CUTTING PERFORMANCE AND WEAR MECHANISM OF Si3N4-BASED NANOCOMPOSITE CERAMIC CUTTING TOOL IN MACHINING OF CAST IRON

Abstract

A type of Si3N4-based nanocomposites ceramic cutting tool material was prepared by the addition of nano-scale Si3N4W whisker and nano-scale TiN particle. Cutting performance of the Si3N4/Si3N4W/TiN nanocomposite ceramic tool in machining of cast iron was investigated in comparison with a commercial sialon ceramic tool, and the tool wear mechanism was studied. The two types of cutting tools have similar cutting performance at relatively low cutting parameters, while Si3N4/Si3N4W/TiN nanocomposite tool exhibits a better wear resistance than sialon tool at the relatively high cutting parameters. The wear of sialon ceramic cutting tool is dominated by the plastic deformation, abrasive action, microcracking, pullout of grains and chemical action at the higher cutting parameters. The higher mechanical properties, and the refined matrix grains, intragranular TiN grains and dislocation in the microstructure improve the resistances to plastic deformation, microcracking, and pullout of grains for Si3N4/Si3N4W/TiN nanocomposite ceramic cutting tool. The wear of Si3N4/Si3N4W/TiN nanocomposite ceramic cutting tool is dominated by the abrasive and chemical actions at the higher cutting parameters.