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@article{1381985, author = {Lejcek, Pavel and Šob, Mojmír and Paidar, Vaclav}, article_location = {OXFORD}, article_number = {June}, doi = {http://dx.doi.org/10.1016/j.pmatsci.2016.11.001}, keywords = {Solute segregation; Interfacial embrittlement; Grain boundary; Free surface; Computer modeling; Measurements of local composition}, language = {eng}, issn = {0079-6425}, journal = {Progress in Materials Science}, title = {Interfacial segregation and grain boundary embrittlement: An overview and critical assessment of experimental data and calculated results}, url = {http://www.sciencedirect.com/science/article/pii/S0079642516300755}, volume = {87}, year = {2017} }
TY - JOUR ID - 1381985 AU - Lejcek, Pavel - Šob, Mojmír - Paidar, Vaclav PY - 2017 TI - Interfacial segregation and grain boundary embrittlement: An overview and critical assessment of experimental data and calculated results JF - Progress in Materials Science VL - 87 IS - June SP - 83-139 EP - 83-139 PB - PERGAMON-ELSEVIER SCIENCE LTD SN - 00796425 KW - Solute segregation KW - Interfacial embrittlement KW - Grain boundary KW - Free surface KW - Computer modeling KW - Measurements of local composition UR - http://www.sciencedirect.com/science/article/pii/S0079642516300755 L2 - http://www.sciencedirect.com/science/article/pii/S0079642516300755 N2 - 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 of grain boundaries and to the difference of the segregation energies of the grain boundaries and the free surfaces (RiceWang model). To elucidate the effect of individual solutes on embrittlement of various materials such as steels and nickel-base superalloys, grain boundary and surface segregation was extensively studied in many laboratories. As a result, numerous data on surface and grain boundary segregation have been gathered in literature. They were obtained in two main ways, by computer simulations and from experiments. Consequently, these results are frequently applied to quantify the embrittling potency of individual solutes. 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. In some cases it seems that these values do not properly reflect physical reality or are incorrectly interpreted. Due to the above mentioned large scatter of the segregation and embrittlement data a critical assessment of the literature results is highly needed which would enable the reader to avoid both the well known and less well known pitfalls in this field. 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, such as density functional theory, Monte Carlo method, molecular statics and dynamics and tight binding on the theoretical side, and Auger electron spectroscopy, 3D tomographic atom probe, and electron microscopy techniques on the experimental side. We show that experimental methods have serious limitations which can be overcome by accepting reasonable assumptions and models. On the other hand, the theoretical approaches are limited by the size of the computational repeat cell used for the calculations of the segregation energy. In both cases, a careful critical analysis of the available segregation energy and/or enthalpy reflecting physical reality allows to assess the reliability of these values and their applicability in analysis of intergranular brittle fracture in steels and nickel-base alloys. (C) 2016 Elsevier Ltd. All rights reserved. ER -
LEJCEK, Pavel, Mojmír ŠOB a Vaclav PAIDAR. Interfacial segregation and grain boundary embrittlement: An overview and critical assessment of experimental data and calculated results. \textit{Progress in Materials Science}. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD, 2017, roč.~87, June, s.~83-139. ISSN~0079-6425. Dostupné z: https://dx.doi.org/10.1016/j.pmatsci.2016.11.001.
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