Print Email Facebook Twitter Microchemistry in aluminium sheet production Title Microchemistry in aluminium sheet production Author Lok, Z.J. Contributor Van der Zwaag, S. (promotor) Faculty Aerospace Engineering Date 2005-04-26 Abstract The production of aluminium sheet alloys from as-cast ingots is a complex process, involving several rolling operations in combination with various thermal heat treatments. Through their influence on the alloy microchemistry and microstructure, these thermomechanical treatments are all aimed at controlling the final material properties. In addition, microchemistry and microstructure also affect each others development, which makes their control during industrial processing a rather complex issue. For this reason an EU-supported project under the name VIR[*], was started in March 2000, in which several European aluminium producers and research institutes co-operated in developing physically based models for the microchemistry and microstructure evolution during industrial processing of non heat-treatable aluminium alloys. The present PhD-research is part of the VIR[*] results and focusses at the influence of microstructure on the Mn precipitation in a commercial Al-Mn-Fe-Si alloy (AA3103). Firstly, several techniques for measuring the concentration of aluminium alloying elements in solid solution, are evaluated. Measurement of the thermoelectric power (TEP) proves to be the most reliable technique. As opposed to electrical resistivity and microprobe analysis, its signal is hardly influenced by alloy features other than solute atoms (e.g. precipitates). It is also shown that by combining TEP and resistivity, it is possible to independently measure the Fe and Si solute levels in a commercial Al-Fe-Si alloy. Subsequently, commercial AA3103 was solutionised, hot rolled and annealed under laboratory conditions. TEP measurements show that the precipitation of solute Mn slows down significantly as the material recrystallises. It is assumed that a large difference in Mn diffusivity between the deformed and undeformed microstructure is responsible for this effect. This observation serves as basis for a quantitative precipitation model that is also able to include the effects of an evolving microstructure. Finally, the predictive power of the precipitation model is tested. After coupling with a VIR[*] microstructure model, the microchemistry predictions are compared with measurments on AA3103 samples taken from various stages of the industrial processing route. It shows that, although not always quantitatively accurate, the measured microchemical trends are well reproduced. Subject aluminium alloyssolutesprecipitationdeformationmodelling To reference this document use: http://resolver.tudelft.nl/uuid:38aa1c82-f543-42e9-b55c-f0a1b51c0214 ISBN 90-771-7215-7 Part of collection Institutional Repository Document type doctoral thesis Rights (c) 2005 Z.J. Lok Files PDF ae_lok_20050426.pdf 10.23 MB Close viewer /islandora/object/uuid:38aa1c82-f543-42e9-b55c-f0a1b51c0214/datastream/OBJ/view