Abstract
In order to improve the brittleness of ceramic materials, alumina/30vol% stainless steel (SUS316L) composites were prepared and their mechanical properties were studied from the viewpoint of particle size of dispersed stainless steel. The toughening mechanism of the composite was estimated using COD (Crack Opening Displacement) technique. Increase in the particle size was effective in promoting the interaction between fractured surfaces and enhanced the stress shielding of the crack tip, resulting in improvement of the fracture toughness. For the composite prepared from stainless steel with an average particle size of 20μm, the fracture toughness remarkably increased to 9.5MPa·m1/2, compared with 2.4MPa·m1/2 for monolithic alumina. Blocking of crack propagation and crack deflection were observed around stainless steel particles, as increasing the particle size.
