Segregation induced embrittlement of grain interfaces

Publisher Website
Google Scholar
Abstract
Conditions are discussed under which an interface, possibly containing an adsorbed species, is capable of sustaining an atomistically sharp cleavage crack, rather than having any such crack blunt out via dislocation nucleation. Two models for ductile versus brittle interface response are discussed. One of these is applied to model grain boundaries in face centered cubic materials, and is used to compare predictions with experimental observations on the embrittlement of Cu polycrystals by the addition of dilute concentrations of Bi. The general results are in qualitative agreement, although the model predicts behavior that is, in general, more ductile than that observed experimentally. Several possible reasons for this excess ductility are discussed. An appendix presents an analysis of the work of reversible separation of an interface containing a segregated species. This is intended to clarify some issues recently raised in the literature on interfacial embrittlement, especially concerning the distinctions that must be drawn between expressions for cohesive energy reductions for interfacial separation at constant chemical potential, ..mu.., versus separation with constant concentration, GAMMA, of the adsorbate species.

This publication has 0 references indexed in Scilit: