最新刊期
卷 32 ， 期 12 ， 2012
- 摘要：The A390 aluminum alloy cylinder liners were prepared by gravity-casting and squeeze-casting,and their fracture behaviors under static loading were investigated by in situ SEM observation.For the gravity-casting alloy,microcracks firstly initiated at the primary Si particles however were restricted from propagating to the matrix.Meanwhile,the eutectic Si particles with a high aspect ratio played a bridging role in the dominant crack propagation,which suggested that the eutectic Si particles are more advantageous to crack propagation than primary Si particles in the gravity-casting alloy.By contrast,for the squeeze-casting alloy,microcracks also were observed to initiate firstly at the primary Si particles but then propagate to matrix and link with other microcracks to form a dominant crack.In addition,microcracks barely initiated at the spherical eutectic Si particles,and the primary Si particles were preferentially sought out by the dominant crack.The results indicate that the eutectic Si particles are in competition with primary Si particles in propagating the dominant crack.Moreover,the fracture of eutectic Si particles affect the propagation of microcracks at the primary Si particles due to the function of the eutectic Si particles to release stress.It also suggested that the primary Si particles and eutectic Si particles should be coordinated to achieve excellent mechanical properties of hypereutectic aluminum-silicon alloys.关键词：A390 Aluminum Alloy;Cylinder Liner;In Situ SEM Tensile;Fracture Behaviors;Primary Si;Eutectic Si
- 2
- |
- 241
- |
- 1
发布时间：2023-12-18 - 摘要：The microstructures and aging characteristics of ultrasonic and traditional casting 7050aluminum alloys were investigated.The results show that,compared with the traditional casting alloy,the ultrasonic casting alloy is characterized with a finer microstructure,and aged time is decreased with easier aging-strengthened.For the hot-rolled plate,peak strength appears in the ultrasonic treated alloy with aging at 120℃ for 8hours,where tensile strength,yield strength and elongation reach 602MPa,547MPa,12.7%,respectively,while peak strength occurs in the traditional casting alloy with aged at 120℃ for 12hours,where tensile strength,yield strength and elongation are 536MPa,462MPa and 15.0%,respectively.关键词：7050 Aluminum Alloy;Traditional Casting;Ultrasonic Casting;Microstructure;Aging
- 2
- |
- 136
- |
- 2
发布时间：2023-12-18 - 摘要：Zirconia coating was prepared on Al-Si alloys by plasma electrolytic oxidation（PEO）in the alkaline electrolyte containing Zr（OH）4 powders.The composition and structure of the coating were investigated by SEM（scanning electron microscope）and XRD（X-ray diffraction）.The results show that in the initial stages of oxidation,the growth of coating belongs to the stage of anodic oxidation controlled by electrochemical polarization.The growth of coating is characterized by outward growth with a faster growth rate.With increasing in time and thickness of the coating,the growth of coating is characterized by in-growth with the decrease of growth rate.The coating consists of t-ZrO2,m-ZrO2,α-Al2O3 and γ-Al2O3,in which t-ZrO2 is dominant in phase with distributed in outer layer of the coating,while α-Al2O3 appears in inner layer of the coating.The coating surface exhibits particle structure with size of 1～2μm.In the process of plasma electrolytic oxidation,Zr（OH）4powders move and deposit on the mouth of plasma discharge channel under electric field force to transform into ZrO2 as a result of the high temperature of plasma discharge.关键词：Al-Si Alloys;Zirconia;Plasma Electrolytic Oxidation;Coating
- 2
- |
- 93
- |
- 1
发布时间：2023-12-18 - 摘要：<正>由于日元持续停留在强势水平,更多的日本车企开始采购较廉价的外国产零部件。作为日本第二大汽车制造商,日产正在扩大国外采购并计划"于2016财年将进口零部件在日本国内组装汽车中的零部件比例扩大至40%以
- 2
- |
- 27
- |
- 0
发布时间：2023-12-18 - 摘要：Effect of electric pulse on the solidification structure of high-boron middle-carbon alloy steel was investigated by exerting electric pulse on the alloy steel during solidification process.The results indicate that,after electric current pulse treatment,grains of high-boron middle-carbon alloy steel are refined and spheroidized with more uniform distribution.Martensite lamellar spacing is decreased,and volume fraction of hard phase is decreased from 10.6% in non-electric pulse treatment to 8.3%,however,alloying elements,such as W,Cr,Mo,V in matrix are increased.In addition,hardness of matrix is improved from HV664 to HV739.Net-like hard phase exhibits discontinuous and isolated spheroidization.The co-action of Joule heat,magnetic-electric force and electric migration of electric pulse is responsible for the above effects.关键词：Electric Pulse;High-Boron Middle-Carbon Alloy Steel;Grain Refinement;Hard Phase
- 2
- |
- 80
- |
- 2
发布时间：2023-12-18 - 摘要：The modification of antimony（Sb）on eutectic Si phase in A356aluminum-silicon alloy and the effects of rare earth（RE）on the modification efficiency of antimony were investigated,and effects of the strontium（Sr）on A356 alloy were analyzed comparatively.The tensile and fatigue properties of the Sb,Sb+RE or Sr modified A356 alloys were also analyzed comparatively.The results show that Sb can refine the eutectic silicon phases in A356 alloy significantly from plate-like into fine fibrous structure.However,the modification efficiency of Sb is lower than Sr.The modification effects can be improved obviously in Sb modified A356 aluminum-silicon alloy with the addition of a little RE,decreasing of Sb content for achieving the desirable modification efficiency.The tensile properties of the Sb or Sb+RE modified A356 alloys are lower than those of the Sr modified alloy,however,the fatigue properties are superior to that of the Sr modified alloy,which may be attributed to the higher compactness and less casting defects in Sb or Sb+RE modified alloys compared with the Sr modified alloy.关键词：A356 Alloy;Sb Modification;Rare Earth（RE）;Eutectic Silicon Phase
- 2
- |
- 238
- |
- 3
发布时间：2023-12-18 - 摘要：The casting forming of large-sized complicated thin-walled castings has been one of notorious problem,especially the casting of superalloy with high melting point and wide solidification interval.Counter gravity casting（CGC）belongs to a acceptable choice for production of high quality thin-walled castings.The processing principle,developing status,characteristics and applications were reviewed for counter gravity casting including vacuum suction,low pressure casting,differential pressure casting and adjusted-pressure casting.Present status of CGC application to superalloy large complicated thin-walled casting was surveyed.Subsequently,the technical bottleneck of the counter gravity casting technology in the superalloy large complex thin-walled castings was pointed out,and prospects of counter gravity casting techniques in the future were described.关键词：Superalloy;Thin-Walled Castings;Counter Gravity Casting
- 2
- |
- 679
- |
- 1
发布时间：2023-12-18 - 摘要：Developing status of die casting industry at home and abroad was reviewed,and driving factors and mechanism of development of die casting industry in future was put forward.In addition,based on the developing routes of die casting industry at home,the life period of die casting industry was classified.The developing tendency of die casting industry at present and next decade was proposed.关键词：Die Casting;Industry;Life Period
- 2
- |
- 348
- |
- 2
发布时间：2023-12-18 - 摘要：In the past decade,a wide varieties of Mg-based bulk metallic glasses（BMGs）with high glassforming ability（GFA）were developed,showing a significant progress.Mg-TM-RE（TM:transition metal,RE:rare earth metal）alloy system was the main one.The newly developed Mg-TM-RE BMGs and their GFA were reviewed.Furthermore,the effects of alloying elements TM and RE on the GFA were discussed in details,providing new ideas for Mg-TM-RE alloy design.关键词：Metallic Glasses;Magnesium Alloy;Glass Forming Ability;Alloying Elements
- 2
- |
- 102
- |
- 1
发布时间：2023-12-18 - 摘要：<正>广西柳工机械股份有限公司核心铸件研发制造项目日前在广西柳州鹿寨县经济开发区鹿寨工业园奠基,这标志着柳工铸造业向高端铸件迈进,将为公司在国内国际市场占据重要竞争地位提供有力的支撑。柳工股份公司总裁曾光安说,柳工工程机械核心铸件研发制造项目的开工建设,是柳工在国际化
- 2
- |
- 20
- |
- 0
发布时间：2023-12-18 - 摘要：<正>压铸工艺的诸多特点,使其在提高有色金属合金铸件的精度水平、生产效率、表面质量等方面显示出了巨大优势。随着汽车、摩托车等工业的发展,以及提高压铸件质量、节省能耗、降低污染等设计要求的实现,有色金属合金压铸件、特别是轻合
- 2
- |
- 91
- |
- 0
发布时间：2023-12-18 - 摘要：<正>山西省重点工程太重集团榆次液压铸造项目开工建设。项目引进世界顶级的液压铸造技术,生产高压柱塞泵、多路阀等产品铸件。这个项目联合已投入使用的液压系统等,共同建成国内首家液压产品自主化产业示范基地,彻底结束我国高压、高精密液压铸件长期依赖进口的历史。
- 2
- |
- 31
- |
- 0
发布时间：2023-12-18 - 摘要：<正>据彭博社6月12日消息,麦格理集团的分析师Jim Lennon称,今年上半年中国的铝消费量可能已较上年同期增长了逾10%,且今年下半年增长加速。商品研究部门的主管Lennon在芝加哥参加Harbor Intelligence主办的会议上称:"数据显示中国今年上半年铝消费量或已增长逾10%。"摘自《中华压铸网》
- 2
- |
- 23
- |
- 0
发布时间：2023-12-18 - 摘要：The rheological die forging forming of A356 semi-solid slurry which was treated by self-developed power ultrasonic double-sound field apparatus was performed on the YB32-200 four pillars hydraulic machinery to understand microstructure and mechanical properties of the parts formed after and before T6 treatment at 625,615,605℃.The results show that the α-Al+Si eutectic phase is dissolved into primary α-Al phase,and fine Mg2Si dispersoids are generated in the alloy parts during ageing process.Tensile strength and elongation are improved,where the tensile strength reaches 241.20MPa at 615℃,and the elongation rate reaches 17.88% at 605℃.关键词：A356;Power Ultrasound;Rheological Die Forging;T6 Treatment
- 2
- |
- 75
- |
- 2
发布时间：2023-12-18 - 摘要：Filling and solidification process of gear wheel room with different gating system were simulated by FEM（finite element method）software.The defects positions at the part in the casting process were predicted.The simulation results show that the design of the gating system has a significant effect on filling process,solidification time and the size and position of casting defects.The liquid alloy is filled smoothly with optimized design,and the defects in the part are reduced obviously,improving the whole quality of aluminum alloy die castings.关键词：Die Casting;Numerical Simulation;Filling Process;Solidification Time;Casting Defects
- 2
- |
- 94
- |
- 3
发布时间：2023-12-18 - 摘要：ZL105 alloy was prepared with ZL102 alloy,pure aluminum,copper plate and Mg ingot.Effects of processing parameters on the mechanical properties and microstructure of squeezing castings were investigated by orthogonal testing.The results show that the influencing factors on strength of the squeezing castings are as follows:pouring temperature,holding time,pressure,and dominant factors on plasticity is pouring temperature.The dominant factor influencing mechanical properties and microstructure of the squeezing castings is pouring temperature.Tensile strength of the permanent mold castings after heat treatment reaches 225.0 MPa,while tensile strength of squeezing casting after heat treatment reaches 249.8 MPa,improved by 11.0%.关键词：Squeezing Casting;ZL105 Alloy;Microstructure and Properties
- 2
- |
- 198
- |
- 2
发布时间：2023-12-18 - 摘要：The reasons of causing oversize of planar profile tolerance of secondary machining for ETC throttle valve body was analyzed carefully,which was attributed to the problems in measuring methods of planar profile tolerance and cutting methods of Rbase level.Based on amounts of data experiments,through using methods of standardized planar profile tolerance and roughing and finishing for Rbase level,the defects of oversize of planar profile tolerance can be totally eliminated.关键词：Throttle Valve Body;Secondary Cutting;Planar Profile Tolerance;Oversize
- 2
- |
- 37
- |
- 1
发布时间：2023-12-18 - 摘要：The structural characteristics and technological requirement of small stainless steel CF8 parts were analyzed.Through analyzing technological features of shell-making and core-making for investment parts with various blind holes and narrow-long slot and theirs applicable conditions,special technological design was presented,and mechanical cold-straightening was used.Combining with special tool-equipment and tool-safety measures,the chemical compositions were determined.Through the above measures,the difficulty of shell-making for narrow-long slot in the investment parts was overcame effectively,realizing the production of special narrow-long slot in the parts with simplified technology.Meanwhile,the production exhibits stable reliability with desirable quality of production-volumetric parts.关键词：Stainless Steel CF8 Parts;Narrow-Long Slot;Austenite;Cold-Straightening
- 2
- |
- 59
- |
- 0
发布时间：2023-12-18 - 摘要：The structure characteristics of the impeller and the processing scheme were analyzed,and the process pinch deformation form was discussed.Meanwhile,the feasible tools and advanced detection methods and principles were put forward,ensuring the processing quality and improving the production efficiency,reducing the cost.Trial production shows that impeller quality meets the requirements of design.关键词：Impeller;Tool-Assembling;C354 Alloy
- 2
- |
- 101
- |
- 0
发布时间：2023-12-18 - 摘要：The temperature field and solidification field of the gas turbine blade during investment casting process have been simulated by using the Procast software to understand the effects of the pouring temperature on the blade porosity.The simulation results indicate that the shrinkage porosities in the blade root and airfoil are reduced with the increase of pouring temperature.The shrinkage porosities are decreased significantly by placing chiller and insulation cotton on proper location of the mold.Optimized process was presented.Practical experimental results were well in agreement with the simulation ones in shrinkage porosity location and change in the blades.关键词：Heavy-Duty Gas Turbine Blade;Investment Casting;Numerical Simulation;Shrinkage Porosity
- 2
- |
- 150
- |
- 1
发布时间：2023-12-18 - 摘要：Pouring and product process as well as key technological points of permanent mold casting aero fuze rotor were described,and processing procedures including choice of various parameters were presented.The center-sprue was designed to simplify mould structure based on the comprehensive conditions.关键词：Pouring;Melting;Pouring Temperature
- 2
- |
- 54
- |
- 2
发布时间：2023-12-18 - 摘要：Quartz powder and diatomite powder were used as refractory aggregate of casting coating for EPC.Combined with CMC,sodium bentonite was chosen as suspending agent,and dextrin and sol silicate were mixed up to be taken as compound binder.After the ratio of refractory aggregate was determined,the optimized coating formula was presented based on orthogonal testing.By performance testing,the coating exhibits excellent performance with low cost.关键词：EPC;Coating;Magnesium Alloy;Orthogonal Testing
- 2
- |
- 164
- |
- 0
发布时间：2023-12-18 - 摘要：Adding 4% dust as sintering aid in the single silica powder refractory aggregate,it was sintered at 1 400℃ and 1500℃,and BST 401 bending strength tester was used to measure the bending strength of sintered samples.Meanwhile,compared with the single silica powder aggregate,the sintering mechanism of the refractory aggregate contained 4% dust was analyzed.The results show that liquid sintering of the silica powder is promoted with the dust addition,however,absence of effect on the solid sintering can be observed.During the sintering process,liquid sintering exhibits dominant role in the sintering process.The sintered samples were observed by a scanning electron microscope（SEM）.Appropriate amount of liquid phase is generated in the refractory aggregate at 1 500℃,and sintered samples exhibit desirable structure,meeting the requirements of the refractory aggregate in the coating for cast in steel evaporated pattern casting.关键词：Dust;EPC;Coating For Steel Casting;Refractory Aggregate;Sintering Mechanism
- 2
- |
- 93
- |
- 1
发布时间：2023-12-18 - 摘要：Internally finned copper tubes with 10mm in outer diameters were produced by horizontal heated mold continuous casting.The results show that internally finned tubes with complex profile can be produced by horizontal heated mold continuous casting process through controlling solidification interface location in mould wall to reduce the friction force between tubes and mould wall,realizing the practical continuous casting.Meanwhile,periodic scar on tube surface can be eliminated,obtaining smooth surface and realizing near net-shape forming.Forming principle of the tubes and origination of hot crack and cold shut in the tubes during heated mold continuous casting were approached.关键词：Heated Mold Continuous Casting;Internally Straight Finned Tube;Copper Tube
- 2
- |
- 82
- |
- 1
发布时间：2023-12-18 - 摘要：Al2O3 particulate reinforced steel matrix composites were fabricated successfully by squeezing casting through coating a thermal insulating ceramic layer on the internal surface of the mold.The cooling rate of the molten steel can be decreased greatly with the help of the ceramic layer,and the key problems in fabrication of steel matrix composites,such as very high cooling rate,poor infiltration ability with the molten steel,which result in difficulty in fabrication of the composites,are solved.The Al2O3p/40Cr steel matrix composites with 6mm in thickness and 56% Al2O3 particles in volume fraction were successfully fabricated by squeezing casting with 8MPa pressure.The as-cast and heat treated microstructure,hardness,wear resistance of the composites prepared were investigated.The results show that the compact microstructure in the composites with fine grain can be observed.The macro-interface between the substrate and composites layer is tranferred naturally,and the micro-interface between Al2O3particles and the matrix exhibits dense without any cavities.The wear resistance of the composites is 8.7 times higher than that of the 40Cr substrate.关键词：Squeezing Casting;Al2O3p/Steel Composites;Fabrication;Thermal Insulating Mold
- 2
- |
- 221
- |
- 6
发布时间：2023-12-18 - 摘要：Cu-0.86Cr alloy was prepared using solution-treated,cold deformation and aging treatment with and without DC electric current.Influences of DC electric current on microstructures and mechanical properties of thermally aged Cu-0.86Cr alloy were examined.The results show that the aging time for the alloy to reach maximum tensile strength can be shorten with the decrease of the peak of tensile strength by 28 MPa after DC electric current.Meanwhile,DC electric current can improve plasticity of the alloy.The microstructure observation indicates that the recovery occurs in the alloy during aging process.关键词：Cu-Cr Alloy;DC Electric Current;Aging;Mechanical Properties
- 2
- |
- 85
- |
- 3
发布时间：2023-12-18 - 摘要：Changes of the interfacial IMC（intermetallic compound）morphologies and the shear strength of Sn-0.3Ag-0.7Cu/OSP,ENIG finishes solder joints were evaluated under different aging conditions.The results indicate that:（1）The interfacial IMC thickness between the two type of finishes and Sn-0.3Ag-0.7Cu solder is increased with increasing in aging time,and the growth rule follows parabolic rule.However,the growth rate of the interfacial IMC with OSP finish is higher than with ENIG finish,and the IMC morphologies gradually transform into the flat wave-shaped.（2）The shear strength of Sn-0.3Ag-0.7Cu/OSP,ENIG finishes solder joints is decreased with increasing in aging time.With aging at lower temperature,the shear strength of the solder joint with ENIG finish is higher than that with OSP finish.However,the shear strength of the solder joint with ENIG finish is lower than that with OSP finish with aging at higher temperature.关键词：Sn-0.3Ag-0.7Cu Solder;OSP;ENIG;Aging;IMC Morphology;Shear Strength
- 2
- |
- 193
- |
- 2
发布时间：2023-12-18 - 摘要：Fine-grained ZK60 magnesium alloy sheets were joined by CO2 laser beam welding.The effects of welding parameters on microstructures and mechanical properties of the joints were investigated,and the welding characteristics of fine-grained magnesium alloy were analyzed.The results show that a favorable weld joint without distortion and liquation cracking in PMZ can be observed under the suitable processing parameters.The ultimate tensile strength（UTS）and elongation reach up to 295MPa and 11.7%,which are 91% and 62% of the base metal,respectively.The width of cellular and columnar grains at the fusion boundary is about 20μm,and the fusion zone is characterized by equiaxed grains.The difference in the grain size from the fusion center to the HAZ and to BM is lower than 3μm.The fracture mechanism is characterized by ductility mode.关键词：Fine Grain;ZK60 Magnesium Alloy;Laser Beam Welding;Microstructure;Mechanical Properties
- 2
- |
- 153
- |
- 2
发布时间：2023-12-18 - 摘要：Al-4.5Zn-1.0Mg-0.8Cu alloys containing different RE content were prepared by metal mould casting.Effects of RE on microstructure and mechanical properties of Al-4.5Zn-1.0Mg-0.8Cu alloy were investigated by tensile testing,OM（optical microscovpe）,SEM（scanning eldctron microscope）and EDS（energy dispersive spectrometer）.The results show that the tensile strength and elongation are increased firstly,and then decreased with the increase of RE content.The alloy with 0.12% RE（mass fraction）exhibits the desriable mechanical properties.With proper RE,secondary dendrite arm spacing can be decreased,and RE is distributes mainly at grain boundaries and dendrite boundaries in form of AlZnMgCuRE phase.Excessive RE can cause over-modification effect,increasing secondary dendrite arm spacing.With a lower RE content,AlZnMgCuRE phase exhibits rod-like shape,and with excessive RE,AlZnMgCuRE phase becomes coarse block structure,which can weaken the mechanical properties as a result of cutting effects.In addition,RE can promote the solid solution of Mg and Zn in Al melt,improving the solid solution strengthening effects.关键词：Rare-Earth;Al-4.5Zn-1.0Mg-0.8Cu Alloy;Mechanical Properties;Microstructure;Fracture Surface
- 2
- |
- 192
- |
- 8
发布时间：2023-12-18 - 摘要：Effects of the low voltage pulsed magnetic field（LVPMF）on solidification structure of 2024 wrought aluminum alloy were investigated,and the effects of pouring temperature and discharging voltage on morphology and size of α-Al phase in 2024 wrought aluminum alloy were observed.The results show that primary and eutectic phase in the alloy can be refined obviously by LVPMF.With the pouring temperature near to liquidus temperature increasingly,the average grain size is refined gradually.With the increase of discharging voltage,average grain size of primary α-Al particles is decreased.With discharging voltage of 250V,average grain size of primary α-Al particles reaches minimum values.关键词：Low Voltage Pulsed Magnetic Field;2024 Wrought Aluminum Alloy;Solidification Microstructure;Pouring Temperature;Discharging Voltage;Refinement
- 2
- |
- 268
- |
- 5
发布时间：2023-12-18 - 摘要：Combination effects of Sc/Zr on the microstructures and properties of Al-Si alloys were investigated.The results show that the Sc addition can not only refine the eutectic colony and form the Sc containing precipitates in Al-Si alloys,but also take part in the formation of AlCuNi high temperature phase,and then influence its morphology and distribution.As a result,the hardness and strength of AlSi alloys are improved,especially the high temperature strength.Combination addition of Zr and Sc,can enhance the refinement efficiency of Sc on the eutectic colony and reduce the content of Sc in the Sc containing precipitates.Therefore,Sc can take part in the formation of much more AlCuNi phase.关键词：Al-Si Alloys;Sc;Zr;Combination Effects
- 2
- |
- 217
- |
- 1
发布时间：2023-12-18 - 摘要：<正>宴乐渔猎攻占纹壶（见下页）战国（公元前475年～前221年）通高31.3cm青铜四川成都出土故宫博物院藏商代和西周的纹饰和铭文均铸造而成。随着冶铁业兴起,钢铁工具的出现,自春秋晚期开始,青铜器上出现刻纹形成的纹饰和铭文,到战国时期臻于成熟。战国时期的思想家荀子在《荀子·劝学篇》中说:"锲而不舍,金石可镂"。战国的薄壁青铜器上刻有细如毫发的纹饰并不罕见。青铜器刻纹大致有两种方法:春秋晚期和春秋战国之交是刻出由楔形点（首部较粗深,尾部细浅）组成类似虚线的刻纹。战国早中期开始,虽刻成线条但也不连贯而是分段刻出。两种方法的先后出
- 2
- |
- 209
- |
- 0
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