Dissolution and Precipitation Behavior for Hot Forming of 7021 and 7075 Aluminum Alloys
Benjamin Milkereit,
Martin Österreich,
Philipp Schuster,
Georg Kirov,
Ermal Mukeli,
Olaf Kessler
Affiliations
Benjamin Milkereit
Chair of Materials Science, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Albert-Einstein-Str. 2, 18059 Rostock, Germany
Martin Österreich
Chair of Materials Science, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Albert-Einstein-Str. 2, 18059 Rostock, Germany
Philipp Schuster
Light Metals Technologies Ranshofen, Austrian Institute of Technology, Lamprechtshausener Str. 61, P.O. Box 26, 5282 Ranshofen, Austria
Georg Kirov
Light Metals Technologies Ranshofen, Austrian Institute of Technology, Lamprechtshausener Str. 61, P.O. Box 26, 5282 Ranshofen, Austria
Ermal Mukeli
Magna Steyr AG & Co KG, Liebenauer Hauptstraße 317, 8041 Graz, Austria
Olaf Kessler
Chair of Materials Science, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Albert-Einstein-Str. 2, 18059 Rostock, Germany
Due to their high strength, 7xxx aluminum sheets are increasingly used for structural automobile components. One of the major challenges is the formability of these alloys during the production process while retaining high strengths in service. One promising method is forming at elevated temperatures directly after solution annealing; this is known as hot forming. However, this thermomechanical process requires a detailed comprehension of the dissolution and precipitation behavior during heating, solution annealing, and subsequent combination of forming and cooling processes. Therefore, the kinetics of solid-solid phase transformations during continuous heating and continuous cooling of the aluminum alloys EN AW-7021 and EN AW-7075 were determined with differential scanning calorimetry and hardness testing. The suitable solution annealing conditions and the critical cooling rates were specified for both alloys and compared to the real hot forming processes.
