An Analytical Modeling for Bridging Stress Function Involving Grain Size Distribution in a Polycrystalline Alumina

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J. Korean Ceram. Soc. > Volume 31(12); 1994 > Article

Journal of the Korean Ceramic Society 1994;31(12): 1449.

다결정 알루미나에서 결정립 크기 분포를 포함하는 Bridging 응력함수의 해석적 모델링

손기선, 이성학, 백성기

포항공과대학교 재료금속공학과

An Analytical Modeling for Bridging Stress Function Involving Grain Size Distribution in a Polycrystalline Alumina

ABSTRACT

A new analytical model which can discribe the relationship between the bridging stress and the crack opening displacement was proposed to investigate the microstructural effect on the R-curve behavior in a polycrystalline alumina. The crack opening displacement according to the distance behind the stationary crack tip was measured using in-situ fracture technique in an SEM, and then used for a fitting procedure to obtain the distribution of bridging stress. The current model and an empirical power law relation were introduced into the fitting procedure. The results indicated that the bridging stress function and R-curve computed by the current model were consistent with those computed by the power law relation. The microstructural factor, e.g., the distribution of grain size, was also found to be closely related to the bridging stress. Thus, this model explained well the interaction effect between the distribution of bridging stress and the local-fracture-controlling microstructure, providing important information for the systematic interpretation of microfracture mechanism including R-curve behavior of a monolithic alumina.