最新刊期
卷 40 ， 期 8 ， 2020
- 摘要：A composition design of Mg rare earth alloys based on the total solute control was carried out. By screening the elements to inhibit the eutectic phase content in magnesium alloys, the effects of alloy composition on the non-equilibrium solidification structure, solidification interval, fluidity and crack resistance of the cast magnesium alloy were investigated, and the heat treatment process was optimized. The results reveal that the large and complex structural parts prepared with Mg-5.8 Gd-3.0 Y-0.4 Zr under the slow cooling conditions of sand mold present excellent mechanical properties, where mechanical properties reach more than 300 MPa in tensile strength, more than 220 MPa in yield strength, and more than 3% in elongation, meeting the requirements for comprehensive strength and toughness of large and complex structures with heavy loads and overloads.关键词：Sand Mold Casting;Divorced Eutectic;Casting Formability;Rare Earth Magnesium Alloy
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发布时间：2023-12-18 - 摘要：Effects of ageing temperature on the microstructure and properties of in situ hybrid Ti-6 Al-4 V composites with TiB and TiC reinforcements were investigated. The results show that, with the increase of 673～873 K aging temperature, the martensite formed during solid solution treatment is decomposed gradually and transform to β phase with dispersive distribution and α phase. When the aging temperature is higher than 823 K, the β phase is coarsened. The mechanical properties of the composites aged at 773 K present the acceptable data, where the compressive strength, yield strength and engineering strain reach 1 970 MPa, 1 632 MPa and 15.2%, respectively. The Vickers hardness of the composites is decreased with the increase of aging temperature. With the increase of wear loads, the friction coefficient of the composites is decreased and the wear loss is increased gradually. The wear mechanism under low load is characterized by abrasive wear, while the wear mechanism is characterized by co-action of abrasive wear and oxidation wear with the load of 50 N.关键词：Ti Matrix Composite;Aging Temperature;Compressive Performance;Friction Coefficient;Wear Loss
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发布时间：2023-12-18 - 摘要：<正>美国德克萨斯大学奥斯汀分校研究人员开发出一种可在室温下工作的新型液态金属电池,创下了目前液态金属电池的最低工作温度记录。研究人员在《先进材料》杂志上发表论文称,这种电池兼具固态金属电池和液态金属电池的所有优点,拥有广阔的应用前景。液态金属电池被认为是用于固定式储能的很有前途的电化学系统。当前,所有报告的液态金属电池都需要在高于240 ℃的温度下工作,以使金属电极保持在熔融状态。而该研究团队开发的液态金属电池,其金属电极可以在20 ℃
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发布时间：2023-12-18 - 摘要：<正>电动飞机技术是一项跨时代的新技术,它和新能源电动汽车有着相同的发展轨迹,已成为世界航空工业发展的核心技术之一,它改变了传统的飞机设计理念,从飞机绿色环保、高效节能、智能互联的理念出发,来优化整个飞机的设计,在很大程度上提高了飞机的可靠性、实用性、环保性、舒适性和可维护性,是未来飞机的发展方向。电动飞机技术发展的核心是电力推进技术。当今电力推进技术的进步非常快,飞机燃油的能量密度约为12.7 kWh/kg,而目前电池能量密度最大也只能
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发布时间：2023-12-18 - 摘要：<正>据特斯拉首席执行官埃隆·马斯克透露,特斯拉备受期待的跑车最早将于明年在加州弗里蒙特的超级工厂投产。在讨论为不断增长的电动汽车车队扩大生产设施的计划时,马斯克提到了特斯拉跑车,指出未来的项目将在加州进行。特斯拉跑车的生产可能会在该公司位于加利福尼亚州弗里蒙特的主要工厂进行。特斯拉已经向当地政府机构提交了多项申请,要求开始开发General Assembly 4.5,也就是Model Y车型的生产地。该公司还计划通过在工厂再增加一台超大
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发布时间：2023-12-18 - 摘要：<正>日前,加拿大联合镁业公司（Alliance Magnesium）开建高附加值的镁锭生产厂。新工厂位于加拿大魁北克省岩棉市,其中铸造中心将首先投入运营,并将在2021年第一季度开始镁回收熔炼业务。联合镁业表示,镁的需求呈不断增长的走势,需求量从20年前的30万t增加到目前的100多万t。在汽车和航空航天领域,镁用量的增长最为明显。在这些领域,镁是减轻车辆质量和实现运输电气化的理想材料。这些领域面临着减少车辆和设备质量以降低温室气体排放
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发布时间：2023-12-18 - 摘要：<正>国际铝业协会秘书长Miles Prosser表示,2020年全球铝需求预计将比2019年下降5.4%,由于2020年迄今为止的产量有所增加,可能将导致Al库存。不过,Prosser在接受标普全球普氏能源资讯采访时援引CMGroup的信息称,中期需求将强劲增长,因政府投资基础设施、建筑和汽车行业,以加速冠状病毒大流行后的经济复苏。他指出,2020年到目前为止原铝产量有所增加,部分原因是冶炼炉依赖于稳定的电力供应,很难关闭。国际
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发布时间：2023-12-18 - 摘要：<正>据外媒报道,由英国克兰菲尔德大学可持续性制造系统中心进行一项新研究,比较了3种不同的合金（铝-A380、镁-AZ91D和锌-ZA8）。研究表明,在生产汽车零部件时,用锌合金取代铝合金可以极大地延长部件的寿命,还可以提高可持续性。该项研究指出,人们总是优先选择铝的原因在于,没有充分考虑到最终产品的可持续性。当把时间、成本和灵活性等传统因素与可持续性因素结合考察时,克兰菲尔德大学的研究表明,对于汽车制造商而言,锌与铝或镁合金相比,而且更
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发布时间：2023-12-18 - 摘要：Uranium molybdenum alloy flywheel with 1.1 m in external diameter and 1 t in weight was produced by vacuum centrifugal casting. It is found that the composition and grain size are uniform at different positions of the casting after heat treatment. The Mo content is in range of 2.00% to 2.08%, and the grain size is in range of 53 μm to 73 μm. The impurity content in flywheel is low, and the size of the carbide inclusions is small with dispersed distribution. Comparing the mechanical properties at different flywheel locations, it is determined that all the tensile strength, impact toughness and fracture toughness can reach above 800 MPa, 35 J·cm-2 and 70 MPa·m1/2, respectively.关键词：Uranium Molybdenum Alloy;Centrifugal Casting;Flywheel;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：In order to evaluate the microstructure and performance of large-scale complex titanium alloy castings and other aircraft critical structural components, the structural uniformity of a titanium alloy mainframe casting was analyzed. By analyzing the distribution of the various regions of the casting and the presence of anomalous grains, the key factors affecting the casting microstructure were described, and the microstructure homogeneity of a titanium alloy mainframe casting was evaluated. The results show that the grain size in the castings is in range of 44 μm to 7 660 μm, and the sizes of 82% of the grains are within 1 650 μm. As the thickness of the casting increases, the average grain size and the FWHM of the surface layer and the center layer of the casting show a nearly logarithmic increased trend. The factors such as wall thickness, structural characteristics and pouring sequence of the castings all have an important influence on solidification, of which the wall thickness has the most significant effect.关键词：Titanium Alloy Castings;Microstructure;Distribution;Aircraft Engine
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发布时间：2023-12-18 - 摘要：In order to reduce the degradation rate of magnesium alloy stents, magnesium fluoride coating was prepared on the surface of magnesium alloy by chemical conversion. The effects of hydrofluoric acid concentration and treatment time on the composition, brittleness and corrosion resistance of the coatings were investigated. The results indicate that the thickness of magnesium fluoride coating is increased with the treatment time, while the brittleness is also increased. In addition, the brittleness of the coating in a higher hydrofluoric acid concentration are lower, so the corrosion resistance presents better. The coating presents the satisfied comprehensive performance with hydrofluoric acid concentration of 40% at treatment of 6 h.关键词：Coronary Stents;Magnesium Alloy;Magnesium Fluoride Coating;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：Developing the "low cost, short process" manipulation technology is the future developing trend of Chinese titanium industry centered on electron beam cold hearth smelting（EBCHM） for high performance titanium materials. In order to reveal the complex physical phenomena in the process of EBCHM and establish the mechanism for controlling products quality, the multi physical numerical model, which is an effective tool for realizing the "visualization" of high temperature smelting process, was widely concerned. The development of the numerical model of EBCHM was reviewed, and the theoretical support of the existing numerical model for the investigation of the physical and transfer phenomenon in the smelting process was discussed, and the further developing trend of the multi physical coupling numerical model was proposed.关键词：Multi Physical Coupling Numerical Model;EBCHM;Titanium Alloy;Transfer Phenomenon
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发布时间：2023-12-18 - 摘要：<正>近日,中国船舶七二五所联合中核集团原子能院、合肥通用机械研究院有限公司研制的我国首台液态金属钠-超临界二氧化碳印刷板式换热器（PCHE）完成了试验台架考核,顺利通过专家组验收,产品技术达到国际先进水平。这是七二五所PCHE产品继高效火力发电领域、海洋工程领域、氢能源领域后,在核能领域实现的又一个新突破。钠-超临界二氧化碳换热器是第四代核能—液态金属冷却快堆革新型动力转换系统的关键设备之一,需在高温高压强腐蚀等苛刻条件下实现高效换热。
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发布时间：2023-12-18 - 摘要：<正>日前,青海省科技厅组织专家对青海盐湖镁业有限公司、青海北辰科技有限公司共同承担的"大型金属镁人工智能化铸造生产线技术研究与应用"项目进行了验收。经专家组评审,项目在镁液浇注时采用R134a、SF6气体自动保护和智能铸造系统集成等方面具有创新性,建成了4.4万t/年大型金属镁人工智能化连续铸造线,符合工业化、规模化、现代化、绿色化生产要求,对镁锭连续铸造线的研发制造及推广应用起到示范作用,同意通过验收。
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发布时间：2023-12-18 - 摘要：<正>在2020年国际压铸展期间,台山市中镁科技有限公司与伊之密现场签订合约,订购两台半固态镁合金注射成型机UN650MGII、UN1250MGII和一台冷室压铸机DM3000HARCSM。台山中镁公司总经理唐剑平先生透露,UN650MGII将计划用于生产无人机结构部件,自行车运动部件,UN1250MGII则是针对大型无人机结构件、新能源汽车领域做准备。台山中镁公司位于广东江门台山市,致力为客户提供完整的镁合金产品解决方案,具备镁合金材料
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发布时间：2023-12-18 - 摘要：The machine learning method was applied to predict shrinkage defects in casting process. The targeted pre-processing method was employed to process casting data, and the multi-modal data input method was adopted to increase the data dimension. Fully convolutional networks were used to fast calculate casting shrinkage porosity defects. Based on the fast prediction method, a typical casting was selected for analysis, which verified the effectiveness of the method. Compared with the numerical simulation method, this method has high accuracy, and can greatly reduce the calculation time of casting shrinkage defeets.关键词：Casting Defect;Fully Convolutional Networks;Deep Learning;Multi-modal Numerical Simulation
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发布时间：2023-12-18 - 摘要：The composite material powder was fabricated by physically mixing nano-WC and AlSi10 Mg, and a sample was prepared by using a selective laser melting forming machine. The performance of AlSi10 Mg and composite samples prepared by the same process were analyzed comparatively by optical microscope, scanning electron microscope, tensile test, etc., and the influence of nano-WC on the formation and evolution of microstructure and the influence of the structure on mechanical properties were investigated. The results reveal that composite powder has good sphericity and uniform particle size distribution. The hardness and the yield strength, the tensile strength of the composite sample reach about 158.9 HV and 337.8 MPa, 514.0 MPa, which have increased by 14.6%, 4.73% and 6.3%, respectively, compared with those of the as-deposited ones.关键词：Selected Laser Melting;Nano-WC;AlSi10Mg Alloy;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：In order to reduce the occurrence of die casting cracks and prolong the service life of die casting dies, ordinary hot mold steels and high molybdenum hot mold steels were used to test the modulus of cracks, the mould cycles and depth of crack after nitriding on two surfaces. The residual stress of die during processing was also analyzed. The results show that the die life with surface nitriding treatment can be prolonged by 53%～75% compared with that of one without nitriding treatment at the same product and production conditions.关键词：Die-casting Die;Cracks;Nitriding Treatment
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发布时间：2023-12-18 - 摘要：According to the structural characteristics of the housing shape and hole position of a vehicle gearbox housing, the key design points of gating system, multiple slider and embedded sequential core-pulling mechanism and mold cooling system were analyzed. It can be concluded that the product structure and gating system are closely related with the mold structure, and a reasonable mold structure can not only improve the yield and production efficiency, but also simplify the process flow of die casting die, so as to reduce the mould manufacturing costs.关键词：Gating System;Slide Mechanism;Secondary Core Pulling;Cooling System
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发布时间：2023-12-18 - 摘要：According to the characteristics of large shell diameter, wide range of inner barrel water jacket and uneven wall thickness for housing of electric bus motor, the influence of the complex structure of the water-cooled housing and the barrel-shaped sand core was analyzed on the sequential solidification of aluminum alloy low-pressure casting. Low pressure casting pouring system, mold structure and process parameters were designed. By using the AnyCasting software, the casting solidification process was simulated to predict the isolated liquid phase formed by the hot spot and the sand core separation caused by uneven wall thickness, which lead to defects such as shrinkage and cold shut in some locations. The solidification speed was optimized by adopting beryllium copper inserts, water-cooled inserts and air-cooled pipes to improve the soundness and production quality of the internal structure of the die casting housing.关键词：Low Pressure Casting;Sequential Solidification;Isolated Liquid Phase;Water-cooled Insert;Air-cooled Circuit
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发布时间：2023-12-18 - 摘要：The effects of electromagnetic stirring on microstructures and ring rolling properties of semi continuous casting 2219 aluminium alloy ingot were investigated contrastively. The results reveal that compared with the conventional semi-continuous casting, the solidification structure of semi-continuous casting 2219 aluminum alloy ingot by electromagnetic stirring becomes finer, more uniform and rounder. The overall average grain size is reduced from 546 μm to 186 μm, and the difference ratio of the maximum and minimum grain size is reduced from 19.2% to 3.8%. After the ring rolling deformation, the properties of 2219 aluminum alloy ring rolled with electromagnetic stirring ingot are significantly enhanced. The mechanical properties of the alloy reach more than 460 MPa and 11% in tensile strength and the elongation of high direction, transverse direction and radial direction, and the consistency of properties in different positions and directions is improved significantly.关键词：Electromagnetic Stirring;2219 Aluminium Alloy;Grain Refinement;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The thin-walled impeller of 1.4462 duplex stainless steel was produced. The key procedures were designed strictly to control product quality, such as mold design, injection wax, gating system design, shell making, melting and other key processes. The practical production shows that the quality can meet the customer requirement.关键词：Investment Casting;Duplex Stainless Steel;Fission Mold;Casting Simulation
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发布时间：2023-12-18 - 摘要：With different additives mixed into investment gypsum casting powder, the effects of different additives on the fluidity, solidified time and baked strength of investment gypsum casting powder were investigated. The results show that the polycarboxylic acid water reducing agent has severely retarded the gypsum casting powder slurry, although enhancing the fluidity of the gypsum casting powder slurry, and the 0.1% content is more suitable for gypsum casting powder. When less silica sol is added to the water and the ratio of water to silica sol is less than 1∶1, the silica sol can promote the fluidity of the gypsum casting powder slurry, appropriately increasing the solidified time, and increasing the strength of the gypsum casting mold. When the ratio of water to silica sol is 4∶1, the fluidity of the gypsum casting powder slurry is satisfied. When the water: silica sol is 1∶1, the strength of the gypsum mold is desirable.关键词：Additives;Fluidity;Solidified Time;Baking Strength;Gysum Mold
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发布时间：2023-12-18 - 摘要：Pipe jacking belongs to thin-walled extension pipe, and its casting blank has a great influence on the quality of finished products.The technological process of micro pipe jacking production was described by vacuum EPC with help of the current domestic equipment, and the origination of the defects such as slag inclusion and inclusion in micro pipe jacking during the production process was analyzed in detail. The prevention and control measures were put forward. The process scheme was designed through the equipment upgrading and the optimization of the gating system. By means of continuous improvement and trial production, the satisfied effect could be realized.关键词：Lost Foam Casting;Micro Pipe Jacking;Shrinkage Porosities
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发布时间：2023-12-18 - 摘要：Preparation of foamed magnesium alloy with dolomite as foaming agent and thickener was carried out. The effects of dolomite amount, particle size and adding temperature on structure of foamed magnesium alloy were investigated. The results reveal that dolomite can be used as foaming agent and thickener to prepare foamed magnesium alloy with uniform pore structure and high porosity. However, it has the defects of gas cavity and pore-free layer at the bottom. The minimum density of magnesium foam is 0.38 g/cm3, and the maximum porosity is 78.7%. Dolomite is decomposed in large quantities when heated above 650 ℃, which can be used as foaming agent of magnesium foam. As thickener and foaming agent, dolomite cann’t be decomposed completely, and its residues and decomposition products are basically distributed evenly in the matrix and locally agglomerated at the edge of the hole. The density of foamed magnesium alloy is decreased with the increase of dolomite content in the range of 1%～2.5%. The density of foamed magnesium alloy is decreased at first and then increased with the increase of the size of foaming agent in range of 74～250 μm, and the turning point is 150 μm. In range of 620～710 ℃, as the temperature of dolomite increases, the density of the foamed magnesium alloy is decreased firstly and then increased. The turning point is 680 ℃. The change of porosity of foam magnesium alloy is the opposite to that of density.关键词：Dolomite;Foamed Magnesium Alloy;Structure;Density
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发布时间：2023-12-18 - 摘要：Al0.8CrFe2Nix high-entropy alloys（x denotes the atomic content of Ni element when the atomic content of Al, Cr and Fe is 0.8, 1 and 2, respectively） were prepared by vacuum arc melting. The effects of Ni content on microstructures and mechanical properties of the alloy were investigated by using optical microscope, X-ray diffraction（XRD）, micro-hardness testing and compression testing. The results show that the alloy with dendritic+cellular crystal morphology has a B2+BCC crystal structure when x=0.50. When x=1.25, the crystal structure is transformed to single BCC with a single dendritic morphology. When x=2.00, the crystal structure is changed into a mixed structure of FCC+BCC with a dense lamellar eutectic-like morphology. With the further increase of Ni content, the alloy maintains FCC+BCC structure when x=2.75. However, the proportion of FCC phase is dramatically increased and complete dendritic morphology appears. The hardness of Al0.8CrFe2Nix high entropy alloys is decreased with the increase of x. Meanwhile, the yield strength is decreased and the strain is increased.关键词：High Entropy Alloy;Nickel;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Nano-sized α-Al2O3/Al composite was prepared in situ by exothermic dispersion method using the mixed powder of Al-nano-SiO2. The microstructure and reaction mechanism of the composite were investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, differential scanning calorimetry（DSC） methods, and energy spectrometer（EDS）. The results reveal that Al-nano-SiO2 can react completely to form nano-sized Al2O3 and Si at 900 ℃ for 30 min, in which the volume fraction of the reinforcement can reach 7% with evenly distributed on the aluminum matrix. The corresponding activation energy is increased with the reaction process, indicating that the reaction of Al-nano-SiO2 system can be completed only when sufficient energy is provided in the final reaction stage.关键词：Al-nano-SiO2 System;Microstructure;Reaction Mechanism;Activation Energy
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发布时间：2023-12-18 - 摘要：The Cf/Al laminated composites were prepared by vacuum hot-pressing with 1060 Al foil, HL403 aluminum alloy powder and M40 unidirectional carbon fiber cloth as raw materials, and the fiber volume fraction is 22.80%. The effects of hot-pressing temperature, time and pressure on the microstructure and mechanical properties of the composites were investigated by orthogonal experiment. The results reveal that the hot-pressing time has the most significant effect on the tensile strength, and the hot-pressing temperature has the most significant effect on the density. The addition of HL403 aluminum alloy powder between 1060 Al foil and M40 unidirectional carbon fiber cloth can reduce the hot-pressing temperature and inhibit the interface reaction. Meanwhile, the Al2Cu phase formed can inhibit the formation of the brittle phase Al4C3,which improves the mechanical properties of the composites. With the hot-pressing temperature of 510 ℃, the hot-pressing time of 180 min and the hot-pressing pressure of 15 MPa, the matrix and fiber of Cf/Al laminated composites are well bonded, and the aluminum matrix layer and fiber reinforced layer are arranged alternately, and the fiber presents uniform distribution. A large number of fibers are pulled out when the Cf/Al laminated composites are fractured, and the tensile fracture shows the ductile fracture of the aluminum matrix layer and the brittle fracture of the fiber reinforced layer. The composites show the satisfied performance in density of 2.492 g/cm3, relative density of 99.80%, tensile strength of 254.75 MPa and flexural strength of 334.97 MPa.关键词：Vacuum Hot-pressing Method;Hot-pressing Process Parameters;Cf/Al Laminated Composites;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The effects of different hot compression conditions and multiple heat treatments on the microstructure evolution of TC4-DT titanium alloy were analyzed. The results reveal that the primary α phase in the microstructure is gradually decreased, and the acicular martensite precipitated by water quenching is gradually increased with increasing in temperature of hot compression deformation. The interweaving of the basketweave microstructure in the alloy is more uniform and compact after triple heat treatment at relatively low deformation temperatures of 920 ℃ and 950 ℃. The precipitated acicular α phase is more finely as the strain rate increases at the same time. The duplex microstructure is formed at 920 ℃, and the basketweave microstructure is formed at both 940 ℃ and 960 ℃, while acicular α-phase interlaced the basketweave microstructure is better in the latter. When the double temperature is less than 900 ℃, the acicular α-phase precipitated is relatively slender and grows with increasing in temperature. However, the basketweave microstructure is not uniform through observing the overall morphology. It is found that at 920 ℃, the basketweave microstructure formed in the microstructure is more compact, and the more finer acicular α phases are intertwined therein in the microstructure.关键词：TC4-DT Titanium Alloy;Hot Compression;Heat Treatment;Microstructure
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发布时间：2023-12-18 - 摘要：The effects of 0.05% FeBSi amorphous alloy with different inoculation time on the microstructure and mechanical properties of as-cast and heat treated ZL107 were investigated. The results show that the tensile strength and elongation of the ZL107 alloy are increased significantly with the addition of 0.05% FeBSi amorphous alloy. The tensile strength and elongation of ZL107 with inoculation time of 30 min reach 453.41 MPa and 14.2% respectively, which is 24.7% and 65.7% higher than the ZL107 without FeBSi amorphous alloy, respectively. The α-Al and eutectic Si in ZL107 alloy are refined obviously after the addition of 0.05% FeBSi amorphous alloy, which is attributed to grain refinement strengthening and secondary phase strengthening.关键词：Integrated Experimental Design;FeBSi Amorphous Alloy;Inoculation;ZL107 Alloy
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发布时间：2023-12-18 - 摘要：Effects of solidification structure and Mg content on fast heat treatment of A356 were investiagted. The results reveal that eutectic Si morphology in solidification structure of A356 alloy is converted from fibre to spherical structure after modified by Sr, and the grain size of primary α phase is decreased. After 540 ℃×20 min+170 ℃×90 min fast heat treatment, the Mg2Si strengthening phase in microstructure is fully dissolved into matrix, and tensile strength is basically the same as that of the T6 heat treated alloy. With the increase of Mg content, the solid time required for Mg2Si phase to fully dissolve into matrix is increased during solution treatment. When the Mg content of the alloy is increased from 0.3% to 0.9%, 540 ℃×40 min+170 ℃×90 min fast heat treatment is required, and the mechanical properties of alloy can be the same as that of the T6 heat treated ones关键词：A356 Alloy;Fast Heat Treatment;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The as-cast microstructure and mechanical properties of AlSi10 MgMn alloy with different rare earth（La, Ce） contents were investigated by means of optical microscope, SEM, Vickers hardness and tensile test at room temperature. The results show that rare earth（La, Ce） can refine α-Al, eutectic silicon, AlMnSi and Mg2Si phases in the alloy, and eliminate β-AlFeSi phase. When the content of added rare earth（La, Ce） is 0.1%,the hardness, tensile strength and yield strength of the alloy reach 82.76 HV、373.05 MPa and 281.37 MPa, respectively,which are 12.95%、17.29% and 43.44% higher than those of ones without rare earth, while the elongation is reduced to 2.26%, decreased by 11.37%. Furthermore, the addition of rare earth（La, Ce） has little effect on the fracture mode of the alloy.关键词：AlSi10MgMn Alloy;Rare Earth（La,Ce）;Microstructures;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The effects of single Sr or B content and Sr-B compound addition were analyzed on microstructure and thermal and electric conductivity of ADC12 alloy for LED radiator. The results reveal that with the addition of 0.04% B, the α-Al grains in ADC12 can be refined, thus improving the hardness of the alloy, however, its electrical and thermal conductivity can be weaken to some extent. With adding 0.04% Sr, the size of eutectic silicon and the secondary dendrite arm spacing in the ADC12 alloy are decreased to a certain extent, and its performances are enhanced compared with those of the original alloy. With compound addition of 0.04% Sr and 0.04% B, the modification effect of eutectic silicon in the ADC12 alloy can be improved and the secondary dendrite arm spacing reaches the smallest values. The eutectic silicon is converted from fine fiber shape to short rod shape and granular shape, which reduces the electron transport resistance and thus enhances the electrical conductivity and thermal conductivity of the alloy.关键词：ADC12 Alloy;Strontium;Boron;Electrical Conductivity;Thermal Conductivity
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发布时间：2023-12-18 - 摘要：The effects of heat treatment（solution and aging） on the microstructure and mechanical properties of 6063 aluminum alloy were investigated, and the roles of heat treatment process parameters were analyzed. The results show that with the increase of solution time from 15 min to 120 min, the grain size in the 6063 aluminum alloy is coarsened continuously, and the primary phase of Mg2Si in grain boundary and crystal disappears gradually and is dissolved into the matrix, while the effect of solution holding time on α-Al8Fe2Si and β-Al5FeSi phases can be ignored. Meanwhile, the strength and hardness of the alloy are increased firstly and then decreased, while the elongation is decreased firstly and then increased. When the aging temperature is increased from 160 ℃ to 180 ℃, the second phase in 6063 aluminum alloy is increased gradually, while the second phase in 6063 aluminum alloy is coarsened at 200 ℃, so the strength and hardness of 6063 aluminum alloy are increased firstly and then decreased with the increase of aging temperature, and the elongation is decreased firstly and then increased. When the aging holding time is 3 h or less, the amount of secondary phase is declined in 6063 aluminum alloy, while with the aging holding time of 5 hours or more, the number of dispersed second phase will be gradually increased, and obvious coarsening and growth of the second phase will occur when the aging holding time is 12 h or more. The suitable heat treatment process of 6063 aluminum alloy is 535 ℃×60 min+180 ℃×7 h, where the 6063 aluminum alloy has the maximum strength, hardness and higher elongation.关键词：6063 Aluminum Alloy;Heat Treatment;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：Effects of ultrasonic treatment（UST） on the microstructure and mechanical properties of the Mg-3 Y-3.5 Sm-2 Zn alloy were investigated. The results show that when the UST temperature is at 720～680 ℃ and the UST time is at 60～150 s,the microstructure of the alloy is refined firstly and then coarsened with the decrease of the treating temperature or the increase of treating time, and the turning points are 700 ℃ and 90 s, respectively. The highest value of mechanical properties of the alloy can be obtained after UST at 700 ℃ for 90 s. The microstructure refinement of the alloy after UST is attributed to supercooling nucleation caused by the cavitation effect and the effective inclusions nucleation substrates produced by the high-pressure pulse caused by the collapse of cavitation bubbles, alone or in combination.关键词：Magnesium;Ultrasonic Treatment;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Effects of yttrium on the microstructure and high temperature oxidation behavior of arc melted Ti-45 Al-6 Nb alloys were investigated. The results show that the obtained Ti-45 Al-6 Nb alloys with different yttrium are mainly composed of γ+α2 lamellar, B2 precipitate and a small amount of Y2O3. Addition of trace yttrium in the alloy can be ingored for influence on the phase composition of the alloys, however, it can significantly refine α2+γ lamellar structure. High temperature oxidation results show that addition of trace yttrium in Ti-45 Al-6 Nb alloys can significantly improve the oxidation resistance, especially for the alloy with yttrium concentration of 0.3%. The Ti-45 Al-6 Nb-0.3 Y alloy has an oxidation rate constant of 3.26×10-2 mg2/（cm4·h） at 1 000 ℃ in air, which is account for 41.3% and 26.1% of the alloys with yttrium concentrations of 0.1% and 0.9%, respectively, and about 1 order of magnitude lower than that of the alloy without yttrium addition.关键词：Ti-45Al-6Nb Alloy;Y Modification;High Temperature Oxidation;Oxide Film;Oxidation Kinetics
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发布时间：2023-12-18
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