FEMS
Oliver Marian Preuß
Oliver studied Materials Science at the Technical University of Darmstadt, Germany. After investigating the mechanical properties of diamond coatings during his Bachelor's thesis, he did his Master's thesis in the field of dislocations in ceramics in 2021, under the supervision of Dr Xufei Fang. Continuing this topic, he started a PhD on dislocation-based toughening in ceramics co-supervised by Prof Dr Jürgen Rödel and Dr Xufei Fang.
Oliver attended 3 international (incl. USA and Japan) and 5 national conferences and was the winner of the 2024 FEMS Master Thesis Award. His first paper achieved 'Editor’s Choice' by the American Ceramic Society and he also won three prizes in the ceramographic competition of the American Ceramic Society, including the Roland B Snow award for best-of-show. In his free-time, he practices luthiery and builds his own guitars.
Dislocation-Based Toughening and Damage-Tolerance in Oxide Ceramics
The growing research interest in dislocation tuned functionality in ceramics is evident, with the most recent proofs of concept for enhanced ferroelectric properties, electrical conductivity, and superconductivity via dislocations. In this study, we focus on dislocation-tuned mechanical properties and demonstrate that, by engineering high dislocation densities (up to 1014 per m2) into KNbO3 at room temperature, the fracture toughness can be increased by a factor of 2.8 compared to the reference.
A strong interaction between the dislocations and the ferroelectric domains was found, whose effect on the toughness is ruled out by a high-temperature indentation experiment. By an improved deformation technique, the dislocation density in MgO can reach over 1015 per m2, which leads to full crack suppression.