A step towards normality: first live PhD Defense at the RWTH Aachen University
After about four months of online examination to condemn the Corona pandemic in Germany, Dr. Yu Qin was the first researcher of the MPIE who successfully defended her PhD live at the RWTH Aachen University on 2nd July.
Qin did her PhD in the group “Material Science of Mechanical Contacts” headed by Dr. Michael Herbig. Her thesis discusses microstructure alterations in bearing steels exposed to severe plastic deformation. Qin’s research aims at finding counter measures against white etching cracks (WECs) that lead to unpredictable premature bearing failures. To understand the microstructure alterations in bearing steels induced by severe plastic deformation, and to investigate the microstructure characteristics of bearing steels that resist to this failure mechanism, she used scanning and transmission electron microscopy, as well as atom probe tomography and nano-indentation. Qin proposes in her thesis potential methods for the mitigation of WECs in bearing applications and gives insights into the design of new bearing steels with high WEC resistance. The results pave the way for the development of more durable wind turbine bearings, which till now suffer from the phenomenon of WECs.