Fracture toughness of wet and dry particulate materials comprised of colloidal sized particles: Role of plastic deformation

Abstract

This work demonstrates a method of measuring the fracture toughness of particulate materials comprised of colloidal sized particles over a wide range of saturation. Diametral compression of cylinders containing flaws of controlled length was used to measure the mode I fracture toughness. The effect of degree of saturation on the fracture toughness of slip cast ceramic grade alumina (d50 = 0.7 μm) was investigated. Dry powder compacts have significantly lower fracture toughness than when the powder compact is nearly fully saturated. All observations are consistent with the fracture mechanism being predominantly brittle for the dry samples but predominantly ductile in the nearly saturated samp..