Technical staff member, Sandia Laboratories, Albuquerque, N. Mex.
Ceramic engineer, National Bureau of Standards, Washington, D. C.
Pages: 15 Published: Jan 1979
Fracture surface analysis of brittle materials can be used as a quantitative tool to determine not only the size of the fracture initiating flaw but also the stress at failure and the critical fracture toughness of the material. The techniques for standardizing these fracture surface measurements and the influence of factors such as microstructure, internal stress, and loading rate are described. The sizes and geometries of fracture initiating flaws are correlated with the KIc of the material local to the flaw periphery and these are compared to the KIc obtained from fracture surface analysis. Failure under combined KI and KII loading is shown to become more amenable to analysis through the use of fractography. Static fatigue failures can be analyzed through the fracture surface features they generate. Not only the stress causing failure but also the time under stress can be determined quantitatively through measurement of flaw and “fracture mirror” sizes.
fracture (materials), fractography, ceramics, fracture mechanics, brittle materials, mechanical properties
Paper ID: STP36632S