• Theissing, Moritz
• Falkinger, Georg
• Mitsche, Stefan

Abstract

During the production of wrought aluminum alloys, depending on the material<br/>recrystallization may occur at several stages in the process chain, affecting the final<br/>microstructure. Since microstructure is directly related to material properties, an<br/>understanding of recrystallization is of great importance. Investigations are challenging due<br/>to the rapid transformation and multiple mechanisms interacting at the microscale. Adequate<br/>characterization is not easy and the method used must be carefully selected depending on<br/>the research question. In this work, different methods such as hardness measurements,<br/>optical microscopy, in situ electron backscatter diffraction (EBSD) and ex situ EBSD have<br/>been tested and their applicability to the problem has been evaluated. Each method has its<br/>advantages and disadvantages, and there are limitations that are not obvious at first glance.<br/>An industrial AA8079 foil stock alloy was used to test the methods. The recrystallization<br/>kinetics were determined using the different methods and the results are compared and<br/>discussed. In addition, the initial phase of recrystallization was studied in more detail using in<br/>situ EBSD. The interaction between subgrain growth and nucleation of new grains was<br/>recorded and the results are discussed. Recrystallization and concurrent precipitation were<br/>studied in an industrial AA6016 alloy for automotive applications. Precipitation was found to<br/>have a strong influence on the recrystallization kinetics depending on the heating rate.

Topics

• impedance spectroscopy
• grain
• phase
• aluminium
• hardness
• precipitation
• electron backscatter diffraction
• optical microscopy
• recrystallization