ニッケル粒子分散アルミナ系複合材料の作製と力学的特性(<特集>セラミック材料)

概要

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Fracture toughness and other mechnical properties of alumina matrix composite reinforced with nickel particles were measured. Nickel/alumina composites up to 25 vol% of nickel contents were prepared by sintering in fine graphite powder bed under N_2 gas atmosphere. Vibration was also applied during sintering to promote the dispersion of nickel particles in alumina matrix, using a high-frequency apparatus. Decrease in Young's modulus and three-point bending strength was observed with increasing nickel content. The fracture toughness, on the other hand, measured by SEVNB method increased with increasing nickel content. The fracture energy of composite was estimated by Griffith equation according to the observed fracture touhtness and Young's modulus. The fracture energy increased in proportion to the total surface area of nickel particles comprized in the unit volume of composite. Increase in fracture energy corresponded to the formation of microcracks, which generated on nickel particles in the frontal process zone of composite. Decrease in bending strength was explained by the formation of large defects in composite, due to the large pore, decreasing of interparticle spacing or aggregation of nickel particles.
社団法人日本材料学会の論文
1998-06-15