6061 Al/AZ31B Mg/6061 Al对称复合板的组织与力学性能（英文）

在理论分析与模拟计算的基础上,通过热轧制备了6061 Al/AZ31B Mg/6061 Al对称复合板,并对其组织结构和力学性能进行了研究。首先通过经典复合板理论计算得到了复合板中6061 Al的最佳包覆率,再通过有限元方法模拟得到了复合板的最佳压下率。依据理论分析和仿真计算得到了铝的最佳包覆率和复合板的最佳压下率,对6061 Al/AZ31B Mg/6061 Al复合板进行组坯,并在不同轧制温度、不同压下率和不同退火时间下进行了轧制实验,最后对实验得到的复合板进行了拉伸性能测试、微观组织和能谱分析。结果表明,在复合板的复合界面处的镁层中发现了再结晶晶粒,且界面上形成了由Mg_(17)Al_(12)和Mg_2Al_3组成的金属间化合物;随着轧制压下率的增大,6061 Al/AZ31B Mg/6061Al复合板的抗拉伸强度、延伸率和界面扩散厚度显著增大;随着轧制温度的升高,复合板的抗拉伸强度、延伸率和界面扩散厚度也增大;而随着退火时间的增加,复合板的抗拉伸强度降低,但界面扩散厚度增加。     

6061/AZ31B/6061对称复合板的组织与力学性能研究

本文在理论分析与模拟计算的基础上,通过热轧制备了6061 Al/AZ31B Mg/6061Al对称复合板,并对其组织结构和力学性能进行了研究。首先通过经典复合板理论计算得到了复合板中6061Al的最佳包覆率,再通过有限元方法模拟得到了复合板的最佳压下率。依据理论分析和仿真计算得到的铝的最佳包覆率和复合板的最佳压下率,对6061 Al/AZ31B Mg/6061Al复合板进行组坯,并在不同轧制温度、不同压下率和不同退火时间下进行了轧制实验,最后对实验得到的复合板进行了微观组织、拉伸性能和能谱分析。结果表明,在复合板的复合界面处的镁层中发现了再结晶晶粒,且界面上形成了由Mg17Al12和Mg2Al3组成的金属间化合物;随着轧制压下率的增大,6061 Al/AZ31B Mg/6061Al复合板的拉伸强度、延伸率和界面扩散厚度显著增大;随着轧制温度的升高,复合板的拉伸强度、延伸率和界面扩散厚度也增大;而随着退火时间的增加,复合板的拉伸强度降低,但界面扩散厚度增加。     

Mg/Al复合材料成型及其组织性能研究

选取Mg-8.5Al-0.5Zn-0.2Mn合金、ZAlSi12合金和中间隔板1060合金为原料,采用铸造成型的方法制备出了Mg/Al层状复合材料,研究了中间隔板厚度对复合材料组织和力学性能的影响。结果表明,复合材料中Mg-8.5Al-0.5Zn-0.2Mn合金、ZAlSi12合金和中间1060合金层结合紧密、在界面处无明显缝隙或者孔洞存在;在过渡层与Mg-8.5Al-0.5Zn-0.2Mn合金和ZAlSi12合金界面处都存在一定的硬度梯度,且中间过渡层硬度都要低于Mg-8.5Al-0.5Zn-0.2Mn合金和ZAlSi12合金母材;中间隔板厚度对Mg/Al复合材料的强度影响较小,而断后伸长率随着中间隔板厚度的增加而逐渐降低。     

压下率对冷轧铝/钢(4A60/08Al)复合带材组织性能的影响

结合金相组织观察、显微硬度测量及室温拉伸实验, 对压下率分别为30%、40%、50%及60%时的4A60/08Al冷轧复合带的组织与力学性能进行了研究。采用模拟钎焊后拉剪实验对复合带的界面结合强度进行了评价。结果表明: 随着压下率的增加, 复合带钢层的硬度和屈服强度明显增加, 而铝层的硬度变化不大; 压下率从30%增加到50%时, 界面平均抗剪强度从52 MPa增加到65 MPa, 拉剪断裂位置也从铝钢界面断裂过渡到铝层断裂, 因此把压下率50%定义为4A60/08Al冷轧复合带的稳定压下率; 另外, 当压下率超过50%时, 复合带材的钢层在520℃×24 h退火后的组织基本为等轴的再结晶组织, 综合力学性能良好。     

轧制及T6处理对SiCp/6061Al复合材料拉伸力学性能的影响

对铸态SiC_p/6061Al复合材料分别实施了热轧及热轧+T6处理两种后处理工艺，采用扫描电镜、X射线衍射仪及拉伸试验设备，研究了热轧及T6处理对复合材料显微组织及抗拉强度的影响。结果表明，热轧可以有效地细化铸态SiC_p/6061Al复合材料内的增强颗粒，并消除材料内部孔洞，从而提高材料的抗拉强度。试样在拉伸外力作用下，在增强颗粒与基材间的界面处首先出现裂纹，裂纹扩展后使试样整体断开，热轧后对试样进行T6处理可以有效地消除轧制引起的增强颗粒与铝基材界面处的残余应力，提高增强颗粒与基材间的浸润性，从而提高材料的抗拉强度。在拉伸外力作用下试样中的增强颗粒首先开裂，裂纹扩展后使试样整体断裂。SiC_p/6061Al复合材料随着轧制压缩率的增大，材料的抗拉强度先增大后减小，轧制压缩率为60%的热轧+T6处理的试样在室温和200℃下的抗拉强度均达到最大，分别为350和290 MPa。     

Al/LZ91/Al三层复合轧制板材组织及界面扩散行为

采用金相显微镜,扫描电镜,观察了Al/LZ91/Al复合板界面组织和形貌,研究了不同退火参数对复合板界面扩散和拉伸性能的影响,并建立了扩散方程。结果表明,Al/LZ91/Al三层复合板退火后中间层LZ91镁合金发生了回复和再结晶,先前轧制被拉长而变形了的晶粒退火后转变为均匀而细小的等轴晶粒。Al/LZ91/Al三层复合板退火后界面发生了Mg和Al等元素的扩散,界面由基体α-Mg+β-Li相、Mg17Al12相、Al3Mg2相以及α-Al相等组成;退火温度为300℃保温1h后的三层复合板抗拉强度和伸长率最大,分别达到130 MPa和15.8%。     

波纹辊辊形参数对轧制Cu/Al层合板翘曲的影响

采用传统方法轧制Cu/Al层合板的过程中易出现翘曲变形,新型波纹辊轧制对改善其翘曲变形具有积极作用,为探究波纹辊辊形参数对轧制Cu/Al层合板的翘曲的影响规律,借助数值模拟方法,研究了轧辊波纹幅值与周期对轧制Cu/Al层合板翘曲的影响。结果表明：对于给定初始厚度的Cu/Al层合板,其翘曲曲率随着波纹幅值的增大先减小后增大,随着波纹周期的增大而增大,其中,波纹幅值为0.2 mm、波纹周期为πmm的波纹辊轧制的Cu/Al层合板的翘曲曲率最小。研究结果可为制备高板形质量的Cu/Al层合板提供技术参考。     

轧制压下率对Cu/Al层状复合材料界面扩散层生长的影响

采用金相显微镜、SEM及EDS等分析手段对Cu/Al冷轧复合界面结合机理进行研究,建立扩散退火阶段不同轧制压下率时的扩散层生长动力学方程,并探讨了不同压下率对界面扩散层生长的影响。结果表明,轧制复合阶段界面形成激活中心数量随压下率的升高而增加,当压下率为75%时达到峰值。另外,压下率在退火温度较高时对扩散层生长影响显著。     

高周期累积叠轧法制备Mg/Al多层复合材料

采用累积叠轧法(ARB)对Mg/Al多层板材进行高周期ARB变形,利用光学显微镜(OM)、扫描电子显微镜(SEM)和能谱仪(EDS)研究了Mg/Al多层板材在ARB变形过程中的微观组织,并在拉伸试验机上测试板材的室温抗拉强度并通过扫描电子显微镜(SEM)观察拉伸试验后的断口形貌。结果表明,随着叠轧周期数的增加,Mg/Al多层复合材料层界面处生成并长大的金属间化合物明显细化,该化合物会逐渐呈连续多层状分布,同时也提高了层界面的结合程度。不过,Mg/Al多层复合材料的抗拉强度在叠轧过程中却呈现出不规则的变化趋势。     

Cu/Mo/Cu复合板界面变形及厚度配比

采用热轧+温轧方法制备Cu/Mo/Cu复合板,研究轧制工艺对复合板结合界面及组元厚度配比的影响。结果表明：经过轧制变形后,铜钼界面实现紧密结合且结合机制为齿状啮合,铜层外表面和靠近界面层的晶粒比中部细小;随着变形量的增加,铜层等轴状晶粒沿轧制方向被拉伸,界面结合效果明显改善,且由齿状变得较为平直。分析组元厚度配比,铜层变形量较钼层的大,随着总压下量的增加,组元压下率的差值减小,变形量逐渐趋于一致;首次提出了Cu/Mo/Cu三层复合板厚度配比的关系,为实际选择原料提供依据     

铝/铁复合板与铝合金超声波辅助钎焊

利用超声波辅助钎焊的方法,在大气环境、中温、无钎剂条件下,实现了铝合金与薄膜铝/铁复合板的高强、可靠连接.研究了采用Zn-Al,Al-Si钎料得到的焊缝组织及其性能.结果表明,采用Zn-Al钎料钎焊5A06铝合金和复合板,超声波能有效破除氧化膜,铝膜溶解扩散易于控制,焊缝没有金属间化合物,在铝层未完全溶解时,抗剪强度均大于70 MPa,焊缝由α-Al,η-Zn,共晶和共析组织构成;采用Al-Si钎料钎焊1100纯铝和复合板,复合板铝膜短时间内完全溶解,焊缝存在复杂的Fe-Al-Si三元化合物,并发现明显的裂纹,抗剪强度约为20 MPa.     

溶渗法制备Al3Ti/Al复合材料的研究

以钛丝网为反应源,以金属Al为基体,通过熔渗+原位反应法制备出一种Al3Ti金属间化合物颗粒增强铝基表面复合涂层。根据差热分析结果确定了反应温度为890℃;通过XRD、SEM以及显微硬度和磨损测试对所得到的复合涂层进行了表征。结果表明:当保温时间为20 min时,钛丝在铝基体中的反应较完全,原位合成为块状和条状的Al3Ti颗粒;颗粒的显微硬度大约为基体的4.5倍;在载荷为10 N的干滑动磨损条件下,相对于没有增强的Al基体而言,保温20 min所制备的复合涂层表现出较好的耐磨性,其磨损机制为粘着磨损和磨粒磨损共存。     

Al/Cu/Al接触反应液相行为及其连接

采用模拟的方法,系统研究了Al/Cu接触反应及其液相行为的特点,并运用金属学中表面扩散和晶界扩散等理论进行了理论探讨。研究结果表明,在接触反应中Al/Cu共晶液相的行为包括：一方面液相沿Al基体表面优先反应铺展;另一方面在基体深度方向上也有明显的晶间渗透作用。其中前者可以促进接头间隙内产生均匀的液相填充层;后者则是接头牢固接合的保障。同时为确定Al/Cu/Al接触反应钎焊工艺参数,研究了工艺参数对接触反应中共晶液相铺展行为的影响,结果表明570－580℃的反应温度和15min的保温时间是Al/Cu接解反应钎焊比较适合的工艺参数。在此基础丰,本文采用Cu箔作中间层进行Al的接触反应钎焊,得到良好Al钎焊接头。     

Al/TiC/Al2O3复合结合剂立方氮化硼复合材料的制备

采用Al/C/TiO2/CBN(各组粉体中,CBN质量分数均为10％)粉体为原料,通过原位反应烧结技术,制备Al/TiC/Al2O3金属陶瓷复合结合剂立方氮化硼(CBN)材料.采用X射线衍射(XRD)、扫描电镜(SEM)结合能谱仪(EDS)分析试样.在1100℃保温1h,反应烧结得到Al/TiC/Al2O3金属陶瓷复合结合剂CBN材料.研究结果表明,当采用结合剂组成为4Al/3C/3TiO2的原料(CBN质量分数为10％)时,由于反应放热量较大,导致CBN发生严重的热损伤,CBN都明显断裂.在原料中增加Al的质量分数,可显著降低反应产生的高温,可显著降低热损伤,从而制备不同Al质量分数的Al/TiC/Al2O3金属陶瓷复合结合剂CBN材料.     

ULTRASONIC VIBRATION LIQUID CAST SiC_w/Al AND SiC_p/Al COMPOSITES

SiC_w Al and SiC_p/Al composites have been produced by an uhrasonic vibration casting technique. Ultrasound irradiation promoted the wetting of reinforcements in aluminum liquid, improved the reinforcement distribution in the metal matrix, and reduced porosity. The composites can be remelted. Initial studies of the preparation procedures, microstructure, fracture surface morphology and remelting properties of SiC_w/Al and SiC_p/Al composites fabricated by ultrasonic vibration liquid are presented in this work.     

Reciprocating wear behavior of 7075Al/SiC in comparison with 6061Al/Al2O3 composites

In the present study, the reciprocating wear behavior of 7075Al/SiC composites and 6061Al/Al₂O₃ composites that are prepared through liquid metallurgy route is analyzed to find out the effects of weight percentage of reinforcement and load at the fixed number of strokes on a reciprocating wear testing machine. The Metal Matrix Composite (MMC) pins are prepared with different weight percentages (10, 15 and 20%) of SiC and Al₂O₃ particles with size of 36 μm. Hardness of these composites increases with increase in wt.% of reinforcement. However, the impact strength decreases with increase in reinforcement content. The experimental result shows that the volume loss of MMC specimens is less than that of the matrix alloy. However, the volume loss is greater in 6061Al/Al₂O₃ composites when compared to 7075Al/SiC composites. The temperature rise near the contact surface of the MMC specimens increases with increase in wt.% of reinforcement and applied load. The coefficient of friction decreases with increase in load in both cases.     

In-situ investigation of deformation behavior and fracture forms of Ti/Al/Mg/Al/Ti laminates

In-situ bending and stretching were conducted on hot-rolled and annealed Ti/Al/Mg/Al/Ti laminates, with a focus on crack initiation and propagation of intermetallics and component layers, which helps to clarify their deformation behavior and fracture forms. The results show that delamination is the early fracture form of laminate with or without intermetallics at Al/Mg interface, so Al/Mg interfacial bonding strength determines the mechanical properties of laminate. Various and irregular intermetallics cracks lead to Al/Mg interface delamination in annealed laminate and help to release stress. Necking and fracture of component layers are observed at the late deformation stage, and the sequence is Al, Mg and Ti layers, resulting from their strength. Angle between crack propagation direction and stretching direction of Mg layer both in rolled and annealed laminates is around 45° due to the effect of shear deformation, and crack convergence leads to final complete fracture of Mg layer.     

Asymmetry in interface and bending property of Al/Cu/Al bimetallic laminates

This work was aimed to study the interfacial microstructures and three-point bending properties of Al/Cu/Al bimetallic laminates produced by the asymmetrical roll bonding and annealing. It is found that the microstructure and bonding strength of the Al/Cu interface are different with those of the Cu/Al interface. The interfacial microstructure of Cu/Al interface is improved due to the large interfacial plastic deformation caused by the different rotation speeds of roll in the asymmetrical roll bonding process. The bonding strength between Al and Cu layer can be enhanced by the moderate atomic diffusion, but is dramatically depressed by the formation of intermetallic compounds in the interface.The bending strength of bimetallic laminates is enhanced when the Cu/Al interface is loaded in tension because of the improvement of stress transition and damping by the Cu/Al interface during the three-point bending deformation. The bending fracture reveals that the interfacial cracks can be inhibited from the restricted stress concentration in the improved Cu/Al interface.     

Theoretical model for evaluating the threshold reduction in roll bonding of Al/Al2O3/Al laminations

Roll bonding is the most important stage of the accumulative roll bonding process, which is used to produce high strength composites. The presence of a particle layer at the interface alters the bonding condition and increases the threshold reduction for the commencement of bonding. In this study, the bonding mechanism in presence of powder at the interface is analyzed and a theoretical model is proposed to predict the required threshold reduction in warm roll bonding of commercially pure aluminum sheets as a function of amount of alumina particles at the interface. The model considers the rolling parameters and the effect of amount and size of particles by defining some constants, which are obtained by experiment. It is shown that the measured values of the threshold reduction are very well predicted by the modeling results.     

熔体内原位制备Al3Ti增强铝基复合材料的研究

5Al-Ti体系粉末压坯在铝液中原位反应,经搅拌浇注后制备出Al3Ti颗粒增强的铝基复合材料.分析了5Al-Ti体系粉末的反应过程及热力学,探讨了工艺参数对复合材料微观组织形态的影响及形成机理.研究发现,5Al-Ti体系粉末在850℃预热时,发生剧烈的热爆反应生成Al3Ti;压坯在铝液中预热经搅拌浇注后Al3Ti颗粒在铝基体上呈细小块状和短棒状分布,复合材料硬度随着Al3Ti颗粒含量的增多而提高;合适的搅拌工艺有助于Al3Ti颗粒在铝基体上的均匀分布.