Extraction of flow properties of single-crystal silicon carbide by nanoindentation and finite-element simulation

Abstract

A method is presented for estimating the plastic flow behavior of single-crystal silicon carbide by nanoindentation experiments using a series of triangular pyramidal indenters with five different centerline-to-face angles in combination with two-dimensional axisymmetric finite-element (FE) simulations. The method is based on Tabor's concepts of characteristic strain and constraint factor. which allow indentation hardness values obtained with indenters of different angles to be related to the flow properties of the indented material. The procedure utilizes FE simulations applied in an iterative manner in order to establish the yield strength and work-hardening exponent from the experimentally measured dependence of the hardness on indenter angle. The methodology is applied to a hard, brittle ceramic material. 6H-SiC, whose flow behavior cannot be determined by conventional tension or compression testing. It is shown that the friction between the indenter and the material plays a significant role. especially for very sharp indenters.