Effect of metallic binder content on the microhardness of TiCN-based cermets

Microhardness testing was conducted on a series of TiCN-based cermets with different contents of metallic binders in the applied load range from 0.49 to 9.8 N. Significant indentation size effect (ISE) in the measured microhardness was observed for each test sample. The traditional Meyerʹs law and the modified proportional specimen resistance (MPSR) model were employed to analyze the load-dependence of the measured hardness. It was found that the Meyerʹs exponent n increases with the metallic binder content, implying that increasing the metallic binder content would restrain the ISE. The load-independent hardness was found to decrease with the increasing metallic binder content. This can be attributed to the fact that the hardness of metallic binder is lower than that of the TiCN matrix.