基于界面影响区特征的铜/铝复合板损伤行为研究

目的 基于Cohesive–GTN模型建立考虑了界面影响区的铜/铝复合板有限元损伤模型,研究铜/铝复合板塑性变形的损伤演化行为,精细化分析金属层状复合板的损伤机理。方法 采用拉伸试验机、显微硬度计、EDS能谱仪、扫描电镜等测试手段,结合试验模拟,将获取的参数输入ABAQUS有限元软件中并对模拟结果进行研究分析。结果 基于试验法确定了界面区的宽度约为3 μm,铜侧界面影响区宽度约为50 μm,铝侧界面影响区宽度约为100 μm。当塑性变形量逐步增加时,铜层材料较早发生损伤断裂,之后铝层进入集中失稳阶段,主裂纹贯穿铝层直至复合板材料整体发生断裂。此外,各异质层材料内部孔洞的体积分数不断增大,达到材料失效时的孔洞体积分数,材料发生损伤失效。结论 基于Cohesive–GTN模型建立考虑了界面影响区的铜/铝层状复合板有限元损伤模型,并结合试验验证了模型的合理性和可靠性。在考虑了界面影响区的基础上,研究了铜/铝复合板塑性变形损伤演化行为,揭示了铜/铝复合板塑性变形损伤机制,为后续金属复合板的损伤分析提供更为精细化的建模方法。     

铸轧铜铝复合板界面演变规律研究

采用铸轧法制备了铜铝复合板,利用光学显微镜、扫描电镜和X射线衍射仪等分析手段考察了界面微观形貌和物相成分,分析了轧制和退火过程中界面的演变过程。结果表明,热处理过程中的界面演变过程主要包括过饱和固溶体形成、金属间化合物形核析出、金属间化合物沿界面横向相连、界面层增厚四个阶段。剥离过程中界面沿CuAl_2层开裂,随着退火时间的延长,剥离面形貌由撕裂棱和沟槽转变为撕裂平台和裂纹。轧制过程中界面层发生脆性断裂,纯铜和纯铝挤入裂缝形成直接接触区域。随着轧制压下率的增大,铜铝直接接触区域所占比例增大,破碎的界面层以尺寸较小的碎块状嵌在纯铜和纯铝之间,且碎块与界面之间呈一定夹角分布。     

钛网添加对镁/铝复合板微观组织和力学性能影响研究

目的 有效抑制镁/铝复合板界面处金属间化合物的形成。以钛网为中间金属夹层,研究它对镁/铝复合板微观组织和力学性能的影响。方法 利用复合轧制技术制备以钛网为中间金属夹层的镁/铝-钛复合板,采用扫描电子显微镜(SEM)、电子背散射衍射仪(EBSD)、万能试验机等对复合板退火前后的微观组织和力学性能进行表征和分析,系统研究中间层钛网对轧制态和退火态复合板微观组织、织构、拉伸性能、界面结合强度的影响规律。结果 中间层钛网均匀分布在镁/铝-钛复合板界面处,钛网的添加能有效抑制复合板退火过程中镁-铝金属间化合物的连续生长,减少金属间化合物的数量。与镁/铝复合板相比,钛网的添加对轧制态和退火态复合板中镁层和铝层的平均晶粒尺寸和织构类型的影响较小。与镁/铝复合板相比,钛网的添加降低了轧制态复合板的界面剪切强度和延伸率,但极大提升了退火态复合板的界面剪切强度、拉伸强度和延伸率。结论 中间层钛网的添加可有效减少复合板界面处金属间化合物的数量,提升退火态复合板的综合力学性能。     

铝/钢轧制复合有限元二次开发模拟与实验研究

目的 针对铝/钢两种金属性能差异大,轧制复合存在严重的变形不协调及结合强度低的问题,研究轧辊同径与异径及单辊驱动对复合板协调变形及结合强度的影响.方法 通过有限元二次开发进行模拟建模,并结合同步和异步轧制实验分析板翘曲机理.结果 与铝板接触的轧辊作为主驱动辊可使板变形更协调且结合强度更高,变形翘曲度为0.048,结合强度为34.2 MPa.结论 采用接触铝侧轧辊单侧驱动,双金属界面实现复合的位置更靠近轧辊出口,复合后的双金属界面间的剪应力和所受弯矩较小,制备的铝/钢复合板变形协调性更好,且结合强度更高.     

冷轧成形钛/钢层状复合板界面结合强度的影响因素EI北大核心CSCD

采用冷轧复合法制备钛/钢层状复合板,研究轧制压下率、轧制道次、表面粗糙度、原材料状态和轧制速率对钛/钢层状复合板界面结合强度的影响。结果表明:界面作用力和轧制力对界面的作用时间是影响钛/钢层状复合板界面结合强度的主要因素。轧制压下率、表面粗糙度和原材料状态通过影响界面作用力来影响钛/钢层状复合板的界面结合强度;轧制速率通过影响轧制力对界面的作用时间来影响钛/钢层状复合板的界面结合强度;钛/钢层状复合板的冷轧复合效果与轧制道次无关,只有单道次轧制压下率超过临界轧制压下率时,才能实现冷轧复合。     

异步轧制对钢/铝复合板组织与性能的影响

采用金相显微镜、扫描电镜及材料拉伸试验机等研究了异步轧制工艺制备的钢/铝复合板的组织与性能,探讨了异步速比对复合板界面剪切强度的影响。结果表明,异步轧制工艺可在30%的临界压下率下实现钢/铝的有效初结合,板材的初结合强度高于同步轧制样品。复合板的界面剪切强度随异步速比的增加先增大后减小,最佳的异步速比为1.2～1.25。异步轧制过程可实现钢基体粗大柱状晶的破碎与晶粒细化,轧后的复合板在450℃退火1h后即可以使钢基体获得理想的软化效果,克服了同步轧制样品在温度超过500℃退火时界面易生成脆性金属间化合物的难题。复合板的反复弯曲次数可达10次。     

电子封装用Cu/Mo/Cu复合材料的工艺研究

研究了浸涂助复剂(铝基合金)和室温轧制工艺对Cu/Mo/Cu复合界面结合强度的影响,简述了Cu/Mo/Cu复合板室温轧制成形工艺过程,详细分析了表面和界面清理、初道次轧制临界变形率及热处理工艺等因素对复合板结合强度的影响.实验结果得出,钼板浸涂Al-Mn-Zn-Sn合金助复剂后的热处理温度为800～850℃;初道次轧制变形率为45%最佳;复合轧制后合适的退火工艺为450℃,保温60 min.     

1Cr18Ni9Ti-20G爆炸焊接+轧制工艺研究

为了研究在不同爆炸焊接工艺条件下获得的复合板的轧制效果,本文对大波、小波、微波状3种界面的1Cr18Ni9Ti／20G复合板进行轧制实验研究．实验表明：只有用下限获得的微小波状界面的爆炸焊接复合板,才能实现成功轧制,而大波状复合板界面存在一定的缝隙、空洞等微观缺陷,在轧制时由于分层会使轧制失效．爆炸焊接 轧制工艺获得的复合板结合界面的组织、强度和性能的测试结果表明：轧制复合板结合界面的剪切和分离强度虽比爆炸态略低,但延伸率、冲击韧性都大大增强,轧制复合板的耐蚀性能也未降低．     

表面织构与复合板联合轧制成形的数值模拟研究

目的研究结合界面带微织构的复合板的轧制成形过程。方法基于Deform软件,以CDA-377铜和1100铝复合板为研究对象,模拟铜板表面微织构加工过程以及带微沟槽的铜板与铝板的轧制复合过程,分析整个轧制复合过程中轧制力的变化规律,然后在复合板稳定轧制过程中对板料金属单元进行样点追踪以及应力分析,最后以铝板温度、压下率为变量,分析铝板温度、压下率对稳定轧制阶段轧制力的影响。结果通过改变铝板温度和压下率进行多次模拟,发现铝板温度为200℃,压下率为25%时,在整个复合轧制过程中,咬入阶段轧制力先上升到最大值608 N,随后下降并稳定在366 N左右,并进入稳定轧制阶段;在稳定轧制过程中,铝板基层和凹陷层的应力变化规律基本一致,应变主要集中在铝板一侧;随着铝板温度升高、压下率降低,稳定轧制阶段的轧制力呈下降趋势。结论微织构复合板轧制过程中轧制力的变化规律、稳定轧制状态下的轧制力受温度和压下率影响的机理与普通复合板基本一致,而稳定轧制状态下结合界面的应力变化规律与微织构相关。     

T2纯铜/2024铝合金爆炸焊接接头界面结构及性能

为研究铜铝异种金属爆炸焊接头界面形成机理,采用爆炸焊对T2纯铜和2024铝合金进行了焊接.通过光学显微镜、扫描电镜、X射线衍射、万能材料试验机和纳米压痕仪,对T2/2024复合板结合界面的显微组织、成分分布和力学性能进行了测试分析.结果表明:T2/2024合金爆炸复合板结合界面呈波状结合,结合界面主要由平直界面、波状界面和局部熔化层界面构成;靠近结合界面处,基体金属发生塑性变形,晶粒细化;反应层主要成分为AlCu和Al_2Cu的混合物.复合板拉剪试验表明,T2/2024合金爆炸复合板平均结合强度为67 MPa,纳米压痕测试反应层平均硬度可达8 GPa.     

High‐performance Cu/Al laminated composites fabricated by horizontal twin‐roll casting

Horizontal twin‐roll casting technology was successfully introduced to produce high‐performance copper/aluminum (Cu/Al) laminated composites. The interface morphology, electrical properties and peeling strength after different annealing and cold rolling processes were investigated and contrasted with Cu/Al clad plates fabricated by conventional methods. The results show that sound metallurgical bonding between the copper and aluminum matrix can be attained after the horizontal twin‐roll casting processes and Al₂Cu is the only intermetallics at the interfacial region, the thickness of interfacial interlayer is about 0.7 μm. The peeling strength is 31.4 N/mm and can be further increased to 37.1 N/mm after annealing at 250 °C. However, higher temperature like 400 °C will cause the excessive growth of intermetallics so that peeling strength sharply decreases to 9.2 N/mm. Electrical conductivity of the clad plate is 51 MS/m. At the same electrical current intensity, the temperature‐rise of the composite plate is between the pure copper plate and the aluminum plate, and closer to the copper plate. All of the properties are outstanding than that of Cu/Al clad plate fabricated by conventional methods.     

磁屏Cu-Fe-Cu叠层材料的轧制复合

选用电工纯铁与无氧铜两种组元材料, 采用轧制复合工艺制备了Cu-Fe-Cu磁屏叠层材料, 对轧合件进行力学性能分析, 并运用金相显微镜、 扫描电镜、 能谱仪等手段分析复合件界面形貌及复合机制。结果表明: 采用50%热轧压下率可使铜、 铁板有效复合, 轧合件内各叠层厚度尺寸稳定、 叠层间平行度良好, 经简单退火后其叠层间无明显扩散发生, 叠层间抗剪切强度达167 MPa, 此时热轧的主要复合机制为机械啮合。     

Rolling strain effects on the interlaminar properties of roll bonded copper/aluminium metal laminates

Metal laminates of copper/aluminium were prepared by roll bonding at 430°C with various rolling strains. The effect of the rolling strain on the interface development and bond strength of the laminates was examined. It was found that as the rolling strain increased the bond strength of the laminates was generally enhanced in both as-rolled and sintered conditions. Critical post-rolling sintering conditions were found to exist for achieving optimum bond strengths of the laminates. It is evident that the development of optimum strength for the laminates is related to the formation of various intermetallic phases at the interface which is in turn determined by the diffusion activity of the metallic elements in the area. The greatest strength enhancement was generally observed to develop in the 60% rolled samples, suggesting that rolling strain of the roll bonding process may impose great influence on diffusion of the metallic elements. A higher copper content, without significant Kirkendall void formation, was found to build up in the interface area of the material, leading to development of strong interfacial phases. It is believed that a higher rolling strain of the roll bonding process has provided a greater area of physical contact between the bonded metals and imposed diffusion enhancement of the metallic elements across the interface.     

Fabrication of Al–Cu laminated composites by diffusion rolling procedure

Abstract

A diffusion rolling procedure was employed for the fabrication of Al–Cu laminated composites; the microstructure and mechanical properties of the interface were investigated. With diffusion bonding initially, intermetallic compounds (IMCs) occurred at the Al/Cu interface. After plastic deformation by rolling the laminated composites, the interface strip of IMCs broke and became discontinuous equiaxed particulates. Compared with roll bonding with heat treatment and diffusion bonding, the shear tensile strength of two-stage processed Al/Cu interface reached a maximum value equivalent to 90% of that of Al. Therefore, it is concluded that the diffusion rolling procedure yielded the highest strength of Al–Cu laminated composites.     

镁/铝双金属复合材料成形工艺的研究进展及影响结合层的因素

镁合金和铝合金具有密度低、比强度高等特点,在汽车轻量化方面具有显著优势。Mg/Al双金属复合材料兼具2种金属的优点,在运输、电子3C等领域具有广泛的应用前景。制备Mg/Al复合材料的方法可分为焊接、铸造、轧制和挤压4大类。在制备Mg/Al复合材料时,4种方法均会不可避免地在界面结合处产生硬脆相的金属间化合物(IMC),如Al3Mg2、Al12Mg17等。硬脆相的IMC往往不利于Mg/Al之间的结合。提高Mg/Al双金属复合材料结合强度的关键是消除或者减少IMC。针对以上问题,综述了目前较为前沿的焊接、铸造、轧制、挤压等用于制备Mg/Al双金属复合材料的新工艺,分析了不同工艺及其参数、夹层合金元素、界面形状对结合层组织和性能的影响。最后,对目前制备Mg/Al复合材料成形工艺的研究现状进行了总结与展望。     

Characterisation of steel/nickel bronze clad strips prepared by continuous solid/liquid bonding method

A continuous solid/liquid bonding method was successfully developed to fabricate Cu–10wt-%Ni–1wt-%Fe (nickel bronze) clad steel with a good metallurgical bonding in the present study. The results indicated that the diffusion distance of interface is about 1.90–2.18?µm. The average tensile shear strength of centre composite strip at as-cast state is 228?±?5?MPa, while that of edge is 202?±?6?MPa, and the interface strength is higher than that of bronze since the fracture always occurs on the nickel bronze side. After the rolling process, the tensile shear strength increases with the increasing rolling reduction. The reason can be ascribed to the strengthening of the nickel bronze whose strength is still lower than the interface.     

Influence of Rolling Treatment on Interfacial Shear Strength of Steel-mushy Al-7graphite Bonding Plate

At room temperature, the rolling treatment of steel-mushy Al-7graphite bonding plate was carried out under different relative reduction. The influence of rolling on interfacial mechanical property of this bonding plate was studied. The results show that, for steel-mushy Al-7graphite bonding plate which is made up of 1.2 mm in thickness 08AI steel plate and 2.0 mm in thickness Al-7graphite layer, there is a nonlinear relationship between interfacial shear strength of bonding plate and relative reduction of rolling. When relative reduction of rolling is smaller than 2.59%, with the increasing of relative reduction, interfacial shear strength of bonding plate increases gradually. When relative reduction of rolling is bigger than 2.59%, with the increasing of relative reduction, interfacial shear strength of bonding plate decreases continuously. When relative reduction of rolling is 2.59%, the largest interfacial shear strength 77.0 MPa can be obtained.     

铝/氮化铝电子陶瓷基板的制备及性能的研究

在675～750℃、氮气气氛下,使用石墨模具压铸的方法将金属纯Al敷接在AlN电子陶瓷基板上,随后利用力学拉伸试验机测试了Al和AlN的结合强度,其界面抗拉强度>15.94MPa,然后使用金相显微镜、SEM等微观分析仪器研究其界面的微观结构,发现在Al/AlN界面没有任何新物质生成,金属铝晶粒直接在AlN陶瓷表面结晶长大.     

铝和氮化铝陶瓷结合强度与机理研究

在氮气气氛下、保温10min、948~1098K利用活性金属铸接方法制备铝/氮化铝陶瓷基板, 用力学试验机、扫描电子显微镜、高温金相光学显微镜和原子力显微镜对铝/氮化铝陶瓷的结合强度和机理进行研究. 结合温度低于973K时, 铝和氮化铝陶瓷之间的剥离强度随结合温度升高线性增大, 当结合温度超过973K时, 结合温度对强度影响很小, 铝和氮化铝陶瓷之间的结合强度约为49N/mm, 铝和氮化铝陶瓷之间的结合为物理湿润和化学反应湿润共同作用.     

Improvement of Joint Strength of SiCp/Al Metal Matrix Composite in Transient Liquid Phase Bonding Using Cu/Ni/Cu Film Interlayer

The compact oxide on the surface of SiCp/Al metal matrix composite （SiCp/Al MMC） greatly depends on the property of the joint. Inlaid sputtering target was applied to etch the oxide completely on the bonding surface of SiCp/Al MMC by plasma erosion. Cu/Ni/Cu film of 5μm in thickness was prepared by magnetron sputtering method on the clean bonding surface in the same vacuum chamber, which was acted as an interlayer in transient liquid phase （TLP） bonding process. Compared with the same thickness of single Cu foil and Ni foil interlayer, the shear strength of 200 MPa was obtained using Cu/Ni/Cu film interlayer during TLP bonding, which was 89.7% that of base metal. In addition, homogenization of the bonding region and no particle segregation in interfacial region were found by analysis of the joint microstructure. Scanning electron microscopy （SEM） was used to observe the micrograph of the joint interface. The result shows that a homogenous microstructure of joint was achieved, which is similar with that of based metal.