2011易切削铝合金的微观组织结构与性能

采用力学性能测试、DTA热分析、X射线衍射物相分析和透射电镜分析技术研究了时效工艺对固溶-冷拉处理的2011合金显微组织结构特征和力学性能的影响。结果表明：合金的最佳时效工艺为170℃／8h。在此条件下,合金棒材的抗拉强度为472MPa,屈服强度为378MPa,延伸率为10．1％;合金的物相组成为铝基同溶体、低熔点相Pb2Bi3和Bi以及主要强化相CuAl2。球形低熔点共晶组成物（Pb7Bi3＋Bi）的熔化温度为156．02％,CuAl2相的析出强化以及低熔点共晶组成物（Pb7Bi3和Bi）的存在使合金同时具有较高的强度和良好的易切削加工性能。     

钇对2519铝合金的组织与性能的影响

用X射线、光学显微镜及扫描电镜等研究了钇对2519铝合金的组织及力学性能的影响,实验结果表明:加入适量钇(0.1%质量分数)后,合金的强度、硬度、伸长率提高,合金的再结晶组织细化,当钇含量超过0.1%时,合金的强度、硬度、伸长率随钇含量的增加而逐渐降低,适宜的含钇量为0.1%,钇主要以Al6Cu6Y化合物的形式存在并沿晶界分布。     

回归再时效7150铝合金力学性能、剥蚀行为及微观组织研究

采用拉伸试验、剥蚀试验、硬度测试及透射电镜（TEM）观察研究了195℃回归时7150铝合金硬度变化及微观组织形祝,以及回归不同时间的RRA工艺对7150铝合金力学性能和剥蚀行为的影响,并与T6及T73进行了比较研究。结果表明,7150-T6铝合金强度高而剥蚀敏感性大;7150-T73铝合金强度降低而耐腐蚀性大幅度提高。195℃回归时,回归时间小于0．5h,7150-RRA铝合金强度高于7150-T6强度,而剥蚀敏感性未有效降低;当回归时间延长至1h,7150-RRA铝合金可保持7150-T6的高强度,而其剥蚀敏感性则大幅度降低。     

2A70合金棒材组织与性能稳定性研究

通过对高纯2A70合金棒材挤压及热处理的研究试验,确定影响其性能与组织的因素。制定最佳的挤压工艺及热处理制度,使棒材组织与性能稳定,满足用户的需要。     

Mechanical Properties and Microstructure of Thin Plates of A6061 Wrought Aluminum Alloy Using Rheology Forging Process with Electromagnetic Stirring

We propose the possibility of fabricating A6061 thin plates using the rheology forging process. Electromagnetic stirring (EMS) is used to fabricate a semi-solid slurry. A thin plate is formed by injecting the slurry into the forging die. When the punch speed used to compress the slurry is low, turbulent flow occurs. When the punch speed is high, laminar flow occurs, and the solid and liquid phases move simultaneously. For a pressure of 150 MPa or below, incomplete filling behavior and cracks occur. For a pressure of 200 MPa or above, a durable formed product can be obtained. However, the differences between the mechanical properties according to the application of EMS and pressure are slight. The microstructure of the slurry without EMS has an unclear distinction between the liquid phase and solid phase. However, the microstructure of the thin plates formed by using this slurry has a clear distinction between the liquid and solid with respect to the spheroid shapes. The tensile strength and elongation for a thin plate formed with a punch speed of 300 mm/s and pressure of 250 MPa with EMS slurry are 169 MPa and 11.0 pct, respectively. After T6 heat treatment, the tensile strength improves to 305 MPa.     

分级均匀化处理对7068新型高强铝合金组织及性能的影响

采用光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)及差热分析(DSC)研究了7068高强高韧铝合金均匀化热处理制度及其微观组织演变;通过单向拉伸试验及四探针电阻率法测定了不同均匀化后T6态合金的拉伸性能及电导率。结果表明:7068铝合金铸态组织存在枝晶偏析,非平衡共晶相沿晶界呈连续网状分布,低熔点共晶相初始溶解温度为467.3°C;合金经455°C×16h+465°C×4h+475°C×4h三级均匀化处理后,成分均匀,残留共晶很少且T6态的抗拉强度、延伸率以及电导率均达到所做均匀化处理中最佳,分别为715MPa、13.3%和34.5%IACS。     

The Microstructure,Texture and Mechanical Properties of Friction Stir Welded Aluminum Alloy

Russian Journal of Non-Ferrous Metals - The microstructure and texture of 7075-T6 FSW weld with optimal parameters are investigated using optical microscopy, electron back scatter diffraction and...     

W-Ni-Fe高密度合金的力学性能与显微组织研究

研究了W—Ni—Fe系高密度合金的力学性能与显微组织，并分析了相关的变化规律，从而探索了制取高性能W—Ni—Fe高密度合金材料的有效途径。     

纳米晶Al-Cu-Mg合金的微观组织与力学性能研究

以工程实际中应用较广的Al-Cu-Mg铝合金作为研究对象, 用Al-Cu-Mg铝合金气体雾化粉末作为原材料, 通过低温液氮球磨获得纳米晶后, 再经真空热压和热挤压制备了致密的大块体纳米材料. 通过力学性能测试, 挤压态的纳米晶Al-Cu-Mg块体材料抗拉强度达470 MPa, 经过T4处理后, 抗拉强度达到590 MPa, 远远超过常规方法制备的Al-Cu-Mg铝合金抗拉强度. 对纳米晶Al-Cu-Mg块体材料进行微观组织观察, 分析了材料强度提高的原因.     

Improving Microstructure and Mechanical Properties for Large-Diameter 7075 Aluminum Alloy Ingots by a Forced Convection Stirring Casting Process

Metallurgical and Materials Transactions B - A simple process so-called forced convection stirring casting (FCSC) was proposed to prepare large-diameter 7075 Al alloy ingots. The flow behavior,...     

铝合金点焊过程中铜铝合金化的有限元分析

为了研究铜铝合金化反应的机理,本文建立了一种基于铜和铝扩散反应进行的有限元模型。由于热传导方程和扩散方程在表达形式上的相似性,所以用模拟热传导的方式来模拟铝在铜电极中的单向扩散过程,以温度分布表示扩散浓度的分布情况。研究表明：若只考虑铝在铜中的单向扩散,将试验中的数据按比例进行换算,这样计算出来的试验结果与模拟结果比较相近。     

固溶处理对2E12铝合金显微组织和力学性能的影响

通过光学显微镜、扫描电镜、DSC差热分析、室温拉伸、硬度与电导率测试措施,研究了固溶处理对2E12铝合金轧制态板材显微组织和力学性能的影响。结果表明,随着固溶处理温度升高,固溶时间延长,合金基体内未溶残留相逐渐减少,材料屈服强度、抗拉强度逐渐升高,硬度在500℃/30m in和500℃/1h时出现峰值,伸长率呈上升趋势,电导率呈下降趋势;2E12铝合金较为适宜的固溶处理制度为495~500℃/1h。     

喷射成形超高强度Al-Zn-Mg-Cu合金的固溶处理

研究了单级固溶和双级固溶热处理工艺对喷射成形Al-Zn-Mg-Cu铝合金力学性能的影响.应用光学显微镜、扫描电镜与透射电镜对显微组织和第二相颗粒的固溶及沉淀析出状况做了进一步的研究.结果表明:双级固溶时效和单级固溶时效处理制度相比,前者得到的组织和力学性能较为理想;双级固溶处理综合了低温单级固溶和高温单级固溶的优点,即再结晶晶粒尺寸较小,同时回溶颗粒较多.时效后的组织也较理想.采用双级固溶处理(450℃/3h+480℃/3h)和T6时效处理后,合金的抗拉强度和屈服强度分别达到806MPa和797MPa,延伸率达到7.5%.     

5083 H321铝合金板材制备组织性能研究

基于"1+4"热连轧生产线、2800mm冷轧生产线,采用不同工艺线路制备了5083 H321铝合金板材,研究了不同制备工艺对板材组织性能的影响.结果表明,不同工艺路线成品板材力学性能、耐腐蚀性能及微观组织均存在明显差异.采用"1+4"热连轧生产线短流程工艺制备的5083 H321铝合金板材性能:抗拉强度358MPa、屈...     

Microstructure and Mechanical Properties of Cryorolled Aluminum Alloy AA2219 in Different Thermomechanical Processing Conditions

Metallurgical and Materials Transactions A - In the present study, aluminum alloy AA2219-T87 bars were cryorolled to various amounts of deformation in two pre-deformation conditions: (1) without...     

低密度NbTiAlCrSi合金显微组织及力学性能

采用真空自耗电弧熔炼法制备了密度为6.0 g/cm3的NbTiAlCrSi合金,并通过光学显微镜、扫描电镜、能谱仪等对其进行了组织观察和分析.结果表明:合金组织由(Nb,Ti)5Si3和(Nb,X)SS两相组成(X代表Ti、Al、Cr等元素),(Nb,Ti)5Si3呈条、块状网络连续分布的特点.对合金铸锭进行1 400℃/9 h均匀化退火处理不能显著改变(Nb,Ti)5Si3条、块的大小,但使得(Nb,Ti)5Si3第二相分布由连续的条、块转变为不连续的(Nb,Ti)5Si3块.该合金热轧态的抗拉强度达704 MPa,室温拉伸脆断.M5Si3型化合物特性以及热轧态中第二相与基体界面处所存在的细微孔隙导致了合金的脆性.     

Simulation of Semi-Solid Material Mechanical Behavior Using a Combined Discrete/Finite Element Method

As a necessary step toward the quantitative prediction of hot tearing defects, a three-dimensional stress–strain simulation based on a combined finite element (FE)/discrete element method (DEM) has been developed that is capable of predicting the mechanical behavior of semisolid metallic alloys during solidification. The solidification model used for generating the initial solid–liquid structure is based on a Voronoi tessellation of randomly distributed nucleation centers and a solute diffusion model for each element of this tessellation. At a given fraction of solid, the deformation is then simulated with the solid grains being modeled using an elastoviscoplastic constitutive law, whereas the remaining liquid layers at grain boundaries are approximated by flexible connectors, each consisting of a spring element and a damper element acting in parallel. The model predictions have been validated against Al-Cu alloy experimental data from the literature. The results show that a combined FE/DEM approach is able to express the overall mechanical behavior of semisolid alloys at the macroscale based on the morphology of the grain structure. For the first time, the localization of strain in the intergranular regions is taken into account. Thus, this approach constitutes an indispensible step towards the development of a comprehensive model of hot tearing.