Role of Microstructure in Hertzian Contact Damage in Silicon Nitride: I, Mechanical Characterization

In this Part I of a two‐part study of Hertzian indentation in silicon nitride we characterize irreversible contact damage as a function of microstructure. Three controlled silicon nitride microstructures are examined, representing a progression toward greater long‐crack toughness: fine (F), bimodal with predominantly equiaxed α grains; medium (M), bimodal with mostly β grains of intermediate size; and coarse (C), with almost exclusively...