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On the relation between creep cavitation and grain boundary orientation. [Cu-Sb]

Journal Article · · Scr. Metall.; (United States)

The purpose of this paper is to study the influence of grain boundary inclination angle on the creep cavitation process. The cavitation rate on a grain boundary facet is expected to depend on its inclination angle, because differently oriented facets have different stress states. Although qualitative observations have been reported occasionally, this problem has not been studied extensively. The process of creep cavitation can be divided into two parts: cavity nucleation and cavity growth. From a theoretical point of view, these processes depend on grain boundary inclination in different ways. It is generally believed that grain boundary sliding is necessary to provide the stress concentrations needed for the nucleation of cavities. The cavity nucleation rate is therefore expected to peak on inclined boundaries, where grain boundary sliding is at a maximum. On the other hand, transverse grain boundaries are more favorable for cavity growth. The higher normal tractions acting on these boundaries provide a steeper chemical potential gradient for diffusive cavity growth. The influence of grain boundary inclination on the creep cavity nucleation and growth rate has been studied using SEM and a stereo microscopy technique in a Cu-Sb alloy. Both were higher on transverse boundaries. A possible explanation for the higher nucleation rate on transverse boundaries by stochastic grain boundary sliding has been proposed.

Research Organization:
Department of Materials Science and Engineering, Stanford University, Stanford, California
OSTI ID:
6469423
Journal Information:
Scr. Metall.; (United States), Journal Name: Scr. Metall.; (United States) Vol. 18:2; ISSN SCRMB
Country of Publication:
United States
Language:
English