Seminar of the Research Group Materials with Controlled Microstructure

will be held on

Friday, May 12, 2017, at 9:30 in the lecture hall of the Institute.

Program:

Pavel Lejček (M. Šob, V. Paidar): Solute segregation at interfaces and their embrittlement: Czech footprint

Abstract:

One of the most dangerous technical failures of materials is intergranular brittle fracture (temper embrittlement) as it proceeds very quickly and its appearance is often hardly predictable. It is known that this phenomenon is closely related to the chemistry (solute segregation) of grain boundaries and free surfaces. To elucidate the effect of individual solutes on embrittlement of various materials such as steels and nickel-base superalloys, grain boundary and surface segregations were extensively studied in many laboratories throughout the world: an indisputable contribution to this database was also provided by the groups from the Czech Republic (Prague and Brno). In this talk we summarize our effort concerning (1) Anisotropy of grain boundary segregation and classification of high angle grain boundaries; (2) Grain boundary segregation diagram; (3) Enthalpy/entropy compensation effect; (4) Prediction of grain boundary segregation; and (5) Segregation volume. Finally, we will also compare calculated data and experimental results on grain boundary segregation and embrittlement and discuss the differences between them.