Microstructure-Strength Properties in Ceramics: I, Effect of Crack Size on Toughness

A systematic study of the inert‐strength characteristics of ceramics as a function of crack size relative to grain size has been made using controlled indentation flaws. The focus of the test program is on aluminas, with barium titanates and glass‐ceramics providing support data in confirmation of general trends. On progressively diminishing the indentation load, the strengths first show a steady increase, but subsequently tend to a plateau, as...