Dresden 2020 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 40: Topical Session: Interface-dominated phenomena - Solutes at Interfaces I
MM 40.4: Talk
Wednesday, March 18, 2020, 16:45–17:00, IFW A
The effect of grain boundary segregation on embrittlement: recent trends and open questions — Pavel Lejček1 and •Mojmir Šob2,3,4 — 1Inst. Phys., Acad. Sci. Czech Rep., Prague — 2Masaryk Univ., Fac. Sci., Dept. of Chem., Brno, Czech Rep. — 3Inst. Phys. Mat., Acad. Sci. Czech Rep., Brno — 4Central Europ. Inst. Technol., CEITEC MU, Masaryk Univ., Brno
To elucidate the effect of individual solutes on embrittlement of various base materials such as steels and nickel-base superalloys, grain boundary and surface segregation was extensively studied in many laboratories. Unfortunately, the values of the segregation energy of a solute at grain boundaries as well as at the surfaces obtained by various authors sometimes differ by more than one order of magnitude: such a difference is unacceptable as it cannot provide us with representative view on the problem of material temper embrittlement Here we summarize the available data on interfacial segregation and embrittlement of various solutes in nickel and bcc iron and critically discuss their reliability, assessing also limitations of individual approaches employed to determine the values of segregation and strengthening/embrittling energies. We demonstrate that theoretical approaches are limited by the size of the computational repeat cell used for the calculations of the segregation energy. On the other hand, the change in the grain boundary cohesion (strengthening/embrittling energy) may be obtained with a reasonable accuracy. For many impurities, there is lack of experimental segregation data. Therefore, many calculated results are theoretical predictions which may motivate future experimental work.