最新刊期
卷 38 ， 期 8 ， 2018
- 摘要：In order to improve the mechanical properties of 2024（Al-Cu-Mg series）alloy,machinery multi-grinding of the surface（MMGS）processing was applied to form two pass deformation.The microhardness,mechanical properties and microstructure changes in commercial 2024 aluminum alloy after MMGS were investigated by micro-hardness test,mechanical properties test,transmission electron microscopy（TEM）and scanning electron microscopy（SEM）.The results reveal that,compared with the T351 state,micro-hardness and yield strength as well as tensile strength of the surface reach about 185 HV,475 MPa and about 498 MPa,increased by 18%,22% and 16%,respectively.Grains size of the surface is refined to about 800 nm.MMGS processing is one of the effective methods for the 2024 aluminum alloy to obtain the micro-nano crystallization.关键词：2024 Alloys;MMGS;Surface Micro-Nano Crystallization;Plastic Deformation
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发布时间：2023-12-18 - 摘要：Cavitation erosion test of copper-bearing antibacterial duplex stainless steel in artificial seawater was carried out by using a magnetostrictive cavitation test machine,and the cumulative loss weight and weight loss curve were measured by weight loss.The cavitation erosion mechanism was analyzed by OM,ESEM,EDS,XRD and so on.The results reveal that the cavitation erosion of the copper-bearing antibacterial duplex stainless steel after aging treatment at 560 ℃is divided into initial period,accelerated period,decreased period and stable period.Compare with the base material,the cavitation damage of copper-bearing antibacterial duplex stainless presents more serious.After 50 h,the weight loss of corrosion resistance of antibacterial materials and solution material reach 2.5 mg and 4.2 mg,respectively,and the cavitation damage of copper-bearing antibacterial duplex stainless steel after antibacterial aging is reduced.The fine and dispersion Cu-rich phase in antibacterial material can enhance the cavitation erosion resistance of ferrite,however the crystal structure of austenite and the sliding hindrance caused by internal dislocation determine that the cavitation erosion resistance is the higher than the ferrite with Curich phase.The micro-hardness of the antibacterial material and solution material is increased with the increase of cavitation time,however,the hardness value of antibacterial material is always higher than that of solid solution ones due to the dispersion of aging precipitation and rich Cu phase.关键词：Copper-bearing Antibacterial Duplex Stainless Steel;Aging Treatment;Cavitation Erosion;Microhardness;Cu-Rich Phase
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发布时间：2023-12-18 - 摘要：In view of the uneven variation of tensile strength of ZL305 Aaluminum alloy in natural aging treatment,the change trend of tensile strength of ZL305 Aalloy was predicted by combining wavelet transform with grey DGM（2,1）model.The noise in the original time series was removed by the wavelet transform,and then the DGM（2,1）model was established with the new time series generated to predict the original time.The results reveal that the average prediction error is only 0.466 5%,which is decreased by 1.228% and the finished time is-0.260 76%,which is decreased by 65.066 2%.关键词：Wavelet Transform;GM（2,1）;ZL305A;Aging Treatment;Mechanical Properties
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发布时间：2023-12-18 - 摘要：<正>2018年7月13日,港股公司中州证券（即中原证券香港上市的简称,股票代码:01375）发布公告,中州蓝海、河南煤炭及其他出资人订立出资协议,拟成立鹤壁镁交易中心,注册资本为1亿元,经营范围为镁锭、镁棒及相关产品和成品现货交易平台的服务与管理,镁锭、镁棒等镁原料和成品
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发布时间：2023-12-18 - 摘要：<正>近日,空军军医大学西京医院骨科郭征教授团队成功将具有渐变仿人体骨骼结构的钛合金支撑棒植入一股骨头坏死的患者体内,有效改善患者关节功能。据悉,采用渐变仿人体骨骼结构支撑棒临床治疗股骨头坏死尚属全球首次,为股骨头坏死治疗提供了新方案。来自榆林市的42岁患者李某,6个月前出现左髋关节疼痛,下蹲或劳累时痛感明显加重,但一直没有进行针对性治疗,导致
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发布时间：2023-12-18 - 摘要：<正>广东鸿特科技股份有限公司（"鸿特科技"）发布公告,公司全资子公司广东鸿特精密技术（台山）有限公司（"台山鸿特"）拟与重庆市明鑫机械制造有限公司（"明鑫机械"）合资设立重庆鸿特精密技术有限公司（暂定）。据了解,双方设立的合资公司,注册资本3 000万元,主要从事铝合金精密压铸件、汽车零部、汽车双离合器变速器
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发布时间：2023-12-18 - 摘要：<正>2016年,伊之密重磅推出HPM技术的中国版本——H系列重型压铸机,并在2017年陆续推出高标准的超重型压铸机（35000～45 000kN）和HPM4500T压铸机,大举迈入重型时代,用更接近欧洲质量标准的高性能压铸机服务于全球市场。下面,盘点伊之密重型压铸机的成绩单。有着62年重型汽车生产经验的中国重汽,去年买入一
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发布时间：2023-12-18 - 摘要：<正>近日,中国科学院合肥物质科学研究院固体物理研究所极端环境量子物质中心在合成超高含能材料金属氮方面取得突破。量子中心科研团队采用超快探测方法与极端高温高压技术,以普通氮气为原材料,成功合成了超高含能材料聚合氮和金属氮,揭示了金属氮合成的极端条件范围、转变机制和光电特征等关键问题,将金属氮的研究向前推进了一大步。含能材料广义上指蕴含有大量可释放化学能的一类物质,主要类别包括发射药、推进剂、炸药、烟火剂等。绿色高含能材料
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发布时间：2023-12-18 - 摘要：<正>2018年7月19日,2018中国（四川）先进材料产业推进会·钒钛稀土产业链推进会在成都举行。会上,陕西宝鸡力兴钛业集团与攀枝花钒钛高新区管委会签订框架协议,将投资15亿元,分两期建设年产2万吨海绵钛及1万吨钛材。此次推进会结合四川战略资源丰富的优势,瞄准先进材料产业前沿,抓住国内外龙头企业,突出知名院士专家引
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发布时间：2023-12-18 - 摘要：<正>室温下又硬又脆,加热后又软又弹,而且"刚"与"柔"可以随着温度的变化来回循环。南京大学化学化工学院李承辉副教授团队研发出一种"刚柔并济"的高分子新材料,该研究成果日前发表在《自然·通讯》杂志上。"这种材料的最大突破点在于解决了机械强度与自修复性能之间的平衡难题。"李承辉介绍,新材料在从室温到60℃的温度变化过
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发布时间：2023-12-18 - 摘要：<正>由中国铸造专家提交的一份国际标准提案及其草案,近日通过了国际标准化组织"铸造机械技术委员会（ISO/TC 306）"的新工作项目（NP）投票,并正式在ISO获批立项,制定周期为36个月。这意味着首次由中国主导制定的铸造行业国际标准提案,将在完成ISO规定的后续各阶段
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发布时间：2023-12-18 -
Influences of Gd Content on the Microstructure and Mechanical Properties of Sand-cast Mg-Gd-Y Alloys
摘要：Influences of Gd content（012.7%）on the microstructure and mechanical properties of sandcast Mg-Gd-Y alloys were investigated by OM（optical microscopy）,SEM（scanning electron microscopy）and tensile test.Relationships between Gd content and the average grain size ofα-Mg,yield strength and ultimate tensile strength were established.The morphology of the fracture was observed,and the crack behavior was described.The average grain size ofα-Mg is decreased from 112μm to 54μm,and yield strength,tensile strength of the alloy are increased from 64.9 MPa to 174.3 MPa and from 157.5 MPa to 221.2 MPa,while elongation is decreased from 21.3%to 0.9% with Gd content increased from 0 to 12.7%in the alloy.The alloy with 10.2% Gd content possesses the desirable mechanical properties,where yield strength,tensile strength and elongation reach 140.0 MPa,196.1 MPa,3.3%,respectively.关键词：Mg-Gd-Y Alloys;Sand-cast;Microstructure;Mechanical Properties- 2
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发布时间：2023-12-18 - 摘要：In the field of ultrasonic testing on in-cast bimetal turbine combined layer,due to the combining layer approximately perpendicular to the floor,and the low reflection waveform energy caused by internal high attenuation in turbine materials,bistatic phased array detection model becomes the desirable choice.For this kind of bistatic model adopted by bimetal combined layer defection,firstly,depthdelay fast table was established according to a two-dimensional acoustic line model based on the actual turbine structure,and then a method was put forward based on the OCOG algorithm after the adjustment of receiving data delay interception,which can orientate the defections precisely.The difference between direct wave equivalent frontier and gravity of defect wave was used to solve the corresponding defect depth fitting function in advance.Finally,all waveform data of the same depth was displayed according to the amplitude imaging.The experiment shows that the detection method by OCOG algorithm has high detection rate and accurate location of the defect.关键词：Bimetal Turbine;Ultrasonic Phased Array;Bistatic;Defect Localization
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发布时间：2023-12-18 - 摘要：The influences of the pressure,temperature and duration time of Hot Isostatic Pressing（HIP）on the ultimate tensile strength（UTS）of Ti2 AlNb casting samples were investigated.It is found that the influence of HIP pressure on the UTS of the Ti2 AlNb casting samples can be ignored while the plasticity can be improved greatly with the increase of HIP pressure.The microstructure with fine Ophases dispersed in B2 matrix can be obtained by the HIP treatment of Ti2 AlNb alloy at a temperature from1 040 ℃to 1 100℃for 3 h,and the samples exhibit high tensile strength.The UTS of Ti2 AlNb casting can be improved greatly by HIP at 1 040 ℃for 1.5 to 3 h,while the UTS of the samples is decreased when the duration of HIP is increased to 4 h.关键词：Ti2AlNb Alloy;HIP;Castings;Tensile Strength
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发布时间：2023-12-18 - 摘要：Iron is considered to be a very harmful impurity in aluminum alloys,which always accumulates in recycling aluminum alloys,so it is critical to control the detriment of the iron-rich intermetallics in order to promote scrap aluminum recycling and efficient use.The iron-rich intermetallics in Al-Cu cast alloys was reviewed,including the morphology and control methods of iron-rich intermetallics.The results reveal that the morphology and type of iron-rich intermetallic compounds in Al-Cu alloys are dependant of different alloy compositions and casting conditions,including needle-likeβ-Fe,Al3（FeMn）and Chinese scriptα-Fe,AlmFe,Al6（FeMn）.The needle-likeβ-Fe is considered to be the most stable iron-rich intermetallic compounds in the heat treatment process,and other iron-rich intermetallic compounds will be transformed intoβ-Fe during the heat treatment.Modification of the morphology of ironrich intermetallic compounds is an effective way to control iron-rich intermetallic compounds in cast AlCu alloys,including neutralization,changing the casting process and applying physical fields.However,it can’t solve these problems fundamentally because the increase of iron-rich intermetallic compounds leads to the reduction of precipitates particle in the Al matrix.The future direction is to develop more effective neutralization or efficient and economic iron removal technologies.The research of iron-rich intermetallic compounds in cast Al-Cu alloys was mainly focused on gravity die casting condition,and the research of iron-rich intermetallic compounds under special conditions such as ultrasonic and pressure fields should be paid attention.关键词：Al-Cu Cast Alloys;Iron-rich Intermetallics;Control Methods
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发布时间：2023-12-18 - 摘要：ZK60 magnesium alloy ingots with the diameter of 500 mm were fabricated by the semi-continuous casting.The melt was well purified by low pressure transferring the melt and standing technique.The effects of the casting parameters on the metallurgy quality of the ingots were investigated and the reasonable parameter windows were established.The metallurgy defects were analyzed to understand the formation mechanism of the defect.The characteristics of the microstructure was also observed.The results reveal that the casting velocity has the significant effect on the metallurgy quality of the ingot.The through-crack can be formed in the center zone of the ingot in case of using the higher velocity or the higher water flow.The microstructure of the large-scale ZK60 magnesium alloy is composed of equiaxed grain withα-Mg matrix and the second phases MgZn2 which are precipitated in the grain and the grain boundary discontinuously.The grain in the edge of the ingots is much more refined than that of the center of the ingots.关键词：Large Scale Ingot;ZK60 Magnesium Alloy;Semi-continuous Casting;Microstructure
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发布时间：2023-12-18 - 摘要：By using the independent optimization function of the MagmaSOFT,through the verification design of process parameters and riser geometry,virtual experiment can run in the software,and process development and defect optimization can be carried out.With the software evaluation tool,it can be more effective to forecast the influence trend of each process parameter to the defect.The optimized technological scheme calculated by virtual experiment has been proved to be effective in reducing the porosity and oxide.关键词：Casting Defect;Magma Simulation;Piston
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发布时间：2023-12-18 - 摘要：The drawing process of pure magnesium thin wire was numerically simulated by controlling the different friction coefficients,drawing speeds and the amount of pass deformations based on the constitutive equations established by the thermal compression.The results reveal that drawing force and strain non-uniformity as well as maximum main stress are increased with the increase of the friction coefficient.With the increase of drawing speed,the change of drawing force can be ignored,while the strain non-uniformity and the maximum main stress are increased gradually.The maximum main stress is increased dramatically when the drawing speed is more than 60 mm/s.With the increase of pass deformation,the fracture tendency value is increased and it is increased sharply at pass deformation exceeding 15%.Therefore,the optimized drawing parameters of pure magnesium thin wire are presented as follows:the friction coefficient of 0.08,the drawing speed less than 60 mm/s and the pass deformation in range of10%15%.关键词：Pure Magnesium Wire;Finite Element Simulation;Friction Coefficient;Drawing Speed;Pass Deformation
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发布时间：2023-12-18 - 摘要：Aluminum alloy housing is an important component in AC fan,so die-casting die is one of the most important equipment in the production of fan.For die casting die for double-flange housing,aiming at the requirements of three corresponding parting surfaces and the interference situation during longdistance core-pulling,based on practice and structural optimization analysis,pre-reset mechanism was achieved,which has a fixed-moving die parting surface with concise structure,convenient machining,artistic parting surface and absence of casting fin as well as an optimal design of zero-failure.High-efficiency low-cost spiral groove sprue bush was adopted to solve the distortion problem of the flow gate of center gate.关键词：Gating System;Parting Surface;Spiral Groove Sprue Bush;Center Gate;Ingate
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发布时间：2023-12-18 - 摘要：The casting scheme of ZL114 Aalloy cylindrical shell castings was designed according to the properties of alloy and the structural characteristic.The optimized process scheme and parameters of cabin shell was provided with local chilling and a higher pressure difference by related numerical simulation and process test analysis.The window position of the ZL114 Ahousing under low pressure casting was analyzed.The results reveal that after solid solution and dual-aging treatment,tensile strength,yield strength and elongation reach 349 MPa,288 MPa and 7.7%,respectively,meeting the design requirements.关键词：ZL114A alloy;Cabin Shell;Low Pressure Casting;Numerical Simulation;Mchanical Properties
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发布时间：2023-12-18 - 摘要：Based on the requirement of lightening for an electric vehicle structural part of the shock tower,influence of the aluminum design on weight-reduce was analyzed and a high vacuum die-casting process suitable for the aluminum alloy shock tower was developed.The results reveal that the rational mould design can decrease the weight of the shock tower by about 35% based on assemble,rigidity and die casting process.In addition,the reasonable design of the casting system and the control of the vacuum degree are the important factors affecting the stability of the air-gap and mechanical properties.Based on the analysis of bubble test and mechanical analysis,the design of ingate was optimized.The shock tower part can be achieved with tensile strength higher than 300 MPa yield strength higher than250 MPa and the elongation higher than 8%,after T6 heat treatment,meeting the requirement of OEM.关键词：Structural Part;Shock Tower;High Vacuum Die Casting;Heat Treatment
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发布时间：2023-12-18 - 摘要：With the help of indirect squeezing casting and horizontal TRD-800 Tsqueezing casting machine,effects of squeezing casting parameters on microstructure and properties of automobile control arm were investigated.The results reveal that at a certain range,with the increase of specific pressure,the mechanical properties of the control arm are improved,however,with specific pressure more than140 MPa,improvement of the properties can be ignored.The lower specific pressure is beneficial for improving the macro-defects in the control arm.While the higher specific pressure can increase the solidified velocity of the aluminum alloy melt to refine greatly microstructure.At specific pressure of 140 MPa,the average tensile strength and elongation,hardness of the control arm reach 354 MPa,11%and112（HB）,respectively.Meanwhile,internal quality of the squeezing control arm presents desirable with absence of shrinkage porosity（hole）,crack,inclusions.关键词：Control Arm;Indirect Squeezing Casting;Microstructure;Mechanical Properteis
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发布时间：2023-12-18 - 摘要：It’s necessary to ensure the stability of a horizontal continuous casting five-strand tundish for casting aluminum.To obtain uniform temperature distribution and fluid flow,the flow-control device of a tundish for a five-strand horizontal continuous caster was designed and optimized using three-dimensional mathematical modeling and water simulation experiments.The results reveal that the velocity of aluminum melt exhibits uniform at outlet,and it is near to the casting speed as a whole by utilizing the flow control device.The maximum temperature difference in the whole original tundish is 15 K,while it is 9 Kin the optimized tundish with flow control device,decreased by 40%.The maximum temperature difference of each outlet in the original tundish is 7 K,while it is 2 Kin optimized tundish,decreased by71.4%.The flow control device of a five-strand tundish designed is beneficial to improving the quality of ingots and stabilizing manufacturing process.关键词：Tundish;Flow-control Device;Fluid Field;Temperature Field;Numerical Simulation
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发布时间：2023-12-18 - 摘要：The semi-solid slurry of 7075 aluminum alloy was prepared via series water-cooled copper serpentine pouring channel machine which was self-designed and built.Influences of pouring temperature,the curve numbers and the cooling water on the microstructure of semi-solid 7075 alloy slurry were investigated.The results show that the semi-solid 7075 aluminum alloy slurry with satisfied quality can be prepared by a serpentine pouring channel when the pouring temperature is in range of 680700 ℃.The average grain size of primaryα-Al in the semi-solid slurry is less than 41μm and the shape factor is more than 0.79.With a given pouring temperature,the equivalent size of the primaryα-Al grains is decreased and the shape factor is increased with the increase of the curve numbers.When the cooling water is 450 L/h,the obtained semi-solid slurry has the satisfied microstructure.During the slurry preparation of semi-solid 7075 aluminum alloy with low superheat pouring,the alloy melt changes flow direction many times when it flows in a curved and closed serpentine channel with the effect of"stirring"in the serpentine curve,so the primary nuclei is gradually evolved into spherical and near-spherical grains.关键词：7075 Al Alloy;Semi-solid Slurry;Water-cooled Copper Serpentine Channel;Primary α-Al
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发布时间：2023-12-18 - 摘要：The View-cast software was used to simulate lost foam casting process of the vermicular cast iron mold,and scheme was optimized according to the simulation results.The simulated result and production reveal that the defects can be reduced when the two molds are placed at the angle of 120°135°,meanwhile,the mold’s upper lip is tilted up,and the lower lip is tilted down and the inner runner is located below the middle of the ear standing on the casting mold.And the castings meeting the requirement were finally obtained.Not only is the heat conduction function increased and thermal stress decreased,but also the generation and growth of the crack and the moving of dislocation are controlled as the result of a number of vermicular graphite uniformly distributed in the structure,so the serving life is enhanced effectively.关键词：Cast Iron Mold;Lost Foam Casting;Simulation;Microstructure and Properties
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发布时间：2023-12-18 - 摘要：Thermal fatigue behavior of K4169 Ni-based superalloy for thin-walled investment castings in the process of aero-engines service was analyzed by the fluorescent microscopic examination method,optical microscopy（OM）and scanning electron microscope（SEM）,and the fatigue crack initiation and propagation mechanism were also described.The results indicate that almost all the primary fatigue cracks are initiated from the carbides at the notch sensitivity of specimen formed during the machining process,Subsequently,only one or two small thermal fatigue cracks can continue to grow and propagate along apreferential direction with the dendrite growth direction or along the intergranular region which carbides can be easy cracked due to different thermal expanding coefficients of the matrix and the carbides,and the crack of MC carbides either at grain boundaries or within the grain interior as well as the high-temperature oxidation are played an important role on crack propagation.The rapid fatigue fracture morphology exhibits quasi-cleavage and dimples feature.关键词：K4169 Superalloy;Thin-Wall;Thermal Fatigue Initiation;Fatigue Crack Propagation
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发布时间：2023-12-18 - 摘要：The effective control measures were adopted to improve the casting quality and to reduce or eliminate the slag inclusion defects through design of the process structure to the production process,thus improving the sealing performance of the valve and flange castings.The practical production verifies that:（1）the wax tree-assembling design of the process structure should avoid the sealing surface of the castings to be set in the slag surface of the process structure,or to set the scum riser on the casting scum surface,or to increase the processing allowance on the casting scum surface,which could reduce or avoid the slag inclusion to a certain extent.（2）during the production process,the wax impurity during wax reclamation should be reduced to avoid the inclusion falling into the shell mould cavity after dewaxing.At the same time,some measures should be paid attention,such as the selection of raw materials before casting,the deoxidization practice in the process of melting,the secondary oxidation of the molten steel and seting rational pouring temperature,to avoid or reduce effectively the defects in the castings.关键词：Slag Inclusion;Assembly Tree;Deoxidization
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发布时间：2023-12-18 - 摘要：Through adopting the annular runner and introducing the ingate in radial direction,setting the overflow feeding riser in both sides of the flange,gating system was designed.The size of sprue、runner and feeding riser were determined by the shrinkage modulus method,and the pouring cup adopted a light anti-splash standard style recommend by DISA molding line.With the gating system and riser feeding technology,the tee products were produced in the vertical molding line.The practical production shows that the intrinsic quality of castings exhibits desirable with absence of shrinkage porosities（holes）,and the casting qualified rate reaches 96%,and the yield production rate is 68%.关键词：Tee;Gating System;Proportional Solidification;Riser
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发布时间：2023-12-18 - 摘要：Selective laser sintering（SLS）technology has been widely used in precision casting due to its ability to form complex investment patterns especially in the formation of complex parts of aerospace.The forming of investment pattern is an important part of investment casting,and the forming dimensional accuracy is especially important.In order to understand effect of the structure on the forming dimensional accuracy of SLS,the thin wall,circular hole and flange structure were analyzed in the investment castings.Firstly,polystyrene samples were prepared by SLS technology,and three-dimensional scanning techniques were used to obtain the deformation results of three sets of samples.Secondly,the scanning results were compared with the original geometric model,and the size deviation comparison and cylindricity comparison mean were used to analyze influence of structure on dimensional accuracy.It is concluded that the circular hole structure can change the radial contraction and reduce the dimensional accuracy.The flange structure can restrict the deformation of sintered parts and improve the dimension accuracy.关键词：Selective Laser Sintering（SLS）;Polystyrene（PS）;Feature Structure;Dimensional Accuracy
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发布时间：2023-12-18 - 摘要：The ZrMgMo3O12/2024 Al composites with 10% ZrMgMo3O12 in volume fraction were prepared through mixing 2024 Al powder and ZrMgMo3O12 powder with various milling time and milling speed.The microstructure,hardness and coefficient of thermal expansion（CTE）of composites were investigated using SEM,XRD,Vickers hardness tester and dilatometer,respectively.The results reveal that with increasing in milling rate and milling time,the ZrMgMo3O12 particles are distributed uniformly inα-Al matrix with excellent bonding,which are beneficial to the dispersion strengthening effect of ZrMgMo3O12 particles to Al matrix and improvement of the mechanical properties as well as improvement of the interfacial load transfer capacity on the interface of ZrMgMo3O12/Al matrix.Finally,the superposed effect of the coefficient of thermal expansion of ZrMgMo3O12 and 2024 Al is increased and the thermal expansion of composites is decreased.Therefore,the 10% ZrMgMo3O12/2024 Al composites fabricated with milling rate of 200 r/min for 4 hhas not only higher than that of 2024 Al in hardness,but also the lowest CET（16×10-6 K-1）.关键词：Negative Expansion Ceramics ZrMgMo3O12;2024Al Composites;Ball Milling Process;Hardness
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发布时间：2023-12-18 - 摘要：The laminated composite sheet of LZ91 and AA1050 was prepared by accumulative roll bonding（ARB）.The effects of stacking rolling cycles on mechanical properties and microstructure of the composite sheet were investigated by tensile machine,optical microscope,scanning electron microscope and X ray diffraction.The results show that thickness of the composites sheet after 3 cycles rolling are very close.The average particle size of theαphase in the LZ91 layer parallel to the rolling force is decreased to 0.3μm from 2μm,and the grain refinement effect of subsequent rolling can be ignored.With the increase of the rolling cycles,the mechanical properties of the composite sheet are increased firstly and then reduced.The tensile strength,yield strength and microhardness of the composites sheet after 3 cycles rolling are increased by 42.11 MPa,71.93 MPa and HV16.5,respectively.New intermetallic compounds are absent in the LZ91/AA1050 lamellar composite sheets.关键词：Accumulative Roll Bonding;Laminated Composite Sheet;Mechanical Properties;Grain Refinement
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发布时间：2023-12-18 - 摘要：The microstructure and mechanical properties of AZ91 Dcomposites with different SiCpcontent were investigated by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）and tensile testing when the billet surface temperature was 350 ℃ and the differential temperature was150℃.The results show that SiCpparticle distribution is more uniform with more fine grain size with the increase of SiCpcontent,which is mainly attributed to generation of non-basal slip system and deformation twins making microstructure more uniform.The addition of SiCpcan be acted as grain recrystallization nuclei and promote the formation of recrystallization grain,and some SiCpparticles at the grain boundary can inhibit boundary movement and refine the grain size.With 0.5% SiCp/AZ91 Dcomposite exhibits ultimate tensile strength of 315 MPa,ultimate yield strength of 209 MPa,elongation of 10.3%.关键词：Differential Temperature Extrusion;SiC Particles;AZ91D Alloy;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Due to many types of elements,high content and large differences in elemental density of AlZn-Mg-Cu alloy the segregation and crack in the solidification process are easily formed,so it is difficult to be conventional cast directly.Effects of Annular Electromagnetic Stirring（A-EMS）melt treatment for Al-11.8 Zn-2.9 Mg-1.1 Cu alloy under different castings conditions was carried out.The results reveal that,under A-EMS,grain refinement and homogeneity can be improved greatly,meanwhile,hot-cracking tendency in the casting process is significantly decreased.关键词：Annular Electromagnetic Stirring;Melt Treatment;Microstructure
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发布时间：2023-12-18 - 摘要：The hot compression deformation behavior of AE42 magnesium alloy and it’s microstructure were investigated by using SanSi universal testing machine（UTM5105 G）at 573723 Kand the strain rate of 0.000 10.1 s-1.The results reveal that the flow stress is decreased with the increase of deformation temperature and the decrease of strain rate.With increasing in the temperature and decreasing in the strain rate,the microstructure of the AE42 alloy is transformed from twin grain to dynamic recrystallization（DRX）.关键词：AE42 Magnesium Alloy;Hot Compression Deformation Behavior;Flow Stress;Microstructure;Constitutive Equation
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发布时间：2023-12-18 - 摘要：The hypereutectic Mg-3.2 Si alloy was modified by Mn.Effects of Mn addition on the modification of primary Mg2 Si and mechanical properties of Mg-3.2 Si alloy were investigated.Experimental results show that the primary Mg2 Si can be modified effectively.With 2% Mn addition,the morphology of primary Mg2 Si is changed from equiaxed dendritic to polyhedral.The average particle size of primary Mg2 Si reaches 32μm,decreased by 56.8%,compared with those of the unmodified alloy.The tensile strength and elongation of the modified alloys are increased with Mn addition increase.With 2% Mn addition,the tensile strength and elongation of the Mg-3.2 Si alloy reach 167 MPa and 3.2%,increased by49.1% and by 166.7%,respectively,compared with those of the unmodified alloy.关键词：Mn;Mg-3.2Si Alloy;Primary Mg2Si;Modification;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The effects of deformation on the microstructure and the grain refinement performance of AlTi-C-B seed crystal alloys deformed by cold rolling were investigated.It is found that the coarse TiAl3 phases are broken and the TiCxBy particles in the matrix are more dispersive.The average grain size ofα-Al can be refined from 1 500μm to 240μm with adding 0.2%as-cast Al-5 Ti-0.3 C-0.2 Bseed crystal alloy.It is found that the grain size is further decreased to 165μm by adding the seed alloy with 60% deformation rate at the same addition and the good refinement performance can be stayed within 75 min without obvious fading.However,with the further increase of deformation to 90%,the grain refinement effect of the seed crystal alloy is decreased slightly,which is still better than that of the as-cast ones.关键词：Al-Ti-C-B Seed Crystal Alloy;Grain Refinement;Deformation;Microstructure
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发布时间：2023-12-18 - 摘要：The effects of homogenization treatment on microstructure and properties of 7 A55 aluminum were investigated.The microstructure was sobserevd using OM and SEM.The hardness and mechanical properties of the alloy were tested.The results indicate that the hardness,strength and elongation of7 A55 aluminum alloy are increased after different homogenization treatment compared to the cast state.After three-stage treatment,the hardness,tensile strength and elongation of the alloy are increased about 27%,12.3% and 58.3%,respectively.The cast structure is improved after homogenization treatment,including non-equilibrium eutectic phase at grain boundaries and bulky second phase in grain.The multi-stage homogenization effect is superior to single homogenization treatment,especially three-step treatment.The eutectic phase at grain boundaries become fine and discontinuous,and the bulky second particles in grains are dissolved into the grain.关键词：Al-Zn-Mg-Cu Aluminum Alloy;Homogenization Treatment;Microstructure Evolution;Mechanical Properties
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发布时间：2023-12-18 - 摘要：A series of Zn-xSr（x=0,0.5%,1%,2%,3%）binary alloy samples were prepared by smelting method.The microstructure,mechanical properties and corrosion resistance of the Zn-xSr binary alloy were investigated by metallographic,XRD,microhardness,electrochemical measurements and immersion test in Hank’s simulated body fluid.The results reveal that with the increase of strontium addition,the second phase（SrZn13）in the microstructure of zinc alloy is gradually increased with the increase of the size,resulting in the increase of the hardness gradually,while the corrosion resistance is deteriorated.The micro-hardness of Zn-xSr（x=0,0.5%,1%,2%,3%）alloy reaches 38,52,60,89,110 HV,respectively,and the corrosion rate in Hank’s simulated body fluid are 2.871,6.086,6.665,7.147,7.746 g·m-2·d-1,respectively.关键词：Zinc Alloy;Microstructure;Microhardness;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：As-cast Cu-38.72 Zn alloy was carried out cryogenic treatment,and effects of cryogenic treatment on corrosion resistance and thermal diffusivity coefficient of the alloy were investigated by means of optical microscope,profilometer,electrochemical testing and thermal constant tester.The results show that cryogenic treatment can reduce its corrosion resistance in 3.5% NaCl solution and thermal diffusivity coefficient.Compared with cast samples at room temperature,the average corrosion rates are increased by 3.75%,and the thermal diffusivity coefficient is decreased by 6.65%.关键词：Cu-38.72Zn Alloy;Cryogenic Treatment;Corrosion Resistance;Thermal Diffusivity Coefficient
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发布时间：2023-12-18
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