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TY  - THES
AU  - Oberschelp, Christian
TI  - Hybride Leichtbaustrukturen für den Karosseriebau - gusswerkstofforientierte Anwendungsuntersuchungen für das Druckgießen
VL  - 9
CY  - Aachen
PB  - Gießerei-Institut der RWTH Aachen
M1  - RWTH-CONV-143803
SN  - 978-3-9813872-8-5
T2  - Ergebnisse aus Forschung und Entwicklung / Gießerei-Institut der RWTH Aachen
SP  - 237 S. Ill., graph. Darst.
PY  - 2013
N1  - Zsfassung in dt. und engl. Sprache
N1  - Zugl.: Aachen, Techn. Hochsch., Diss., 2012
AB  - There is a general demand to decrease the weight of vehicles. This fact has to be considered by current and future body concepts. State of the art car body concepts require a high structural performance combined with a low weight of the component. This demand can be met by hybrid parts, which offer the advantage of a material mix, combining the advantageous properties of the composite partners. The high freedom of construction and geometric shape in primary shaping processes enables joining sheet metal structures to a complex cast structure stiffening the hybrid component and increasing the structural performance.The topic of this paper is to identify casting alloys, steel sheets and steel sheet coatings which enable the production of high quality hybrid structures for body applications in wet area. Therefore the materials have to achieve defined requirements.Casting alloys which have to be used for thin wall hybrid structures need to have a very well castability, a good corrosion resistance, good mechanical properties including a good ductility and a good weldability. To save costs and to reduce residual stress in hybrid components alloys have to be used which show a self-hardening effect. Because of stiffening the hybrid component an almost defect-free casting component is needed. Therefore casting alloys which have been used for composite castings have to show a good castability. The casting alloys AlMg5Si2Mn and AlSi9Mn seem to have the potential to achieve these require-ments. A comparison of both alloys showed that the alloy AlSi9Mn has some advantages over the alloy AlMg5SiMn. The alloy has a higher castability and causes less residual stress in hybrid components. Casting ribs which are given to stabilize hybrid structures often show characteristic shrinkage porosity with a thread-shaped morphology when the alloy AlMg5Si2Mn was used. A higher residual stress caused by the alloy AlMg5Si2Mn is believed by the alloys higher thermal expansion coefficient. Because of the advantages of the alloy AlSi9Mn towards the alloy AlMg5Si2Mn the alloy AlSi9Mn was preferred for the production of hybrid components. Beside the choice of a casting material the micro-alloyed steel ZStE 420 was chosen. This steel material is often used for crash relevant structure parts and shows in combination with coatings a good corrosion resistance. Furthermore the micro-alloyed steel shows a hot temperature resistance for short term which is important when the steel material gets into contact with the molten casting alloy.Using hybrid parts in wet area both materials, casting and steel alloy, need to show a good corrosion resistance itself. To avoid contact corrosion it is necessary that a corrosion current between both materials cannot take place. Therefore it can be very helpful to realize a complete metallic continuity between both materials. To create a metallic continuity a sufficient diffusion time between the material partners is needed. Using technical casting processes like the high pressure die casting process there is only a very limited solidification time and therefore a very limited diffusion time. To overcome this problem defined coating systems were checked. It could be shown that especially Zinc-coatings (electrogalvanising and hot-dip galvanizing) are able to create a metallic continuity between steel and casting component. Nevertheless a complete metallic continuity was not received. Furthermore mechanical tests were conducted to analyze the failure mechanism of hybrid structures with and without metallic continuity. It could be shown that at early deformation trajectories hybrid structures without metallic continuity take up more energy than hybrid structure with metallic continuity. The behavior changes with increasing deformation trajectories.
KW  - Verbundwerkstoff (SWD)
KW  - Druckguss (SWD)
KW  - Aluminiumguss (SWD)
KW  - Karosserie (SWD)
LB  - PUB:(DE-HGF)11 ; PUB:(DE-HGF)3
UR  - https://publications.rwth-aachen.de/record/211917
ER  -