of as-cast aluminum sheet. There exists much oxide inclusion with large size approximately 1040 μm in diameters,non-uniform distribution is gathered together in the large block form,and Al3Fe phase,and T1 phase as well as a little metastable phase Al6Fe phase exhibits coarse acicular structure or skeleton structure in the conventional treatment or treated-free aluminum sheet,furthermore,the oxide inclusion is easy to aggregate with Fe-rich phases. While in high efficiency melt-treatment aluminum sheet,there exists a little oxide inclusion with uniformly dispersive distribution and fine size less than 4μm,and Re-rich phases are mainly AlFeSiRE phase and little Al3Fe phase,in which AlFeSiRE phase exhibits fine spheroidal structure with size less than 0.5μm or short rod structure distributing along grain. In addition,the absence of phenomenon of Fe-rich phases gathering together with oxide inclusions can be observed.关键词：Al Sheet for Can Manufacturing;Melt-treatment;Microstructure;Oxide Inclusion;Fe-rich Impurity Phases
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发布时间：2023-12-18 - 摘要：Effects of Mg-50 Al4Ce3 master alloy and Ce on the microstructural refinement of AZ31B magnesium alloy were observed by SEM （scanning electron microscope）,EDS （energy dispersive spectrum） and XRD （X-ray diffraction）. The results reveal that dendrite and grain size in AZ31B magnesium alloy can be remarkably refined with 0.5% Al4Ce3,and it is further refined with 0.5% Al4Ce3 and 0.3% Ce mixed addition,in which average grain size of α-Mg is decreased from 280μm in matrix alloy to approximately 50μm,and β phase is converted from continuous network structure into discontinuous network structure and fine particle with generation of Al4Ce phase. Based on the analysis of EDS and calculation of the planar mismatch between Al4Ce3 anf Mg,Al4Ce3 particles can be acted as the heterogeneous nuclei of primary α-Mg phase. Ce can result in the increase of constitutional undercooling of alloy,which can activate potential Al4Ce3 to form nucleation at solid-liquid interface front to increase the nucleation rate.
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发布时间：2023-12-18 - 摘要：Statistic features of the parameters were obtained by analyzing meso-structure of the semi-solid materials. Meso-structure model exhibiting statistics was established for semi-solid Al-4Cu-Mg alloy with heating at 540℃.Macro-mechanical response of the semi-solid alloy was calculated by the finite element method based on the model. The calculated results show that the rheo-behavior of the semi-solid materials is well in agreement with actual one,meanwhile,the calculated value is accordant with the measured one in the range of error except.关键词：Semi-solid;Meso-structure;Micro-mechanical Properties;Mechanical Response
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发布时间：2023-12-18 - 摘要：Two-dimensional transient FEM （finite element model） for heat transfer and elastic-plastic stress of liquid steel solidification in continuous casting round mould was established based on the ANSYS software,in which from the essential phenomena in the mould,a gas gap-dependent heat transfer condition were introduced to modify the heat flux function,and the variation of material thermal properties,mechanical properties as well as yield function with temperature were considered. Based on secondary development for the model,using multi-field indirect coupled method,the solidification shrinkage process of four kinds of round steel billets were simulated. The results reveal that solidifications shrinkage is closely related to steel types,carbon content and drawing velocity. Mould taper exhibits continuous parabolic curves along the height of the mould. At the outlet of mould,the solidification shrinkage rates of four round billets make 2.2 mm,3.41mm,3.79 mm and 4.30 mm,respectively. Based on the solidification shrinkage curves of round billets and basic principle of mould design,the universal parabolic taper for round mould is completed.关键词：Mould for Round Billets;Parabolic Taper;Solidifications Shrinkage;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Morphology of primary α-Al dendrite and eutectoids as well as primary θ phase and size variation,and formation mechanism of semi-solid casting Al-Cu alloy containing 10% Cu,20% Cu and 40% Cu were investigated by SEM （scanning electron microscope）,OM （optical microscope）. The results reveal that primary α-Al phase with size of 5080 μm exhibits near-equiaxed globular structure or rosette in semi-solid Al-10Cu and Al-20Cu alloy,while primary CuAl2 phase in semi-solid Al-40Cu alloy is fully converted from coarse long ribbon into particle or short rod with small length-diameter ratio or near-equiaxed particle with the average size lower than 80 μm,greatly improving the grain morphology. Compared with that by conventional casting,the microstructure of semi-solid casting Al-Cu alloy is significantly improved,fully meeting the demands of engineering application. Primary α-Al phase exhibits in-situ growth in semi-solid Al-Cu alloy in the condition of intensely stirring,which is responsible for the formation of near-equiaxed globular structure or rosette structure or small short rod and near-equaixed particle.关键词：Semi-solid Casting;Al-Cu Alloy;Microstructure;Formation Mechanism
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发布时间：2023-12-18 - 摘要：Microstructural evolution of the non-dendrite A357 aluminum alloy billets heated by the multi-workstation rotating electromagnetic induction was analyzed including quantitative metallographic observation and theoretical model calculation. The results reveal that there exist two stages in the microsrtuctural evolution of the primary α-Al phase in the alloy billets during electromagnetic induction heating with 75kW. The first stage,with heating time from 0 to 303 seconds,eutectic structure is melted and grain is grown by emerging,meanwhile,the average diameter of grain is increased;the second stage,the primary α-Al phase is refined accompanying with spheroidization. The average grain diameters in the billets are 87.8 μm on the top,85μm in the middle and 84.9 μm at the bottom with shaping factors of 1.37,1.44 and 1.40,respectively. Growth of α-Al phase is characterized by the Ostwald growth mechanism. Based on the Ostwald ripening theory,the growth exponent of 2.22.7 can be calculated. According to the calculated result,the average grain diameter in A356 aluminum alloy billets can be controlled to 66.3μm after electromagnetic induction heating.关键词：Semi-solid;Electromagnetic Induction Heating;Ostwald Ripening;Microstructural Evolution
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发布时间：2023-12-18 - 摘要：Semi-solid AZ91 Mg alloy slurry and A356 aluminum alloy slurry were prepared by mechanical stirring,which was used to produce Mg alloy rod and Al alloy billets for extruding double-layer metal tube by special billet-making-mould with a fixed size. Effects of processing parameters and reheating temperature as well as hold time on microstructure of semi-solid billets were observed to understand the thixo-forming behavior of two kinds of billets. The results reveal that it is beneficial to the formation of spheroidized structure in semi-solid when AZ91 magnesium alloy with 24 mm in diameters is reheated at 560℃ for 21 min and A356 ring billets with 8 mm in wall thickness is reheated at 600 ℃ for 20 min.关键词：A356 Aluminum Alloy;AZ91 Magnesium Alloy;Reheating;Thixo-forming
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发布时间：2023-12-18 - 摘要：Based on analysis of the physical change and geometric relation between the core and component,three calculating models and equations are presented. And relationship between the core-pulling forces and processing parameters are revealed,such as temperature of pulling core,the yield stress and critical shearing stress of component and protective coating,surface roughness. Practical production verifies that the method is available for engineering application.关键词：Squeezing Casting;Core-pulling Force;High Melting Point Alloy;Protective Coating
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发布时间：2023-12-18 - 摘要：The microstructure of joint in TIG welded die casting AM60B magnesium alloy plates was observed. The results indicate that the fusion zone （FZ） consists of uniform fine equiaxed grain and network high density eutectic Mg17Al12 phase distributed along grain boundary,and there exist small spherical gas holes distributed nearby surface. Gas hole with different sizes and shrinkage porosity can be observed in the partially melted zone （PMZ） nearby the FZ,and microstructure is composed of coarse equiaxed grain and decreasingly Mg17Al12 eutectic phase with worm or particle shape along grain boundary. The microstructure of PMZ nearby the heat-affected zone（HAZ） exhibits coarse structure and the disappearance of grain boundary with Mg17Al12 eutectic phase. In addition,microstructure of HAZ is similar to that of matrix materials,however,the coarseness of grain size can be presented.关键词：Die Casting;AM60B Magnesium Alloy;TIG Welding;Microstructure
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发布时间：2023-12-18 - 摘要：Factors influencing precision of selected laser sintered parts were analyzed based on theory and experiment,especially laser sintering parameters and sintering temperature. A set of processing parameters influencing size precision of metal powder were optimized through setting parts size as optimized target using 316 stainless steel as follows: laser power of 83W,scanning velocity of 16 mm/s,scanning spacing of 1/6 mm,thickness of sintering layer of 0.1 mm. Using these optimized sintering parameters,the precision of the part can reach ±0.05 mm,and metal prototype parts were fabricated successfully.
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发布时间：2023-12-18 - 摘要：By means of cavity effects of ultrasonic,acid washing passivation solution can generate a bundle of dense explosion on surface of the castings at pulling force of ultrasonic wave beam,which can activate the acid washing passivation process,resulting in not only passivating casting but also making surface of castings more smooth and delicious. The activation of acid-washing-passivating solution can greatly decrease acid-consumption rate and proportion as well as viscosity,which results in easy recovery and full utilization of resource,decreasing the product cost. In addition,waste castings resulting from over-corrosion during acid washing process was eliminated,and acid-fog was also relieved to some extent.关键词：Ultrasonic;Acid-washing-passive Solution;Acid Volume
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发布时间：2023-12-18 - 摘要：Effects of electromagnetic vibration from static magnetic and alternative current on solidification structure of horizontal continuous casting pure Sn thin ribbon and Sn-10Pb thin ribbon were analyzed by thermal-physical experiment. The results reveal that with electromagnetic vibration,solidification structure of pure Sn is greatly refined,which is refiner with increasing in current intensity. By applying electromagnetic vibration on solidification front of Sn-10Pb alloy,creation of equiaxed grain zone in the center of thin-ribbon can be distinctly accelerated,which is enlarged with increasing in electromagnetic intensity. Electromagnetic vibration forces can increase the nucleation rates through cracking and flaking primary phase as a result of periodical mechanical effects,such as tension,compression,shearing,bending and torturing,meanwhile,magnetic vibration can restrain the growth of columnar grain by decreasing gradient as a result of the homogeneous tendency of temperature and solute at solidification front of solid-liquid interface by partial stirring,which are responsible for the refinement and equiaxed grain formation of structure in condition of low intensity electromagnetic vibration.关键词：Thin Ribbon;Horizontal Continuous Casting;Electromagnetic Vibration;Solidification
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发布时间：2023-12-18 - 摘要：Effects of rolling-after-extrusion and rolling-after-hot pressing on microstructure and mechanical properties of mullti-layer spray-deposited SiCP/Al-Fe-V-Si composites were comparatively analyzed by OM （optical microscope）,SEM（scanning electron microscope） and TEM （transmission electron microscope）. The results indicate that,compared with rolling-after-extrusion ones,the rolling-after-hot pressing composites exhibit more uniform microstructure and more excellent mechanical properties. Ambient tensile strength and elongation of the sheet produced by rolling-after-hot pressing reach 620MPa and 9%,respectively. SiC particle lamination during extrusion can be eliminated by hot pressing densification to ensure the uniform and fine distribution of microstructure due to the desirable bonding between SiC particle and matrix alloy,which is responsible for the excellent mechanical properties of the composites sheet.关键词：Heat Resistant Alloy;Composites;Spray-deposition;Hot Working;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Magnesium alloy matrix composites （MMCs） with volumetric fraction of 15%,20%,25% and 30% were prepared with the preform made of crystallized aluminum silicate short fibers as reinforcement and aluminum phosphate as binder by squeezing casting at high temperature. Dry sliding wear properties of the composites were tested by using MM200 wear tester （block-on-ring configuration） against a hardened alloy steel counterface with hardness of 53HRC under loads of 10,20,30,40 and 50N and sliding velocities of 0.47 and 0.92 m/s,and wear morphology of the specimens was observed by SEM （scanning electron microscope）. The results reveal that effects of sliding speed on wear rate of the composites are higher and more complex than on those of the AZ91D matrix alloy,which is closely related to not only volumetric fraction in the composites but also applied loads.关键词：Aluminum Silicate Fiber;AZ91D Magnesium Alloy;Magnesium Matrix Composites;Sliding Speed;Wear Rate
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发布时间：2023-12-18 - 摘要：High vanadium high speed steel/carbon steel compound hammerhead was produced by liquid-solid bimetal compound method,and effects of different treatment conditions on compound role of hammer handle were described. The results indicate that fully metallurgical bonding in hammer handle treated by acid washing can be observed,exhibiting desirable compound effects,while it can not be observed in the hammer handle treated by mechanical rust-removal or treated-free. Hardness of high vanadium high speed steel /carbon steel hammer head treated by acid washing can fully meet the requirements,showing desirable working performance.关键词：Bimetal Compound;High Vanadium High Speed Steel;Compound Hammerhead;Metallurgical Bonding
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发布时间：2023-12-18 - 摘要：Effects of ultrasonic vibration on morphology evolution of solid-liquid interface of SCN-5% ethanol model alloy were observed during directional solidification. The results show that the growth of interface morphology of the model alloy can be restrained as a result of ultrasonic field restricting solidified velocity during directional solidification. Grain size in the alloy can be refined with applying-unloading ultrasonic field resulting from the increase of interface tip. In addition,ultrasonic field can increase nucleation rate as a result of creation and growth of bubbles to merging and collapsing,resulting in the refinement of grain size in the model alloy.关键词：Ultrasonic Vibration;Solidification;Model Alloy;Real-time Observation
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发布时间：2023-12-18 - 摘要：Peritectic reaction temperatures of Al-Ni alloys and Sn-Sb alloys were measured by DSC. With a given cooling rate,peritectic reaction temperature of Al-Ni alloys is serious delayed,while that of Sn-Sb alloys is nearly equal with equilibrium reaction temperatures,which is closely related to the structural difference of primary phase and peritectic phase. With different structure between primary phase and peritectic phase,peritectic reaction is seriously delayed,while with the same structure,the reactive temperature is identical with equilibrium temperature.关键词：DSC;Al-Ni Alloy;Sn-Sb Alloy;Peritectic Reaction;Crystal Structure
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发布时间：2023-12-18 - 摘要：The relationship between the viscosity of Al84Mg10Ce6 alloy melt and temperature was analyzed by viscosity measurements,X-ray diffraction and DSC analysis. Through observing the glass forming ability of the alloy ribbon,the relationship between different over-heating temperature and its glass forming ability of alloy melt was described. The results show that the element Ce addition results in the abnormal change of Al84Mg10Ce6 alloy melt structure,enhancing the glass forming ability of Al-based alloy. GFA of Al-Mg series alloys exhibits the relation with melt temperature,where amorphous Al ribbon can be prepared by melt-spinning technology at 850 ℃.关键词：Melt;Viscosity;GFA;Temperature
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发布时间：2023-12-18 - 摘要：Aiming at the clinical requirements for medical titanium alloy and its existing problems,a new kind of oral Ti-Zr-（M） titanium alloy was designed through adding Mo,Sn,La into Ti-Zr alloy system. Effects of heat treatment on phase constituent,microstructure and mechanical properties of the alloy were investigated by DX2000-X-ray diffractive instrument,4XC upside-down metallography,HV-50A sclerometer and M-200 abrasive machine. The results indicate that hardness of the annealed alloy is slightly decreased with the great improvement of wear resistance,which is attributed to Sn and La stablizing α phase and plays a role in solid solution strengthening effects and Mo being beneficial to the formation of β phase,meeting the requirements of biologic compatibility and wear resistance for oral Ti alloy materials.关键词：Ti Alloy;Annealing;Microstructure;Hardness;Wear Resistance
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发布时间：2023-12-18 - 摘要：Effects of SiC content on microstructure of AZ91D magnesium alloy were observed with adding varied Mg-SiC powder at different temperature by OM （optical microscope） and SEM （scanning electron microscope）as well as EPMA. The grain with size of 75 μm in the AZ91D magnesium alloy can be presented with 0.20% SiC addition at 760780 ℃. The results reveal that the grain size in the AZ91D magnesium alloy is remarkably reduced with Mg-SiC mixed powder,which is attributed to the creation of a little Al4C3 phase as the nuclei of α-Mg phase due to the reaction of Mg-SiC mixed powder and SiC as heterogeneous nuclei of α-Mg phase. Mg-SiC mixed powder is a desirable grain refiner for the AZ91D magnesium alloy.关键词：Magnesium Alloy;Mg-SiC Mixed Powder;Al4C3;Grain Refinement
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发布时间：2023-12-18 - 摘要：Al-Mg binary was made by conventional pressing-and-sintering techniques,and its forming parameters were approached based on single variable method. The desirable Al-Mg alloy containing 5% Mg can be successfully prepared with 300MPa pressure at 600℃ sintering temperature,whose relative density reaches 95%. Based on above mentioned processing parameters,Al-5Mg-1Si alloy similar to ZL303 alloy in components can be prepared. The hardness of the prepared alloy is approximate to that of ZL303. In addition,the microstructure of the alloy is observed by OM （optical microscope）. Meanwhile,the roles of Zn and Sn in liquid sintering system were analyzed by XRD（X-ray diffraction）.关键词：Powder Metallurgy;Al-Mg Alloy;Sintering;Processing Parameters
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发布时间：2023-12-18 - 摘要：Stainless steel thin film on the aluminum alloy foils was deposited by DC （direct current） magnetron sputtering to improve the defects of inhomogeneous structure,low clearness and low hardness. The samples were tested by frictional testing and salt spray testing,micro-hardness testing and thin film thickness testing,and the sample surface morphology was observed by SEM （scanning electron microscope） and OM （optical microscope）. The results reveal that with sputtering power of 300W,deposited stainless steel thin film with uniformly compact fine grain exhibits desirable brightness and bonding with the matrix alloy as well as corrosion resistance to some extent,leading to the increase of wear resistance and hardness.关键词：DC Magnetron Sputtering;Aluminum Foil;Stainless Steel;Thin Film
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发布时间：2023-12-18 - 摘要：Key points about gauger-classification of large ship propeller were described based on the full understand of casting process. Casting process design and molding,smelting and pouring of liquid copper alloy and machinery for the large ship propeller were approached,and sand mold and low pressure casting for the propeller was introduced. Defects often encountered in the propeller and its prevention were presented.关键词：Casting Process;Large Ship Propeller;Defects
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发布时间：2023-12-18 - 摘要：Ni-based powder that can form the cladding coating with 10 mm in thickness and smooth surface and gas hole-crack free is successfully prepared based on the analysis of powder materials requirements in laser cladding process. The results reveal that the thermal expansion coefficient of the Ni-based cladding coating is less than that of 45# steel matrix,resulting in the absence of crack in pressure during solidification. Fe and Co elements in powder are beneficial to improving the properties of the cladding coating to decrease the crack susceptibility. Non-complete bulk amorphous phase in the Ni-based cladding coating can be observed,which can greatly improve the crack resistance of the cladding coating because of its desirable mechanical properties.关键词：Laser Cladding;Ni-based Alloy Powder;Crack;Thermal Expansion Coefficient;Amorphous Phase
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发布时间：2023-12-18 -
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