Extraction of flow properties of single crystal silicon carbide by nanoindentation in combination with finite element simulation

초록

A method is presented for estimating the plastic flow behavior of brittle ceramic materials like silicon carbide by combining nanoindentation experiments conducted with a series of triangular pyramidal indenters having different indenter angles (35.3° to 75° in this work) in combination with finite element simulations. The method is based on Tabor`s concepts of characteristic strain, char and constraint factor, C , which enable indentation hardnesses with the different indenters to be related to the flow properties of the material. The procedure relies on 2D axisymmetric finite element 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. It is shown how the uniaxial stress-strain curve of brittle/hard materials may conceivably be estimated from the procedures, and that friction between the indenter and the material plays a significant role.