Authors: Friedrich Wilhelm Bach, A. Beniyash, K. Lau, R. Versemann
Abstract: Against the background of the required weight reduction in transportation through
lightweight construction, the application of hybrid structures, where dissimilar materials are joined together, has a high technical and economical potential. In the field of sheet machining, combinations of steel and aluminium are especially interesting. In comparison to conventional steels, the application of aluminium alloys as supporting materials makes a distinct weight reduction possible. On the other hand, steels have advantages in the fields forming and welding. The application of modern high-strength steels with reduced sheet thicknesses allows weight reduction,
too. But joining of material combinations of steel and aluminium is problematic. On the one hand brittle intermetallic compounds are formed between steel and aluminium. On the other hand the aluminium melt has a bad wetting behaviour. Different physical properties of both materials have to be considered, too. To achieve sufficient mechanical properties of such joinings it is necessary to limit growth of intermetallic compounds between steel and aluminium. This can be actualized by an exact energy
supply. With the electron beam on atmosphere a precise and easily controllable energy supply is possible. The publication demonstrates successful investigations, which were performed with the 175 kVNVEBW (Non Vacuum Electron Beam Welding) installation at Institut of Materials Science, University of Hanover. With NVEB joining hybrid structures between zinc coated steels and 5.xxx and 6.xxx aluminium alloys were produced. In a welding-brazing process (the steel remained in the solid phase whereas the aluminium was molten) combinations with acceptable mechanical properties could be joined. By use of optimized joining parameters as well as a surface activating flux, both, a good wetting and a thin intermetallic compound < 10 µm were attained. Another possible strategy is a pure brazing process, for which an example is also given in the paper. The paper shows metallurgical and mechanical investigations, among other things results of element
distribution analysis and tensile tests.
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Authors: Karl Heinz von Zengen
Abstract: Use of aluminium in modern cars has increased during the past 50 years due to the good
properties of the metal and the need for light weighting cars. The permanent rise in energy costs
and need for reduction of emissions world wide make aluminium more and more attractive for
automotive use. Nevertheless, additional costs for light weighting must remain affordable –
materials scientists and process engineers are challenged to meet these requirements.
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Authors: Y. Abe, T. Kato, Kenichiro Mori
Abstract: The aluminium alloy and mild steel sheets were joined with mechanical clinching.
Deforming behaviour of the two sheets during the clinching was observed from finite element
simulation and an experiment to avoid defects. The fracture of the upper sheet, necking and
separation are caused by the small upper sheet thickness in the thick total thickness, the small lower
sheet thickness in the thick total thickness and the small lower sheet thickness, respectively. The
joining range for the combination of the upper aluminium alloy sheet of and the lower steel sheet of
is larger than that of the reverse combination. The effect of the difference between the flow stresses
of the two sheets on the deformation behaviour was examined.
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Authors: Michael F. Zaeh, Paul Gebhard, Sonja Huber, Markus Ruhstorfer
Abstract: On a global market, new products are subject to rising requirements regarding strength and quality.
Simultaneously, the conservation of the environment and natural resources has become a key
priority. One approach to these demands is the weight reduction of mechanical components by
lightweight construction. The Transregional Collaborative Research Center (TR 10), funded by the
German Research Foundation (DFG), is therefore working on the “Integration of forming, cutting
and joining for the flexible production of lightweight space structures”. The use of light metals, like
aluminium and composite materials is a main part in the TR10 process chain. This paper deals with
the challenges of welding of light weight components made out of EN AW-6060. It shows the use
and potentials of two innovative joining processes, particularly suited for welding aluminium.
Especially developed for the fusion welding of aluminium components, BHLW (Bifocal Hybrid
Laser Beam Welding), combines a Nd:YAG and a high power diode laser. The paper will give
insight into the findings of the achieved results so far and line out the further proceedings with
regard to critical parameters and their effect on the overall laser welding process. For the welding of
aluminium composite materials, which play a big role in the TR10 process chain, Friction Stir
Welding (FSW) is evaluated. As a solid state joining process, it can be used for the welding of
materials that are hardly weldable with fusion welding techniques. In this paper, results of basic
experiment for the joining of reinforced aluminium and the resulting process forces are presented.
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Authors: Prakash J. Udaya, T.V. Moorthy
Abstract: The aim of this research work is to study the influence of wear parameters on the adhesive wear behaviour of aluminium matrix composites (AMCs). It consists of A413 aluminium alloy as the matrix material and particulate fly ash of 3%, 6% and 9% by weight as the reinforcement material. Stir casting technique was used to fabricate the AMCs. The distribution of the fly ash particles in the matrix phase was investigated using the SEM image. The wear tests have been carried out using a pin on disc machine according to the ASTM G99 – 05 specifications. Wear surfaces were analysed using the images captured through Video measuring machine. It was found that load has the highest influence on wear rate followed by sliding distance, sliding speed, and weight percentage of reinforcement.
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