A doctoral defence in the times of Corona
Despite the restrictions on everyday university life associated with the COVID-19 pandemic, the WOT succeeded in defending its doctorate in accordance with the rules. On 8 July 2020, Lisa Winter convinced the reviewers present as well as the digitally connected colleagues, friends and family members with her thesis on „Fatigue strength and medium-voltage sensitivity of the alloy AlMgSi1 after highly plastic deformation and anodic or plasma-electrolytic oxidation“.
After passing the non-public revision course, Ms Winter used the Big Blue Button conference system at Chemnitz University of Technology to talk about the possibility of using conversion treatment to increase the reduced fatigue strength of highly plastically deformed aluminium materials. In order to develop this combination for technically relevant applications, in-depth research into the mutual relationships between the substrate material, the conversion layer and the resulting range of properties of the substrates under cyclic loading was necessary. The influence of the type of conversion layer on the fatigue strength and cracking behaviour had not yet been sufficiently investigated, particularly in combination with a highly plastically formed substrate. In her work, Ms Winter investigated the frequently used wrought aluminium alloy EN AW-6082 (AlMgSi1). The highly plastic forming was achieved using the Equal Channel Angular Pressing (ECAP) process available at the IWW. The fatigue strengths in the so-called HCF range (High Cycle Fatigue) of anodic, hard anodic and plasma-electrolytic conversion treatments of surfaces of different ECAP-treated and undeformed states of the selected substrate material were then compared. The present work thus makes an important contribution to understanding the complex relationships between the structure of the conversion layer, the microstructure and properties of the substrate material and the resulting fatigue strength as a function of the applied mean stress.
The work was published in the IWW's own publication series „Werkstoffe und werkstofftechnische Anwendungen“ (Volume 87, ISBN 978-3-949005-01-5).
Picture:
Prof Lutz Krüger (second reviewer), Dr Lisa Winter, Prof Thomas Lampke (doctoral supervisor and first reviewer) and Prof Guntram Wagner (head of the doctoral procedure)
30.7.2020 – Personnel of the professorship ( thomas.grund@mb… )
