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.     

Fractals in Steel-Aluminum Solid to Liquid Bonding

1.IntroductionSinceBenoitMandelbrotpresefltedfrartalthe-oryinhisbook<>inl977formally,itcanbesaidthatthestudyandapplicationoffractalshadbeencon-ductedinalmosteveryfieldgenerallyformorethan2oyears.On1yformetalfracturefield,greatevolutionandprogresshavebeenacquired,thegeneralrulesarethatalthoughthefracturesurfaceisscraggyandirreg-ular,ithasobviousselfanaloguecharacteristicwhenitisobservedwithinsomerealmofsize[1'2].There-foretheirregularityofthefracturesurfacecan…     

Effect of interlayer thickness on shear deformation behavior of AA5083 aluminum alloy/SS41 steel plates manufactured by explosive welding

An AA5083 aluminum alloy plate and an SS41 steel plate were cladded by an explosive welding method using an AA1050 aluminum alloy interlayer plate. The effects of the interlayer thickness on the interface morphology and the shear deformation behavior of the cladded plates were studied. The interfacial zone was composed of an intermetallic compound, FeAl₃, formed by the AA1050 interlayer. The intermetallic compound acted as a crack source at the AA1050/SS41 interface, and the thickness and morphology of the interfacial zone were depended on the thickness of the AA1050 interlayer. In a shear deformation test, the crack propagation behavior varied according to the morphologies of the interfacial zone, and the shear strength of the cladded plates decreased with the interlayer thickness.     

High temperature interfacial studies in aluminium-stainless steel composites

Interfacial shear strengths in single wire aluminium-stainless steel composites have been measured by the pull-out test, both at room temperature and high temperatures, as a function of annealing temperatures up to 823 K and times up to 24 h. The post-exposure interfacial shear strengths measured at room temperature have been found to be inversely proportional to the square root of the interfacial compound layer thickness. A tentative mechanism to explain this relationship has been proposed in terms of matrix-compound layer debonding. The growth of the compound layer during high-temperature exposure is accompanied by an increase in its microhardness, presumably resulting from a concurrent precipitation of intermetallics. The interfacial shear strength has been found to be independent of stainless steel wire diameter.     

Interfacial Structure of Steel-Mushy Al-20Sn Bonding Plate

Fe-AI compound at the interface of steel-mushy AI-20Sn bonding plate was studied quantitatively. The relationship between ratio of Fe-AI compound at interface and bonding parameters (such as preheat temperature of steel plate, solid fraction of AI-20Sn slurry and rolling speed) was established by artificial neural networks perfectly. The results show that when the bonding parameters are 505℃ for preheat temperature of steel plate, 34.3% for solid fraction of AI-20Sn slurry and 10 mm/s for rolling speed, the reasonable ratio of Fe-AI compound corresponding to the largest interfacial shear strength of bonding plate is obtained. Its value is 72%. This reasonable ratio of Fe-AI compound is a quantitative criterion of interfacial embrittlement, that is, when the ratio of Fe-AI compound at interface is larger than 72%, interfacial embrittlement will occur.     

Semi-solid Pressing Bonding Strength between Steel and Cu-graphite Composite

The pressing bonding of steel plate with QTi3.5-3.5graphite slurry was studied. The relationship among preheating temperature of steel plate, preheating temperature of dies, solid fraction of QTi3.5-3.5graphite slurry, and interfacial shear strength of bonding plate could be established with artificial neural networks perfectly. This model could be optimized with a genetic algorithm. The results show that the optimum bonding parameters are: 618℃ for preheating temperature of steel plate, 526℃ for preheating temperature of dies and 46.2% for solid fraction of QTi3.5-3.5graphite slurry, and the largest interfacial shear strength of bonding plate is 128.3 MPa.     

Study on Steel-Mushy Al-20Sn Alloy Bonding

Steel-mushy Al-20Sn alloy bonding was studied for the first time. The relationship model about preheat temperature of steel plate, solid fraction of Al-20Sn alloy mushy, rolling speed and interfacial shear strength of bonding plate could be established by artificial neural networks perfectly. This model could be optimized with a genetic algorithm. The optimum bonding parameters were: 505℃ for preheat temperature of steel plate, 34.3% for solid fraction of Al-20Sn alloy mushy and 10 mm/s for rolling speed, and the largest interfacial shear strength of bonding plate was 71.2 MPa.     

Influence of Pressing Time on Steel-copper-graphite Bonding

The bonding of steel plate with QTi3.5-3.5 graphite slurry was studied by using pressing bonding technique. The influence of pressing time on the interracial mechanical property of bonding plate was researched. The results show that： under the conditions of 620℃ preheating temperature of steel plate, 530℃ preheating temperature of dies, 46% solid fraction of QTi3.5-3.5 graphite slurry and 50 MPa pressure, there exists a nonlinear relationship between pressing time and interracial shear strength. The interracial shear strength of bonding plate increases with increasing pressing time and reaches a largest value about 127 MPa when pressing time is longer than 120 s. At the interface with the best mechanical property, there exists a continuous Fe-Cu inter-diffusion zone and a metallurgical bonding.     

多层金属复合板的热轧制备方法

提高成材率和复合界面质量是制备多层复合板的难题。本工作提出一种多层复合板的高成材率热轧制备方法,即采用氩弧焊固定各层原料板组成坯料,坯料放入金属套后抽真空,再加热到1000~1200℃进行多道次轧制,成功制备出2.5mm厚的67层复合板。通过金相显微镜及电子显微镜观察和分析了界面组织及元素扩散行为,采用拉伸、剪切实验测定复合板的力学性能,并分析其剪切断口。结果表明:采用两步组坯复合和工艺优化,多层复合板的轧制成材率达90%以上。多层复合板具有良好的结合界面,其抗剪强度达到241MPa。9Cr18和1Cr17镍中间层可以较为有效地阻碍界面附近的碳扩散并改善复合板的组织特征。     

碳纳米管纤维/环氧树脂复合材料的界面剪切强度及微观结构

研究了碳纳米管纤维的微观结构和拉伸性能,并进一步分析了其与环氧树脂形成界面剪切强度及微观结构。采用单丝断裂试验测试了碳纳米管纤维/环氧树脂复合材料体系的界面剪切强度,结合单丝断裂过程中的偏光显微镜照片、复合材料的拉曼谱图和断口扫描电镜照片,研究了碳纳米管纤维/环氧树脂复合材料界面的微观结构。结果表明: 碳纳米管纤维/环氧树脂复合材料的界面剪切强度约为14 MPa;在碳纳米管纤维和环氧树脂形成界面的过程中,环氧树脂可以浸渍纤维,形成具有一定厚度的复合相,这种浸渍过程和界面相的形成都有利于碳纳米管纤维与基体之间的连接。     

Influence of Diffusion Time on Steel—Aluminum Solid to Liquid Bonding Interfacial Structure

The bonding of steel plate to aluminum liquid was conducted using rapid solidification. The influence of diffusion time on interfacial structure was studied. The results showed that under the condition of 750(C) for the temperature of aluminum liquid and 200(C) for the preheat temperature of steel plate, when diffusion time was shorter than 4.3 s, there was only Fe-AI solid solution at the interface. When diffusion time was longer than 4.3 s, Fe-AI compound began to form at the interface. The relationships between diffusion time t and thickness of Fe-AI compound layer H are H=-9.72+2.62t-0.08t2 (4.3 s15 s).     

钢-Al-20Sn复合板的非均匀扩散复合研究

提出了消除钢-Al-20Sn复合板复合界面脆化的非均匀扩散思想,并采用Al-20Sn半固态浆料与钢板进行铸轧复合,实现了非均匀扩散,改变了复合界面结构,消除了复合板复合界面的脆化。研究结果表明,在500℃钢板预热温度、10mm/s铸轧速度条件下,当半固态浆料固相率为34.3%时,复合界面由比例恰当的铁铝化合物和铁铝固溶体交替构成,脆化得以消除,相应的最大界面剪切强度为69.9MPa。     

Fe/Al异质金属接头界面组织演变、生长动力学及力学性能

采用真空扩散连接方法研究Fe/Al异质金属接头界面组织演变规律、金属间化合物(intermetallic compound,IMC)生长动力学及力学性能。结果表明：焊接温度为550 ℃时,接头界面无IMC生成,当焊接温度超过575 ℃时,界面由Fe₂Al₅及少量FeAl₃ IMC构成,且随焊接温度升高IMC层迅速长大。在120 min保温时间条件下,接头剪切强度随焊接温度的升高先增加后降低,当焊接温度为575 ℃时,接头剪切强度达到最大值37 MPa。在550~625 ℃范围内,基于热力学分析得出Fe₂Al₅的吉布斯自由能ΔG_Fe-Al最低,而FeAl₃的ΔG_Fe-Al次之,在接头界面处IMC生成顺序为Fe₂Al₅→FeAl₃。Fe/Al接头界面IMC的生长随焊接温度呈抛物线规律,其生长激活能为282.6 kJ·mol^-1。在575,600,625 ℃条件下,界面IMC的生长速率分别为1.13×10^-14,3.59×10^-14,1.21×10^-13 m²·s^-1。     

不同缓蚀剂对SnAgCu焊膏焊接性能的影响

通过对SnAgCu焊膏/Cu焊接界面IMC层和力学性能进行分析,研究了助焊剂中添加咪唑类缓蚀剂A和喹啉类缓蚀剂B及其复配对SnAgCu焊膏焊接性能的影响.利用扫描电镜(SEM)和能量色散谱仪(EDS)分别对IMC层的微观结构和焊点的组织成分进行观察和分析,采用力学试验机测试焊点的剪切强度和拉伸强度,并通过SEM观察其断口形貌.研究结果表明:缓蚀剂对界面IMC层的生长起到一定控制作用,不添加任何缓蚀剂时,IMC层厚度不均匀,部分呈粗大的柱状结构,平均厚度为7.6μm;而添加0.5%A和0.5%B复配缓蚀剂的焊膏,IMC层最薄而且致密均匀,厚度为3.4μm;添加0.5%A和0.5%B复配缓蚀剂的焊膏,获得了最大的剪切强度和抗拉强度,其中剪切强度为47.92 MPa,剪切断裂模式为韧性断裂,抗拉强度为99.28 MPa,拉伸断裂模式为脆性断裂.     

Interface layer effect on the stress distribution of a wafer-bonded bilayer structure

The interface layer plays an important role in stress transfer in composite structures. However, many interface layer properties such as the modulus, thickness, and uniformity are difficult to determine. The model developed in this article links the influence of the interface layer on the normal stress distribution along the layer thickness with the layer surface morphology before bonding. By doing so, a new method of determining the interfacial parameter(s) is suggested. The effects of the layer thickness and the surface roughness before bonding on the normal stress distribution and its depth profile are also discussed. For ideal interface case with no interfacial shear stress, the normal stress distribution pattern can only be monotonically decreased from the interface. Due to the presence of interfacial shear stress, the normal stress distribution is much more complex, and varies dramatically with changes in the properties of the interface layer, or the dimensions of the bonding layers. The consequence of this dramatic stress field change, such as the shift of the maximum stress from the interface is also addressed. The size-dependent stress distribution in the thickness direction due to the interface layer effect is presented. When the interfacial shear stress is reduced to zero, the model presented in this article is also demonstrated to have the same normal stress distribution as obtained by the previous model, which does not consider the interface layer effect.     

Effect of Relative Reduction on Property of Steel-Mushy Cu-Graphite Composite

The rolling treatment of steel-mushy QTi3.5-3.5 graphite composite was conducted under different relative reduction at room temperature. The effect of room-temperature rolling on interfacial mechanical property of steel-mushy QTi3.5-3.5 graphite composite was studied and the relationship between interfacial shear strength and relative reduction was established. The results show that, for steel-mushy QTi3.5-3.5 graphite composite, which consists of 1.2 mm-thick 08AI steel plate and 2.8 mm-thick QTi3.5-3.5 graphite layer, there is a nonlinear relationship between interfacial shear strength and relative reduction in graphite layer. When relative reduction is smaller than 1.1%, interfacial shear strength increases with increasing the relative reduction. When relative reduction is larger than 1.1%, interfacial shear strength decreases with increasing the relative reduction. When relative reduction is 1.1%, the largest interfacial shear strength of 145.2 MPa can be obtained.     

Interfacial microstructure and shear strength of Ti–6Al–4V/TiAl laminate composite sheet fabricated by hot packed rolling

A two layer Ti–6Al–4V(wt.%)/Ti–43Al–9V–Y(at.%) laminate composite sheet with a uniform interfacial microstructure and no discernible defects at the interfaces has been prepared by hot-pack rolling, and its interfacial microstructure and shear strength were characterized. Characterization of the interfacial microstructure shows that there was an interfacial region of uniform thickness of about 250 μm which consisted of two layers: Layer I on the TiAl side which was 80 μm thick and Layer II on the Ti–6Al–4V side which was 170 μm thick. The microstructure of Layer I consisted of massive γ phases, needlelike γ phases and B2 phase matrix, while the microstructure of Layer II consisted of α₂ phase. The microstructure of the interfacial region is the result of the interdiffusion of Ti element from Ti–6Al–4V alloy layer into the TiAl alloy layer and Al element from the TiAl alloy layer into the Ti–6Al–4V alloy layer. The shear strength measurement demonstrated that the bonding strength between the TiAl alloy and Ti–6Al–4V alloy layers in the laminate composite sheet was very high. This means that the quality of the interfacial bonding between the two layers achieved by the multi-path rolling is high, and the interface between the layers is very effective in transferring loading, causing significantly improved toughness and plasticity of the TiAl/Ti–6Al–4V laminate composite sheet.     

Multi-scale shear properties of flax fibre reinforced polyamide 11 biocomposites

Multiscale analyses are carried out to evaluate and understand the shear properties and behaviour of a flax fibre reinforced polyamide 11 (PA 11) biocomposite. Tensile tests of [±45]_n laminates are performed to evaluate the macroscale in-plane shear properties, while microbond tests are performed to evaluate the apparent interfacial shear strength. Although the shear stiffness of PA 11 biocomposites is lower than the available literature values, the shear strength is higher due to a relatively high interfacial bonding strength. Flax/PA 11 interfacial bonding is controlled by hydrogen bonding rather than adhesive pressure induced by residual thermal stress. A superficial fibre cell-wall layer (primary cell-wall) is observed at different scales, which highlights the contribution of the global structure of flax fibres to the shear properties of biocomposites.     

累积叠轧焊过程中的材料界面焊合

累积叠轧焊(ARB)工艺可以制备超细晶、高性能、大尺寸的金属及合金板材,具有自身突出的优越性,容易实现工业化生产,是目前剧塑性变形工艺领域的研究热点之一。ARB变形金属层间的界面焊合强度是影响其工艺及材料工业应用的主要因素之一。本文对累积叠轧焊工艺的界面焊合特点进行了综述,对道次变形量、ARB变形前后退火工艺、板材表面处理等因素对ARB板材界面焊合性能的影响进行深入分析。同时简要介绍了板材界面焊合质量的表征方法。     

碳/铝复合材料界面反应对抗拉强度的影响

本文对Ti-B法制备的碳—铝合复材料经各种处理后产生的不同程度的界面反应与其纵向抗拉强度的关系进行了研究。碳—铝界面反应主要从三方面影响复合材料的抗拉强度:①界面结合强度;②界面脆性层;⑨纤维损伤。这三者的作用程度与界面反应程度有关。界面反应不严重时,主要是界面结合强度起作用;反应较严重时,界面脆性层的影响增大;反应很严重时,纤维发生严重损伤,对材料的抗拉强度产生很大的影响。