Static and cyclic fatigue failure at high temperature in ceramics containing grain boundary phase: experiments

K. J. Hsia, N. Dey, D. F. Socie

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Fatigue behavior of a commercial grade alumina with 6 wt% of grain boundary viscous phase was investigated. Uniaxial tensile tests were conducted under both static and cyclic loading at 1000 C. The fatigue lifetime was measured as a function of the maximum applied stress. The failure mechanisms were studied using scanning electron microscopy. Under static loading, two different failure mechanisms were observed: at high applied stresses, fracture was dictated by the slow growth of a single dominant flaw along the grain boundaries; at low applied stresses, fracture occurred due to the nucleation, growth and linkage of multiple macrocracks. Under cyclic loading within the stress range in the present investigation, fracture was dominated by the slow growth of a single crack. In the slow crack growth regime where crack growth is driven by Irwin's stress intensity factor, the lifetime under cyclic loading was longer than that under static loading (for the same maximum stress) by approximately a factor of 30. Extensive crack surface bridging by viscous grain boundary phase behind the crack tip was observed. The viscous bridging was believed to be the most important factor for the observed cyclic strengthening behavior.

Original languageEnglish (US)
Title of host publicationCleavage Fracture
EditorsK.S. Chan
PublisherMinerals, Metals & Materials Soc (TMS)
Pages367-376
Number of pages10
StatePublished - 1997
EventProceedings of the 1997 TMS Fall Meeting - Indianapolis, IN, USA
Duration: Sep 15 1997Sep 17 1997

Other

OtherProceedings of the 1997 TMS Fall Meeting
CityIndianapolis, IN, USA
Period9/15/979/17/97

ASJC Scopus subject areas

  • General Engineering

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