最新刊期
卷 37 ， 期 6 ， 2017
- 摘要：The binary Mg-Zn alloys with varied Zn content（ 2,4,6,8,10 and 15,in weight） were prepared,and microstructure and mechanical properties of the as-cast Mg-x Zn alloys were investigated by using an optical microscope（ OM）,X-ray diffractometer（ XRD）,scanning electron microscope（ SEM） and mechanical testing.The results reveal that as-cast microstructure of the alloys is composed of matrix α-Mg and eutectic phases distributed along grain boundaries. With increasing in Zn content,the morphology of eutectic phase is gradually changed from isolated particles into fully continuous net-work structure,and the grain sizes are decreased. In addition,the tensile strength and elongation of the alloys are increased firstly,and then decreased gradually. The elongation of the alloy with 4% Zn reaches maximum value of 10. 78%,while ultimate tensile strength reaches210 MPa in the 6% Zn-containing alloy. With the increase of Zn content,the fracture behavior of the alloys is changed from quasi-cleavage to cleavage fracture.关键词：Mg-Zn Alloy;Zn Content;Microstructure;Mechanical Properties;Fracture Behavior
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发布时间：2023-12-18 - 摘要：QPQ（ Quench-Polish-Quench） treatment was carried out on 316 L stainless steel by nitriding at 600 ℃for varied time（ 60,90,120,150 and 180 min）. The microstructure,phase constituent,hardness and wear resistance of modified surface layer of the 316 L stainless steel were investigated by means of optical microscopy,SEM,XRD,micro-hardness testing and wear resistance testing. The results reveal that after QPQ treatment for316 L stainless steel,Fe3O4 oxidized layer is formed on the top of the compound layer,and middle compound layer consists of Fe2 3N、Fe4N、Cr N and α-N,while the diffusion layer is composed of Cr N and γN. The thickness of the compound layers is increased from 16. 54 μm to 34. 94 μm with the increase of nitriding time from 60 min to180 min,and the thickness of the compound layer exhibits parabolic relation with the nitriding time. The microhardness of QPQ treated samples is increased by 4 6 times higher than that of the untreated sample,and the maximum microhardness value of 1 040. 1 HV0. 2can be obtained after nitriding for 150 min. With prolonging nitriding time,the surface hardness is decreased due to the porosity in the surface layer. The wear resistance of316 L stainless steel can be improved significantly by QPQ treatment,and the optimum nitriding duration for improving the wear resistance is 150 min. The worn surface morphology reveals that the un-treated samples are characterized by adhesive wear,so wear rate is the higher.关键词：QPQ Treatment;Nitriding Time;316L Stainless Steel;Microstructure;Wear Resistance
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发布时间：2023-12-18 - 摘要：By using the automatic CO2 gas protection welding with ABB welding robot for 12 mm thick Q345 steel plate with V groove,butt joint welding process testing was carried out to understand effects of different welding process parameters on microstructure and properties of welding joint. The results reveal that with wire feeding speed matching with welding velocity,droplet exhibits short-circuit transition with low spatter,so welding seam with desirable quality can be obtained. Absence of defects,such as gas hole,crack and undercut,can be observed in the surface of the joint. With increasing in feeding wire speed and welding current,the joint has the worse forming quality as a result of over-heating and oxidization tendency of joint leading to high spatter. When wire feeding speed is matched with welding velocity,microstructure of the joint is composed of fine white ferrite and black pearlite as well as a little uniformly distributed bainite. However,ferrite exhibits coarse bulky structure due to high heat-input with increasing in wire feeding speed. The optimized welding parameters for Q345 steel plate with 12 mm in thickness are presented as follows: current of 160 A,voltage of 22 V,feeding wire speed of 60 m/h,welding velocity of 3 6 mm/s and gas flow of 18 L/min,where hardness of the joint is distributed uniformly with good ductility.关键词：Automatic CO2 Gas Shielded Arc Welding;Q345 Steel;Welding Process Parameters
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发布时间：2023-12-18 - 摘要：The hot tensile deformation of Nitinol 60 shape memory alloy was conducted with Gleeble-3500 thermal simulation machine at 650 850 ℃ and 0. 01 1 s-1. The processing maps were constructed and hot working parameters were optimized based on the generated processing map. The results show that there exists a single unstable region at 650 776 ℃ 、0. 075 1 s-1associated with flow localization in the processing map. The optimized hot working conditions correspond to 690 750 ℃ 、0. 01 0. 026 4 s-1with peak efficiency of 0. 35 at 720℃ 、0. 01 s-1,and 750 838 ℃、0. 01 0. 050 5 s-1with peak efficiency of 0. 38 at 810 ℃ 、0. 01 s-1. microstructural observation indicates that the main deformation mechanism of optimized domains is characterized by dynamic recrystallization.关键词：Nitinol 60 Shape Memory Alloy;Processing Map;High Temperature Deformation Characteristic
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发布时间：2023-12-18 - 摘要：Through using A357 alloy and Si C micro powder as raw material,SiCp/A357 composites with 20%SiCpparticles were prepared with different technological parameters of mechanical stirring casting using doubledeck impeller. The effects of technological parameters on the uniformity of SiCpin the composites prepared were investigated. The SiCp/A357 composites were treated by T6 treatment to analyze the influence of heat treatment on microstructure and mechanical properties of the composites by SEM,Brinell hardness and tensile test. The results reveal that the uniform distribution of SiCpusing double-deck impeller can be observed at 800 r/min for 30 min and 610 ℃. After T6 heat treatment,the tensile strength and hardness of the composites reach 345 MPa and123. 3 HB,increased by 66% and 48. 6%,respectively,compared with those of as-cast ones. The fracture analysis reveals that the fracture mechanism of the composites is characterized by a mixed modes including interface decohesion between A357 and SiCp,SiCpfracture and ductile fracture of A357 matrix.关键词：SiCp/A357 Composites;Stirring Casting;Microstructure;Mechanical Properties;Heat Treatment
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发布时间：2023-12-18 - 摘要：According to the structural characteristics of the aluminum outer sleeve of the water-cooled end cover of locomotive motor,the casting process was designed and optimized. Numerical simulation results show that through setting the appropriate annular riser,blind risers and cold iron in the hot spot of the castings,the problem of shrinkage porosity in castings was improved effectively. Then the casting process was optimized. When the annular riser height was reduced to 90 mm,and the blind riser height was reduced to 80 mm,the process yield of castings reaches 51. 6%,improved by 14. 2% compared with that of un-optimized ones. The optimized casting process was applied to practical production with desirable quality.关键词：Water-cooled End Cover;Aluminum Outer Sleeve;Casting Process;Numerical Simulation
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发布时间：2023-12-18 - 摘要：<正>5月初,伊之密HPM4500T压铸机正式出机。这是伊之密和HPM有史以来联合设计生产的最大吨位压铸机,从图纸设计、零件采购到装配、验收,历时16个月。预计将在6月中旬交付北美知名汽配企业Walker Die Casting。据了解,HPM4500T压铸机完全按照美国标准打造,延续HPM II系列压铸机特色,采用高标准高刚性的用料和设计,以及多泵站独立控制。为了保证机器达到美国标准,伊
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发布时间：2023-12-18 -
- 摘要：<正>2017年15月,国内外铝价在中国电解铝供给侧改革以及全球铝市供需关系改善预期等因素带动下,总体呈现高位震荡格局。尽管铝在此期间成为市场相对抗跌的商品之一,但随着行业经营状况不断改善,市场潜在供应风险却有所增加;与此同时,国内外复杂多变的宏观经济形势等因素,也给年内铝消费增长带来一定变数。
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发布时间：2023-12-18 - 摘要：<正>2017年4月,中国铝合金车轮出口额3.52亿美元,同比增加12.1%,出口量7.61万吨,同比增加13.9%,出口单价4.63美元/公斤。2017年14月底中国铝合金车轮出口额13.25亿美元,同比增加12.7%,出口量28.95万吨,同比增加14.7%,出口单价4.58美元/kg,出口厂商750家,其中前40位厂商出口总金额11.16亿美元,占该产
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发布时间：2023-12-18 - 摘要：<正>位于青海西宁市经济开发区的青海盐湖特立镁有限公司（简称"特立镁公司"）镁合金压铸生产基地已建成投产。特立镁公司为青海盐湖工业股份有限公司（简称"盐湖集团"）全资子公司,设计年产能4 000 t镁合金压铸件。据悉,盐湖集团是中国最大的钾肥工业生产基地。公司在青海盐湖设立镁合金压铸生产基地,是充分利用青海盐湖丰富的镁资源优势,作为公司产业链的重要延伸,布局
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发布时间：2023-12-18 -
- 摘要：Aiming at the trend of large and long life blast furnace,it was described for application history and current application status at home and abroad,the advantages and the manufacturing process. Meanwhile,the main damage accidents of copper cooling staves since 2010 were summarized and analyzed,and affecting factors such as trace elements content in copper,the hydrogen embrittlement of copper and the stability of adherent dross were discussed. Finally,the problems and future of cooper cooling stave were presented.关键词：Copper Cooling Staves;Blast Furnace;Hydrogen Embrittlement;Heat Transfer Model
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发布时间：2023-12-18 - 摘要：A two-dimentional finite element model of aluminum alloy die casting die for joint was established by using Pro CAST software. Equivalent plastic strain and thermal fatigue of die casting die under the heat balance condition were analyzed. Orthogonal experiment of three factors and three levels was designed with the fatigue life as the experimental goal. The results show that the order of the factors affecting the service life is presented as follows: die preheating temperature,pouring temperature and heat transfer coefficient of release agent. Die casting die has the desirable service life at the pouring temperature of 600 ℃,die preheating temperature of 250 ℃ and heat transfer coefficient of release agent of 400 W/（m2·K）.关键词：Die Casting Die;ProCAST Software;Orthogonal Experimental;Service Life
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发布时间：2023-12-18 - 摘要：The hot deformation behaviors of low carbon steel QD08 were investigated by hot compression tests at temperatures from 1 000 to 1 200 ℃ and strain rates from 0. 1 to 10 s-1. In order to describe the flow characteristics,a constitutive equation was established. Based on dynamic materials model and Prasad’s instability criterion,the power dissipation map and the instability map were drawn. The processing map was obtained by superimposition of the power dissipation and the instability maps as well as the regions having the lowest strain rate sensitivity added for more clarification of low and high workability regions. The microstructure of the low carbon steel QD08 was analyzed to correlate with the processing maps. The results show that the safe domain of hot deformation for low carbon steel QD08 is mainly at the temperature range in 1 070 ～1 100 ℃,and strain rate range of around 5～10 s-1. By the metallographic observations,the grain is refiend by DRX under the stable deformation conditions.关键词：Low Carbon Steel QD08;Constitutive Equation;Processing Map;Dynamic Recrystalliza tion
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发布时间：2023-12-18 - 摘要：The recognition of aluminum alloy wheel hub is an important part of the intelligent production management platform. Based on the powerful machine vision open source library of the OpenCV,the Microsoft Visual Studio platform and MFC was used to build the system interface which provided the real-time photographs of wheel hubs. The shapes of the rough castings with a larger burrs were polygonally simplified and their features were extracted. Then the order number of the images was generated to match and classify the wheel hub images to finally conduct the real-time classification. The system can improve effectively the production efficiency,and realize the intelligent hub classification and data transmission.关键词：Aluminum Alloy Wheel Hub;OpenCV;Identification and Classification
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发布时间：2023-12-18 - 摘要：The compression experiments of semi-solid ZCu Sn10 copper alloy billets were performed by using the Gleeble-1500 thermal mechanical simulator. The effects of compression conditions on the deformation behavior and microstructure evolution of the semi-solid ZCu Sn10 copper alloy billets were investigated. The experimental results reveal that the dendrite sample is difficult to be deformed because of its dendrite. The copper alloy with non-dendrite structure has the lower loading compared with the as-cast samples. The load-displacement curves are affected by temperature seriously. The load is increased with the increase of displacement,and the higher temperature leads to the higher liquid fraction and the lower loading,while the higher deformation rate leads to the higher loading under the same displacement. The microstructure is changed continuously during compression process. Within a certain range,a higher compression rate and temperature are beneficial for the collaborative flow of solid and liquid phase.关键词：Copper Alloy;Semi-solid;Compression Deformation;Microstructure
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发布时间：2023-12-18 -
Present Development Situation and Prospect of V-process Casting of Aluminum Alloy at Home and Abroad
摘要：The research progress of V-process casting of aluminum alloy casting at home and abroad was reviewed,and the typical aluminum alloy V-process casting applications enterprises and its products were introduced. The quality of aluminum alloy castings was detected by the roughness,hardness and pinhole of the aluminum alloy casting produced by the resin sand,clay sand and V-process casting,which provided a reference for quality of V-process casting of aluminum alloy casting.关键词：V-process Casting;Aluminum Alloy;Quality Inspection- 2
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发布时间：2023-12-18 - 摘要：Effects of Zn content and Si C addition on structure and decomposition behavior of magnesium alloys were investigated by static weight loss,polarization curve and the micro-morphology characterization. The results indicate that the content and distribution of Mg7Zn3 in Mg-12Zn-0. 6Zr and SiCp/Mg-12Zn-0. 6Zr are different from Mg-8Zn-0. 6Zr. By increasing Zn content and Si C addition,decomposition rate of three magnesium alloy is increased from 2. 30 to 5. 62,7. 24 mg·cm-2·h-1,respectively. The compressive strength of the alloy is decreased linearly with the weight loss of the magnesium alloy during the degradation process,which is attributed to the anode dissolution of α-Mg matrix,the detachment of tiny particles and the no negative effect on degradation process of degradation products.关键词：Degradation Materials;Magnesium Alloy;Zn;SiCp;Microstructure and Properties
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发布时间：2023-12-18 - 摘要：14% SiCw（ in volumetric fraction）/Al composites were fabricated by squeeze casting method. The effects of aging treatment and annealing treatment on microstructure and properties of 14% SiCw/Al composites were investigated by optical microscopy,SEM and tensile testng. Microstructurd observation reveals that Si C whiskers are distributed uniformly in the composites with absence of casting defects,such as holes and porosities.The tensile strength of the composites can be improved after heat treatment,and the tensile strength reaches 321.4 MPa and 392. 7 MPa after annealing treatment and T6 treatment,which are increased by 52. 9% and 86. 8%,compared with those of the as-cast ones,respectively. A high strength aluminum matrix composites with low reinforcement content can be fabricated by squeeze casting method.关键词：Metal Matrix Composites;Squeeze Casting;T6 Heat Treatment
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发布时间：2023-12-18 - 摘要：Auto filter system and condensate system assembly is redesigned which is composed of an oil filter,a water pump and a water cooler. The product has complex structure and high requirement of die casting process.Development of the mold and the products is extremely difficult. Many problems and defects in the product development process are solved to ensure the success of the project by high vacuum die casting technology,automatic electric spraying technology,high pressure cooling intelligent control technology and improvement of product’s chemical composition. It provides technical support for the improvement of the relevant structure of many automobile parts.关键词：High Vacuum Die Casting;Electric Spraying;High Pressure Cooling Intelligent
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发布时间：2023-12-18 - 摘要：According to the shrinkage porosity and slag defects in the end cap,the original casting process was analyzed,and the process was optimized. The results show that the optimized gating system can eliminate effectively the defects of shrinkage porosity and slag inclusion,greatly improving the qualified rate of castings.关键词：Investment Casting;Shrinkge Holes;Inclusion;Gating System
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发布时间：2023-12-18 - 摘要：The frame and tank cover that made of ZL114 A alloy were chosen as the experiment object,and the mathematical relationship between theory size of casting and wax model size after 3D printing was built up by testing solidification size of wax model,investment mold and ZL114 A alloy,which realized the dimensional accuracy control from CT6 to CT7. The average tensile strength,yield strength and elongation of ZL114 A frame and tank cover castings reach 341 MPa,263 MPa and 6. 1%,respectively,by adopting low pressure casting. In addition,the fracture mechanism is characterized by a typical dimple crack.关键词：3D Printing;ZL114A Alloy;Solidification Shrinkage;Investment Casting
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发布时间：2023-12-18 - 摘要：<正>锂电池目前已获得广泛应用,但其具有明显的缺点,一是含锂的材料来源有限,二是目前锂电池中使用可燃的液态电解液,易燃易爆,安全风险较大。在瑞士国家科研基金会的支持下,瑞士联邦材料研究所、日内瓦大学、保罗谢尔研究所自2015年起联合展开了一项科研项目,尝试用钠镁材料替代锂开发蓄电池,取得阶段性成果。
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发布时间：2023-12-18 - 摘要：<正>由于波音公司正在努力降低787梦幻客机的成本,3D打印钛零件可能是其中的一部分。挪威3D打印公司Norsk Titanium AS满足了波音公司对3D打印件的需求。通过FAA最近批准的一个打印过程,零件制造协作可以降低梦幻客机的成本,每架飞机节省多达300万美元。一架波音787中可以使用RPD工艺制造的钛组件估计有1000个。"我们认为每个零件可以节省2500美元,每架飞机就是
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发布时间：2023-12-18 - 摘要：Through using water-atomized copper powder as matrix,adding SiC particles as particle reinforcement and iron as strengthening component,graphite as lubricant,SiCp/Cu composites were fabricated by the hotpressed sintered technology and powder metallurgy method. The friction and wear properties of the composites were investigated on MRH-3 tester at room temperature. The influence of SiC content on the mechanical properties and wear resistance of the composites prepared were expounded. The results reveal that the mechanical properties and wear resistance of the composites are superior greatly to those of oxygen free copper. The relative density of the composites is decreased gradually with increase of the porosity. In addition,hardness,bending strength and wear resistance of the composites are increased firstly and then decreased. The desirable compreshensive performance can be obtained with 7. 5% SiCp in the composites. The wear mechanism is characterized by abrasive wear and adhesive wear.关键词：SiCp/Cu Composite;Powder Metallurgy;Hot-pressed Sintered Technology
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发布时间：2023-12-18 - 摘要：With the addition of nano-TiB2,Ti-46Al-xTiB2（ x = 0,0. 5,1. 0,1. 5,in volume fraction） was prepared by planetary ball combined with SPS sintering method. The mechanical properties,microstructure and ambient compressive behavior of the alloy prepared were investigated. The results show that Ti Al alloy exhibits the relatively excellent mechanical properties,such as tensile strength of 1 543 MPa and elongation of 19. 4% with0. 5% TiB2,which are increased by 71. 2% and 37. 5%,compared with those of Ti-6Al alloy,respectively. It is attributed to the refinement effects of nano-TiB2 particle on the Ti Al alloy. However,with the increase of TiB2,the nano-TiB2 exhibits more and more serious segregation in grain boundary,which in turn deteriorates the mechanical propertie as a result of cutting effects on the matrix.关键词：Nano-Sized TiB2;TiAl Composites;Ambient Compression;Spark Plasma Sintering
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发布时间：2023-12-18 - 摘要：The wettability and metallurgical bonding between molten Mg and Al substrates can be improved by using the brazing flux QJ207 to remove the oxide film on the surface of Al substrates. The as-prepared Mg-Al bimetallic samples with varied Si contents can be produced via adjusting the Si contents in Al substrates. The microstructure and mechanical properties of the AM60/Al Si alloy were investigated by SEM,EDS,XRD and tensile testing. The results reveal that Mg2Si can be generated in the transition layer with the increase of Si content in Al substrate. When the Si content reaches 5. 5%,the Mg2Si particles are connected with each other to form a Mg2Si layer,and Mg2Si layer is tended to the interface with Si content increase. With Si content of 12. 5%,the Mg2Si layer is transfered to the interfacial surface to inhibit the generation of the intermetallics and the brittle phases in the transition layer effectively,so mechanical properties of the composites prepared are improved.关键词：Mg-Al Bimetallic;Brazing Flux QJ207;Si Content;Mg2Si Layer
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发布时间：2023-12-18 - 摘要：The effects of welding current on microstructure and mechanical properties of the welded joint of 6008-T66 aluminum alloy/H220 YD steel were investigated,and mechanism of the fracture behavior of dissimilar metal welded joints was enpound. The results show that with the welding current increasing from 18 k A to 22 k A,the nugget diameter and indentation rate exhibit a rapidly increasing trend,however,with the welding current more than 22 k A,the nugget diameter remains stable or increased slightly,while the indentation ratio is increased gradually. The thickness of intermetallic layer in the interface of aluminum/steel welded joint is increased with the increase of welding current,and the thickness reaches 7. 1 μm when the welding current is 25 k A. With the increase of welding current,the tensile shearing force of 6008-T66 aluminum alloy/H220 YD welded joint is increased firstly and then decreased,and the maximum value can be obtained when the welding current is 22 k A. When the welding current is 22 k A,the tensile shear specimen is broken at the nugget with the button breaking mode,and the welding current is too high or too low,the tensile shear specimen is cracked at the interface.关键词：Welding Current;Al/Steel Dissimilar Metal;Intermetallic Compound;Tensile Shearing Force
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发布时间：2023-12-18 - 摘要：The as-cast Mg-6Li-3Al-1Zn（ LAZ631） alloy was hot-rolled,and microstructure and tensile properties of the hot rolled plates were investigated by using OM,XRD and uniaxial tensile testing. The results show that the large deformation can be achieved by the hot rolling of LAZ631 alloy. With the increase of rolling deformation,microstructure of the alloy is refined. At a higher rolling temperature,parts of the Al Li phase can be re-dissolved into the matrix and the α phase is generated at the（ 0002） preferred orientation. The β phase is distributed in α phase with continuous tiny-line shape under the severe deformation. The tensile strength of the alloy is increased with increasing in the rolling temperature and the deformation as a result of the working hardening and microstructure refinement,and the maximum value reaches 312. 73 MPa. At a higher temperature,elongation of the hot-rolled alloy is decreased with the increase of the deformation,while at a lower temperature,the elongation is increased firstly and then decreased with increasing in the deformation rate,which can be attributed to the recrystallization of the alloy.关键词：Mg-Li Alloy;Hot Rolling;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The heat treatment of medium strength aluminum alloy was investigated. Through adjusting processing procedures,quality of the product and the production efficiency were improved,and product cost was decreased.Effects of different heat treatment on performance of medium strength aluminum alloy wire were analyzed comparatively to determine the feasibility of heat treatment. The results reveal that through adjusting procedures to reduce process procedures,the tensile strength,elongation and electric conductivity of the wire can be improved.The practical production exhibits that the qualified rate of the wire is 100%.关键词：Heat Treatment;Medium Strength Aluminum Alloy Rod;Mg2Si;AA6101
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发布时间：2023-12-18 - 摘要：The effects of different deformation conditions on the superplasticity of TB8 alloy and the microstructure evolution during deformation process were investigated. The results reveal that at 720 ～ 840 ℃ and 1. 0 × 10-4～1. 0 × 10-3s-1,TB8 alloy exhibits the superplastic behavior. At 750 ℃ and 1. 0 × 10-4s-1,elongation of the TB8 alloy reaches 524. 9%. During deformation process,the working hardening and the softening exhibits balance,and the alloy is characterized by the traditional steady-state superplastic flow behavior. Meanwhile,the deformation temperature,strain-rate and deformation rate have the significant effects on the microstructure. With decreasing in strain rate or increasing in tensile temperature,the size of the equiaxed β phase is increased.While with increasing in deformation temperature,α phase is dissolved into the matrix gradually and β phase tends to be saturated,however,the grains still retain in equiaxed state to some extent. The α phase segregated dispersedly from the grain boundary and matrix of β phase is increased with the deformation rate increase,which can inhibit the growth of grain size and improve the plasticity.关键词：TB8 Titanium Alloy;Superplasticity;Microstructure;High Temperature Tensile Testing
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发布时间：2023-12-18 - 摘要：The effects of Al-4P modification on microstructure and machinability of hypereutectic Al-20 Si alloy were investigated by orthogonal experiment,and the process parameters of improving hypereutectic Al-20 Si alloy machinability were optimized. The results show that the added amount of Al-4P is the most significant impact on the primary silicon,then the modification time,modification temperature. The optimized process parameters of improving the Al-20 Si alloy machinability were presented as follows: the addition of Al-4P of 1% at 760 ℃ for 1h. After modification treatment,the primary silicon becomes small with dispersed and round passivation,and the average size is reduce from 120 μm to 30 μm,so the tool life is increased and the machinability is improved.关键词：Hypereutectic Al-20Si Alloy;Microstructure;Machinability;Tool Life
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发布时间：2023-12-18 - 摘要：The effects of aging temperature and aging time on microstructure evolution and mechanical properties of Ti-6Al-2.5V-1.5Fe-0.15 O alloy prepared by high vacuum non consumable arc furnace were investigated after solid solution treatment and air cooling. The results reveal that with a lower aging temperature,nuclear energy ofα is low,leading to diffusion diffuculy of elements,so α nucleation needs the aid of dispersed ω phase,which results in the small and dispersed needle-like α phase. With increasing in aging temperature,driven force of nucleation and growth of α phase are increased,resulting in easy to be grown up of aging phase. With increasing in aging time,the aging α phase is coarsened,and the aging region is increased. After aging treatment,α phase is responsible for the increase of alloy strength. As the aging time increase,the yield strength and the peak strength are decreased,while the fracture strain is increased.关键词：Ti Alloy;Aging Treatment;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The effects of Pr on the microstructure of as cast,solid solution and aging Al-5Cu alloy,as well as aging state on micro hardness and mechanical properties at room temperature and high temperature were investigated by OM,SEM and TEM,and the existing forms and mechanism of Pr were analyzed. The results show that Pr can refine effectively the α-Al dendrite in Al-5Cu alloy,and the dendrite size is decreased firstly and then increased with the increase of Pr content,and the minimum value can be observed with the Pr content of 0. 3%.The suitable heat treatment of Pr modified Al-5Cu alloy is 540 ℃ × 8 h solid solution + 165 ℃ × 10 h ageing treatment. When the aging temperature is 165 ℃ and 185 ℃ and 250 ℃,the average length of the θ’ phase in Al-5Cu alloy with 0. 3% Pr modification is reduced by 23. 2%,25. 6% and 31. 1%,respectively,compared with unmodified Al-5Cu alloy,and the number of precipitates is significantly more than the alloy without Pr modification. With the increase of Pr content,the tensile strength and elongation are increased at first and then decreased,and the maximum value is obtained when the content of Pr is 0. 3%. Tensile strength and elongation at room temperature and high temperature of the Al-5Cu alloy with 0. 3% Pr modification are higher than unmodified Al-5Cu alloy,and the main mechanism is characterized by fine grain strengthening and second phase strengthening.关键词：Pr;Al-5Cu Alloy;Modification;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：The effects of Cu on microstructure and mechanical properties of rare earth microalloying A356 alloy were investiagted by using Metalloscope,SEM,EDS,XRD and tensile testing machine. The results indicate that Cu has a significant effect on improving the strength of rare earth microalloying A356 alloy. Cu could not only refine primary α-Al phase but also take the transformation from rodlike structure to small round granular Si with diepersedly distributed on the grain boundary of α-Al phase. With 2. 5% Cu addition,the tensile strength,yield strength and elongation of the alloy reach 235 MPa,322 MPa and 4. 6%,respectively,which increased by 10.35%,26. 82% and decreased by 21. 5% compared with those of the alloy without Cu.关键词：Rare Earth Microalloy;A356 Alloy;Microscopic Structure;Mechanical Properties;Cu
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发布时间：2023-12-18 - 摘要：Effects of Cu on microstructure and elevated temperature properties of as-cast Mg-Zn-Y alloy containing icosahedral quasicrystals phase were investigated. The results reveal that,with increasing in Cu content,microstructure of the MgZn6 Y1 alloy can be further refined. However,with Cu content more than 1. 5%（ in atom）,the grain size of alloy is coarsened. The addition of Cu can improve the elevated temperature mechanical properties of MgZn6 Y1 alloy. The tensile strength and elongation of MgZn6 Y1 Cu1.5 alloy reach 153 MPa and10. 6%,compared with those of MgZn6 Y1 alloy,increased by 26. 4% and 49. 3%,respectively. The creep resistance of MgZn6 Y1Cu1.5 alloy is superior to that of MgZn6 Y1 under the same creep conditions.关键词：Copper;Mg-Zn-Y Alloy;Microstructure;Elevated Temperature Mechanical Properties;Creep
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发布时间：2023-12-18 -
First-principles Study on Effects of Alloying Elements on the Phase Stabilities of Laves Phase TaCr2
摘要：The electronic structure and density of states of the C15 Laves phase TaCr2 with the doped alloying elements X（ X = Ru,V and Nb） were investigated by using first-principles calculation. The atomic site occupation and effects of the alloying elements on the phase stability in Laves phase TaCr2 were analyzed. The results show that Ru or V can subsititute the Cr sites preferentially and Nb occupy the Ta sites preferentially in TaCr2. The phase stability of TaCr2 alloys can be reduced by adding Ru or V,while it can be enhanced inversely by adding Nb.关键词：First-principles;Laves Phase TaCr2;Phase Stability;Density of States- 2
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发布时间：2023-12-18 - 摘要：The selection of the power spinning parameters has a direct influence on the dimensional precision of the formed products. Through taking the tin-bronze connecting rod bushing after power spinning as the object,selecting thinning rate,working angle of wheel,fillet radius of wheel and feed ratio as factors of optimization experiment as well as taking difference of wall thickness and the expanding diameter of connecting rod bushing after spinning as the evaluation indicator,orthogonal experiment was designed and the experiment data was analyzed.The power spinning parameters were optimized through the Taguchi method. And the optimized parameters were presented as follows: the thinning rate of 30%,the working angle of the rotary wheel of 15°,the radius of the rotary wheel of 10 mm,and the feed ratio of 0. 5 mm/r.关键词：Power Spinning;Connecting Rod Bushing;Dimensional Precision;Taguchi Method
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发布时间：2023-12-18
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