最新刊期
卷 29 ， 期 12 ， 2009
-
-
-
-
-
-
-
-
-
-
-
-
-
- 摘要：Effects of different quenching agents on the corrosion resistance and microstructure of as-forged Al-6.5Zn-2.65Mg-2.2Cu-0.3Sc-0.13Zr alloy were investigated by intergranular corrosion,exfoliation corrosion,SEM（scanning electron microscope）and TEM（transmission electron microscope）.It is shown that corrosion resistance of the T6 treated alloy is seriously deteriorated by quenching at air.The exfoliation corrosion resistance of T6 treated alloy by quenching at ambient water is obviously superior to that of one by quenching at ambient oil.The corrosion resistance of corresponding T6 treated alloy is distinctly improved after 80℃/30s water quenching and ambient water quenching or 80℃/30s oil quenching and ambient water quenching,which is attributed to the change of size and distribution of precipitates from the grain boundary by pre-quenching at 80℃.关键词：Al-Zn-Mg-Cu Alloy;Quenching;Intergranular Corrosion;Exfoliation Corrosion;Microstructure
- 2
- |
- 167
- |
- 2
发布时间：2023-12-18 - 摘要：Effects of different solidified velocities on microstructure of directional solidification Al-17.5In monotectic alloy were investigated.The results show that regular indium fibres precipitated from the alloy by monotectic reaction are regularly arranged in the Al matrix at large gradients and low solidification velocities,while with increasing in solidification velocity,the indium fibres are gradually converted into pearl-string structure.The transformation of the structures is described,and a new criterion for the destabilization of regular indium fibrous growth in directionally solidified Al-17.5In monotectic alloys is derived.关键词：Al-17.5In Monotectic Alloy;Directional Solidification;Morphology Transformation;Criterion
- 2
- |
- 97
- |
- 1
发布时间：2023-12-18 - 摘要：The microstructure,mechanical properties and tensile fracture morphology of Ti53.5Ni22.8Cu23.7 shape memory alloy ribbons fabricated by rapid solidification were investigated by transmission electron microscope（TEM）,electron probe microanalysis（EPMA）and tensile testing.The results show that tensile fracture stress and strain of as-cast ribbons reach 1 257 MPa and 3.86%,respectively,and the fracture morphology exhibits typical vein fringe and amorphous featureless zone.Tensile strength of the ribbons is reduced to 623MPa and 850MPa,respectively,after annealed at 450℃ for 10 min and 1 hour,meanwhile,with increasing in strain,elastic modulus of the ribbons is improved from 710GPa to 25GPa.Fracture morphology of annealed ribbons exhibits equiaxed grain.The TEM features of the ribbons annealed at 450℃ for 1 hour are different before and after tensile testing.Some martensite variants originated from martensite transformation induced by tensile stress can be observed in local austensite grain after tensile testing.关键词：Rapid Solidification;Ti-Ni-Cu Alloy;Fracture Morphology;Tensile Curves
- 2
- |
- 122
- |
- 0
发布时间：2023-12-18 - 摘要：SiC particulate reinforced magnesium matrix composites SiCp/AZ31 were successfully prepared by repeated plastic working（RPW）combining with hot extrusion.Effects of cycling’s times（times of RPW）on microstructure and properties of the composites were investigated.The results indicate that the RPW can refine grain sizes of AZ31 alloy and SiC particles,and uniformly distribute the SiC particle in the matrix alloy.In addition,it can not only remarkably enhance tensile strength and hardness of the composites,but also improve its plasticity.With 4% SiC particle in volumetric fraction,the ambient tensile strength and hardness of the composites can reach up to 359MPa and 107,respectively,after 300 times RPW cycling by hot extrusion,in which grain size of the matrix alloy is refined to 20 μm and SiC particles are refined to below 3 μm,dispersedly distributed in the matrix alloy.关键词：RPW;Particle Reinforced;Magnesium Matrix Composites;AZ31 Magnesium Alloy;SiC Particle
- 2
- |
- 128
- |
- 1
发布时间：2023-12-18 -
-
-
-
-
-
-
-
-
- 摘要：Effects of composition and heat treatment on properties of Cu alloy were investigated by component orthogonal testing.The results show that hardness and electric conductivity of the Cu alloy are closely related to mass ratio of Ni to Si.With Ni/Si of 5,although electric conductivity of the Cu alloy is slightly changed,desirable strengthening effects on the Cu alloy can be observed.Meanwhile,the properties of the Cu alloy are also dependent on the solid solution treatment,aging treatment and cold forging.The high-strength and high conductivity Cu alloy with excellent mechanical properties and electric properties was successfully prepared,and the hardness and electric conductivity of the prepared Cu alloy reach HB181 and 14.94MS/m,respectively.关键词：High Hardness;High Conductivity;Copper Alloy;Orthogonal Method
- 2
- |
- 505
- |
- 2
发布时间：2023-12-18 - 摘要：Nano-SiO2,with large specific surface area and numerous uncoupled surface atoms,has ability of combine physically and chemically with resin matrix strongly to strengthen and toughen resin.Nano-SiO2 was uniformly dispersed in water soluble phenol-formaldehyde resin by simple co-blended process and by ultrasonic dispersing solution co-blended process,respectively.Effects of nano-SiO2 on mechanical properties of resin coated sand were investigated by testing compressive strength of modified resin coated sand,and the optimized nano-SiO2 content for modification of resin was presented.Dispersed difference of nano-SiO2 particles in resin matrix by simple co-blended process and in solution co-blended process was analyzed by SEM.Results show that ultrasonic dispersing solution co-blended process is superior to simple co-blended process in dispersing nano-SiO2 particles into phenol-formaldehyde resin to greatly improve the mechanical properties of the resin.However,with excessive nano-SiO2,mechanical properties of the resin are deteriorated as a result of occurrence of easy aggregation.The optimized fraction of nano-SiO2 is 3% of the resin mass by experimental testing.关键词：Nano-SiO2;Resin Coated Sand;Phenol-formaldehyde Resin;Solution Co-blended Process;Mechanical Properties
- 2
- |
- 100
- |
- 1
发布时间：2023-12-18 - 摘要：Effects of hot extrusion parameters on mechanical properties and microstructure of the 7055 alloy were investigated by tensile testing and microstructural observation,and they are compared with those of as-cast ones.The results reveal that microstructure and mechanical properties of the hot extruded 7055 aluminum alloy are obviously superior to those of as-cast ones.Meanwhile,with increasing in specific pressure,grain size in the microstructure of the alloy is increasingly refined,and tensile strength is gradually improved.With extrusion casting at 730℃ and 75MPa,the grain size in the alloy after T6 heat treatment is refined obviously with tensile strength of 681.4MPa and elongation of 7.14%.关键词：7055 Aluminum Alloy;Hot Extrusion;Mechanical Properties;Microstructure
- 2
- |
- 608
- |
- 5
发布时间：2023-12-18 - 摘要：Electroless nickel-plating on AZ91D magnesium alloy by using NiSO4·6H2O as main salt was described.Permanganate and phosphate chemical conversion films were proposed as the chrome-free pretreatment layer between electroless nickel-plating and AZ91D magnesium alloy substrate.Morphology,composition and corrosion resistance of the chemical conversion film and electroless nickel-plating layer in 3.5%NaCl solution were determined by SEM,EDX,XRD and polarization curve.The results show that the electroless nickel-plating coating after permanganate pretreatment exhibits cell structure with sound to some extent and micro-crack,while one after phosphate pretreatment also exhibits cell structure with uneven grain size and micro-crack free,and plating coating shows uniform thickness with compact structure and pore-free.Corrosion resistance is slightly improved by chemical conversion treatment compared with that of magnesium substrate,and corrosion potential of electroless nickel-plating coating after permanganate pretreatment and phosphate pretreatment reach-0.48Vsce and-1.12Vsce,respectively,in 3.5%NaCl solution by polarization curves.Corrosion resistance of AZ91D magnesium alloy is improved by electroless nickel-plating layers after phosphate pretreatment with NiSO4·6H2O as main salt.关键词：AZ91D Magnesium Alloy;Chrome-free Pretreatment;NiSO4·6H2O;Electroless Nickel-plating
- 2
- |
- 348
- |
- 3
发布时间：2023-12-18 - 摘要：Flow behavior and formation of transverse welding joint of aluminum alloy during billet-to-billet extrusion process were investigated by the 3D finite element method.The results show that,the aluminum alloy exhibits heterogeneous rheo-forming behavior during extrusion process,and a gas gap is formed at the interface top of new billet and old billet.Meanwhile,a transverse welding joint can be observed at interface in role of high pressure and shearing deformation.Factors influencing quality of transverse welding joint were described.The simulated results reveal that the product length with transverse welding joint can be greatly shortened by adjusting length of cone surface of the flat cone die.关键词：Billet-to-billet Extrusion;Transverse Welding Joint;3D FEM
- 2
- |
- 150
- |
- 1
发布时间：2023-12-18 - 摘要：Calculation models of electromagnetic field in semi-solid slurry prepared by electromagnetic stirring（EMS）were established,and effects of stirring current,stirring frequency,crucible material,gap width between coil and crucible on magnetic flux density were analyzed by the Anasys software with corresponding experimental verification.The results reveal that simulated results are well in agreement with those of experimental ones,showing the availability of calculation model and software.Rotary flow appears in the aluminum alloy melt at horizontal direction in role of electromagnetic forces.Electromagnetic forces are decreased from edge to center in the alloy melt as a result of skin effects of induced current.Magnetic flux intensity is decreased with increasing in current frequency and it is increased with increasing in current.The maximum magnetic flux intensity can be observed with gap width of 5mm between crucible and coil in stainless steel crucible.The uniform fine structure in the semi-solid slurry can be generated with stirring at 10Hz and 50A.关键词：Electromagnetic Stirring;Semi-solid Slurry;Numerical Simulation;ANSYS Software
- 2
- |
- 218
- |
- 4
发布时间：2023-12-18 - 摘要：Effects of technological parameters in strong cooling with single-tube on microstructure of A356 alloy semi-solid billets were described.The results show that fine grain in prepared billets is approximately spherical structure with pouring at 640650℃ and cooling at 180L/h,meeting the requirements of semi-solid forming for billets.关键词：Strong Cooling with Single-tube;Semi-solid;A356 Alloy;Processing Parameters;Microstructure
- 2
- |
- 56
- |
- 2
发布时间：2023-12-18 - 摘要：40Cu-W cup shell was successfully prepared by thixo-forging pseudo-semi-solid composites presented based on the powder metallurgy technology combining with semi-solid metal forming process.The bending strength and relative density reach 1151MPa and 98.38%,respectively,with forging pressure of 500MPa at 1350℃.The compact and homogeneous microstructure can be observed in the 40Cu-W cup shell.W particle is surrounded by Cu phase tightly,which is responsible for the improvement of mechanical properties of the parts.关键词：40Cu-W Alloy;Pseudo-semi-solid Thixo-forging;Powder Metallurgy;Processing Parameters
- 2
- |
- 141
- |
- 3
发布时间：2023-12-18 - 摘要：Based on analyzing structure features of high quality aluminum alloy pressure-cooker and its technological requirements,mould for permanent mold counter pressure casting and its processing were designed,and processing parameters were determined.In the condition of pouring at 700720℃,pressure of 0.6MPa,lifting velocity of 35 mm/s and filling at 45 mm/s as well as holding pressure for 1520 s,the absence of shrinkage hole（porosity）in the trial-production pressure-cooker can be observed,meanwhile,grain size in the alloy with more compact microstructure is refiner than that of one in low pressure casting,and tensile strength and elongation are higher than 315MPa and 8%,respectively.关键词：Counter-pressure Casting;Aluminum Alloy;Pressure-cooker;Processing Parameters;Mechanical Properties
- 2
- |
- 172
- |
- 1
发布时间：2023-12-18 -
Effects of Vacuum Die Casting Processing Parameters on Mechanical Properties of AM50 Magnesium Alloy
摘要：Systematic high vacuum die casting experiments were conducted using a step-shape die and AM50 magnesium alloy,and density and mechanical properties of the tested specimens with different thickness were measured under different die casting processing parameters to understand the effects of high vacuum die casting processing parameters on mechanical properties of AM50 alloy.The results reveal that with decreasing in vacuum pressure in cavity,density,tensile strength and elongation of the specimens are increased.With increasing in filling pressure,relative density,tensile strength,yield strength and elongation of the specimens are improved.With raising in injection velocity,tensile strength,yield strength and elongation of thin-walled castings are obviously improved,which is contrary to the conventional casting.Tensile strength and elongation of thin-walled castings can be greatly improved by high vacuum combining with high injection velocity.关键词：Vacuum Die Casting;Magnesium Alloy;Processing Parameters;Mechanical Properties- 2
- |
- 347
- |
- 7
发布时间：2023-12-18 - 摘要：Squeezing casting is increasingly rapidly developed in last years,especially filling indirectional squeezing casting.At abroad,the squeezing casting machine suitable for filling indirectional squeezing casting include VV,HV and HH types generally.A leading horizontal HH type squeezing casting machine was developed at home,exhibiting the combination of die casting and squeezing casting.LK/HH type squeezing casting machine can ensure injection punch forward movement along horizontal direction based on a self-developed slow-injection technique to fill the liquid metal into the whole chamber,which can avoid the entrapment-gas in the chamber to eliminate the shrinkage hole（porosity）in the castings.关键词：Squeezing Casting;Filling Indirectional Squeezing Casting;HH Type Squeezing Casting Machine
- 2
- |
- 213
- |
- 7
发布时间：2023-12-18 - 摘要：Deformation rate and principle of die casting aluminum alloy long-thin panel for communication were measured,and origination of deformation was expounded from the viewpoint of panel structure and die casting process.The results reveal that deformation occurs in process of the open-mold and push-out of panel,not occurs in process of cooling.Selection of parting face and allocation of push-pin are mainly responsible for the deformation of die casting panel.The deformation rate of the die casting panel can be greatly reduced by designing rational parting face and push-pin.关键词：Deformation;Aluminum Alloy;Die Casting
- 2
- |
- 112
- |
- 1
发布时间：2023-12-18 - 摘要：Cavity in components with hollow structure is commonly manufactured with ceramic mold core in investment casting.However,manufacturing of ceramic mold core needs a special tool,which exhibits not only high product cost and long period in special tool but also complicated manufacturing process and long period in ceramic mold core so that it can not meet the requirements of development period of new product.A method to produce hollow components with ceramic mold core free is presented to manufacture engine casing,and it is verified by practical production,obtaining desirable effects.关键词：Ceramic Mold;Hollow Castings;Investment Casting
- 2
- |
- 216
- |
- 0
发布时间：2023-12-18 - 摘要：The development status of investment casting industry in China was surveyed,especially effects of financial crisis on export enterprises working for investment castings.The countermeasures,including adjustment of structure,attention of environmental protection and development,were presented,such as adjusting market structure,product structure and customer structure.In addition,enterprise management should be enhanced,and energy-saving should be pay attention to.关键词：Investment Casting;Energy-Saving;Environmental-protection
- 2
- |
- 348
- |
- 1
发布时间：2023-12-18 - 摘要：A new multi-function coating property testing instrument for lost foam casting was described.The testing principle and testing sample making were introduced in detail.And practical coating for lost foam casting was measured by the help of the instrument.The results show that the instrument can rapidly test the transferring ability of degradation product,high temperature permeability and high temperature strength and it exhibits desirable data repeatability.The testing results are well in agreement with the actual ones.关键词：Lost Foam Pattern;Casting Coating;Testing Instrument
- 2
- |
- 154
- |
- 1
发布时间：2023-12-18 - 摘要：Nano-sized SiC particles reinforced aluminum matrix composites were fabricated by mechanical stirring and high-intensity ultrasonic method,and mechanical properties and microstructure of the prepared composites were investigated.The results reveal that compared with those of ADC matrix alloy,the tensile strength,elastic modulus,reduction of area and hardness of the composites are improved by 23%,43%,160% and by 7.4%,respectively,with 2.0% SiC reinforcement in weight percent.The tensile fracture morphology and distribution of SiC particles in the composites were observed by SEM（scanning electron microscope）.It is found that SiC particle is uniformly and dispersedly distributed in the matrix alloy with absence of large cluster.Meanwhile,uniform distribution of nano-sized SiC particle plays the role in inhibiting or restraining the creation and propagation of crack in the composites.关键词：Mechanical Stirring;High-intensity Ultrasonic Desperation Method;Nano-sized SiC Particles;Aluminum Matrix Composites
- 2
- |
- 460
- |
- 9
发布时间：2023-12-18 - 摘要：Effects of electromagnetic stirring on microstructure and mechanical properties of Mg-8Li-3Al alloy were investigated.The results show that tensile strength,elongation and hardness of the alloy are obviously improved by electromagnetic stirring as a result of refining dendrite through improving heat transfer and mass transfer during solidification.With 100V electromagnetic voltage,ambient tensile strength,elongation and hardness of the Mg-8Li-3Al alloy with uniformly fine structure reach 212.9MPa,10.5% and 71.3,respectively.关键词：Electromagnetic Stirring;Mg-Li-Al Alloy;Microstructure;Mechanical Properties
- 2
- |
- 150
- |
- 1
发布时间：2023-12-18 - 摘要：Aiming at the difficulty in purifying the high strength and heat resistant RE magnesium alloy and in mass loss of RE in the alloy,we have developed a flux JDRJ-6 to refine the Mg-Gd-Y（GW103K）alloy to understand effects of the flux containing varied YCl3 content on purification and mass loss of Y element,and it is compared with JDMJ flux and RJ-6 flux.The results reveal that after refined by JDRJ-6+2.5%YCl3,the loss of Y and corrosion rate of the alloy are decreased to 18.12% and 0.837 mg·cm-2·d-1,respectively,while the tensile strength and elongation are improved to 226.25MPa and 4.86%,respectively,obtaining the expected results.关键词：GW103K Magnesium Alloy;YCl3;Refiner;Purification
- 2
- |
- 136
- |
- 0
发布时间：2023-12-18 - 摘要：Microstructure and properties of asynchronous rolling AZ31 magnesium alloy sheets during annealing at 200350℃ for 30120 min were analyzed.Homogenization and grain size in the AZ31 magnesium alloy sheets are nearly independent of the holding time during annealing at 200℃.Recrystallization is basically completed in the alloy sheet with annealing at 300℃ for 30 min and uniformly fine equiaxed grain can be observed,however,with increasing holding time to 60 min,partial recrystallization grain is coarsened.Furthermore,with annealing at 350℃ for 30 min and for 60 min,the completion of recrystallization companying with the coarseness of grain size can be observed.Tensile strength at room temperature and elongation of the AZ31 magnesium alloy sheets with annealing at 300℃ for 30 min reach 315MPa and 33%,respectively,exhibiting desirable properties.关键词：Asynchronous Rolling;Magnesium Alloy;Microstructure;Properties
- 2
- |
- 224
- |
- 1
发布时间：2023-12-18 - 摘要：Effects of rare earth ytterbium（Yb）on microstructure and properties of as-cast and aged AZ91 magnesium alloy were investigated by OM（optical microscope）,XRD（X-ray diffraction）and hardness testing.It is found that 1% Yb addition can refine as-cast structure of AZ91 alloy and effectively restrain the growth of β-Mg17Al12 phase with the transformation from net-work structure into discontinuous ones.The hardness of the alloy is increased as a result of creation of Al11Yb3 phase by XRD analysis.Residual second phase is increased with Yb addition after solution treatment,which can postpone the appearance of peak hardness in the aging curves at 180℃ and delay the occurrence of over-aging process in spite of the value of peak hardness is only slightly changed.关键词：Magnesium Alloy;Yb;Heat Treatment;Microstructure;Vickers Hardness
- 2
- |
- 220
- |
- 1
发布时间：2023-12-18 - 摘要：Effects of Zr element on phase structure,microstructure,Vickers hardness and wear resistance of Ti-xZr-5Mo alloy prepared by non-consumable electric arc furnace were analyzed by XRD（X-ray diffraction）,4XC upside-down microscope for metallography,HV-50A sclerometer and M-200 abrasive machine.The results reveal that Ti-xZr-5Mo alloy is mainly composed of equiaxed α phase,and equiaxed α phase is increased with increasing in Zr content.However,β phase is increased in the annealed alloy during slow cooling rate,which is attributed to Zr element and Mo element stabilizing β phase to room temperature.Meanwhile,with increasing in Zr content,hardness and wear resistance of the alloy are greatly improved.关键词：Ti Alloy;Zr;Microstructure;Hardness;Wear Resistance
- 2
- |
- 69
- |
- 3
发布时间：2023-12-18 - 摘要：General sequence of aging precipitation of Mg2Si phase,viz.α-sss→GP zone→β″→β’→β in Al-Mg-Si/Al-Si-Mg alloy,was described,and crystal structure models of potential metastable precipitates in the sequence were surveyed.The formation or transformation process of these precipitates and their enhancing effects on the alloys were expounded.In addition,effects of excessive Si,Cu and sever plastic deformation on the precipitation process were approached.关键词：Aluminum Alloy;Mg2Si Phase;Aging;Precipitation
- 2
- |
- 740
- |
- 12
发布时间：2023-12-18 - 摘要：A kind of coating for permanent mold casting MB15 magnesium alloy which is composed of ZnO,1.5% H3BO3 and 1.1% alkyl sodium sulfonate and 2.0% Na2SiO3 has been developed.During pouring process,CO2 decomposed from H3BO3 and alkyl sodium sulfonate at high temperature can prevent liquid metal from oxidation and ignition.The protecting effects of H3BO3 and alkyl sodium sulfonate at high temperature were described.The results verify that the coating exhibits desirable protection for liquid Mg alloy at high temperature.关键词：Permanent Mold;Water-base Coating;Magnesium Alloy
- 2
- |
- 165
- |
- 0
发布时间：2023-12-18 - 摘要：Quality factors in producing A356.2 aluminum alloy ingot were described,and origination of influencing quality was analyzed.Through adopting effective control countermeasures,un-qualified ingot was reduced.关键词：A356.2 Aluminum Alloy Ingot;Quality Factors;Controlling Measures;Production
- 2
- |
- 86
- |
- 0
发布时间：2023-12-18 - 摘要：CuZn（40-x）Mgx alloy（x=2%,4%,6%,in atom fraction）was prepared by ingot melting method.Effects of Mg content on melting point,phase transformation temperature and microstructural evolution of the alloy were investigated by OM（optical microscope）,differential thermal analyzer and X-ray diffractometer.The results indicate that with Mg content more than 4%,Cu2Mg phase can be observed in the CuZn（40-x）Mgx alloy.Phase transformation temperature and melting point of the alloy are decreased with increasing in Mg content.关键词：Cu-Zn Alloy;Magnesium Alloy;Phase Transformation;Melting Point
- 2
- |
- 200
- |
- 1
发布时间：2023-12-18 - 摘要：Low cycle fatigue behavior of Cu-Ag alloy for Cu cladding Al contact wire was tested by using different strain amplitude control with varied deformation rate.The results reveal that with increasing in strain amplitude,area of hysteresis loop is increased.With increasing in cycling times,cycling stress is gradually decreased to lead to the appearance of fatigue softening.The cycling period of Cu-Ag alloy with 38% deformation rate is higher than that of one with 19% deformation rate.The fracture morphology of the alloy is composed of crack,crack propagation and rupture.The crack propagation of the Cu-Ag alloy is characterized by transgranular and along-grain model.关键词：Cu-Ag Alloy;Hysteresis Loop;Fatigue Crack;Contact Wire
- 2
- |
- 164
- |
- 4
发布时间：2023-12-18 -
-
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0