IROAST Visiting Professor Pavel Lejček from the Institute of Physics at the Czech Academy of Sciences gave a special lecture for students on October 17, 2017. After an introduction by Professor Tsurekawa, Professor Lejček gave a talk entitled "Solute segregation at grain boundaries and their embrittlement; Czech footprint" in a classroom filled with about 70 students.
IROAST will invite our Visiting Professor Pavel Lejček from the Institute of Physics at the Czech Academy of Sciences to give the following 13th IROAST Seminar. We hope to see many of you there.
Time & Date: 10:20 - 11:50, Tuesday, Oct. 17, 2017
Venue: #308, Faculty of Engineering Research Building I, Kumamto University
Lecturer: Prof. Pavel Lejček, Institute of Physics, AS CR Praha, Czech Republic
Title: Solute segregation at grain boundaries 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 lecture we summarize the fundamentals of the grain boundary segregation and changes of the cohesion caused by this phenomenon and document them for examples of our effort. Individual points to be presented and discussed are (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 discuss (6) Comparison of calculated data and experimental results on grain boundary segregation and embrittlement and discuss the differences between them.
Contact: Professor Tsurekawa, Faculty of Advanced Science and Technology
Email: turekawa@* (Please change “*” to “kumamoto-u.ac.jp”.)