Improvement of sialon based composite materials for machining of nickel based superalloys

SiCp reinforcement was applied to a SiAlON-based cutting toolcomposition , which is the subgroup of ceramic cutting tools used for machiningsuperalloys, in order to improve resistance against to abrasive cutting conditions.10, 17.5, and 25 weight % of SiC amounts were added to a SiAlON compositioncontaining 50 %α- 50 %β phases, and sintering behaviour, mechanical properties(hardness and toughness) thermal properties and wear behaviour duringmachining of Inonel 718, a nickel-based superalloy used widelly. SiC particleshaving the specific surface area 25m2/g. was used to determine the effect of theparticle size of the SiCp. According to sintering results 17,5 % SiC addition is thelimit for obtaining complete densification in SiCp-SiAlON composite material inthis system. Without a considerable effect of the particle size of the SiCp, increasein SiCp content results to an increase in hardness and thermal diffüsivity but not aconsiderable alteration in fracture toughness. In terms of mechanical and thermalproperties, the superior material, that contains 17.5% SiC, has higher wearresistance than SiAlON material, and comparable wear resistance withcommercial SiCv-Alümina cutting tools.Keywords: Superalloys, Machining, Ceramic cutting tools, SiCp-SiAlONcomposite materials, Microstructure.ii