Mechanisms and Mechanics Governing the Indentation of Polycrystalline Alumina

Abstract

A constitutive model for the inelastic deformation of polycrystalline alumina that accounts for both microcrack growth and plastic slip is implemented into a commercial finite element code. To establish its applicability, the code is used to simulate the deformation that occurs upon spherical and conical indentation. Inelastic zones and indentation pressures are predicted over a range of grain size and compared with measurements. The model replicates the mechanism transition from plasticity control at small grain sizes to micro‐crack‐control at large grain sizes. It also predicts an extensive micro‐crack‐dominated inelastic zone at large grain size that reduces the indentation pressures.