Vickers and Knoop Indentation Microhardness Study of ?-SiAION Ceramic

Abstract

In this paper, analysis and interpretation of mechanical property measurements of beta-SiAION ceramic were reported. Indentation microhardness of beta-SiAION ceramic was measured using the Knoop and Vickers indenters. The analysis of the Vickers indentation microhardness data reveals the reverse indentation size effect that is the apparent microhardness increases with increasing applied indentation test load. However, the Knoop indentation microhardness data exhibit indentation size effect that is the apparent microhardness increases with decreasing applied test load. The experimental Knoop microhardness data was analyzed using Meyer's law, elastic-plastic deformation model, proportional specimen resistance model, and Hays-Kendall's model. As a result, modified proportional specimen resistance model is found to be the most effective one for the load-independent (Hu) microhardness determination of the SiAION ceramic. It was seen that different models used to analyze the data obtained from the Vickers indentation do not give the same intrinsic hardness value. We also present the calculation of the Young modulus, E, of the beta-SiAION ceramic.