Accession Number : AD0787743

Title :   High Temperature Slow Crack Growth in Ceramic Materials.

Descriptive Note : Interim rept. 1 Sep 73-31 Jan 74,

Corporate Author : NATIONAL BUREAU OF STANDARDS WASHINGTON D C INST FOR MATERIALS RESEARCH

Personal Author(s) : Evans,A. G.

Report Date : FEB 1974

Pagination or Media Count : 49

Abstract : High temperature slow crack growth processes in several ceramic materials are examined under static and cyclic loading conditions. Data obtained at temperatures up to 1400C are used for purposes of failure prediction and for analysis of the slow crack growth phenomena. It is shown that purity plays a major role in slow crack growth resistance, particularly in the hot pressed materials, and that cycling in the low frequency regime does not significantly increase the rate of slow crack growth. The slow crack growth mechanisms appear to be primarily plasticity related. Two semi-quantitative mechanisms are presented, one due to dislocation motion and the other due to grain boundary sliding. (Author)

Descriptors :   *Ceramic materials, *Fracture(Mechanics), Crack propagation, Loads(Forces), Cycles, Static loads, Fatigue(Mechanics), Failure, High temperature, Forecasting

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE