Evaluation of fracture toughness for metal/Ceramics composite materials by means of miniaturized specimen technique.

Abstract

In order to evaluate fracture strength for Y2O3-ZrO2, 3mol% Y2O3-ZrO2 (PSZ) /SUS 304 composite materials, Macor as a machinable ceramics and comercially available ceramics (SiC, Si3N4, PSZ, Al2O3), fracture toughness tests were carried out by use of RCT or bending specimens. On the other hand, the fracture strength of these materials was evaluated and inspected the correlation between fracture toughness and fracture stress of small punch (SP) or modified small punch (MSP)test data to predict the fracture toughness value by using miniaturized specimens. Characteristic of the MSP testing method is the ability to evaluate elastic modulus (Young's modulus), fracture strength, yield strength, fracture strain, and fracture energy, etc., with high accuracy and good reproducibility for brittle materials. For a series of metal/ceramics composites which from ductile to brittle, this paper clarified clear the applicable range for SP and MSP testing methods, which suggested that the simultaneous use of SP and MSP test methods can evaluate the fracture strength of metal/ceramics composites.