Study of the mechanical properties, toughening and strengthening mechanisms of Si3N4/Si3N4w/TiN nanocomposite ceramic tool materials

Abstract Si 3 N 4 /Si 3 N 4w /TiN nanocomposites were fabricated by a hot-pressing technology with different sintering processes. The effect of nanoscale TiN and Si 3 N 4w on the mechanical properties was investigated. The microstructure and indention cracks were observed by scanning electron microscopy, transmission electron microscopy and energy-dispersive spectrometry investigations. The research results showed that Si 3 N 4 /Si 3 N 4w 20/TiN5 nanocomposites containing 5 vol.% of nanoscale TiN and 20 vol.% of nanoscale Si 3 N 4w , which were sintered under a pressure of 30 MPa at a temperature of 1650 °C for 40 min, had optimum mechanical properties. The addition of both nanoscale TiN and nanoscale Si 3 N 4w contributed to the microstructural evolution and an improvement of the mechanical properties. The toughening and strengthening mechanisms are discussed for Si 3 N 4 /Si 3 N 4w 20/TiN5 nanocomposites.