Fundamental Studies on the Mechanical Behavior and Fracture Characteristics ofMetal-Ceramic Interfaces

摘要

Composite properties are closely related to the strength of the interface betweenthe matrix and reinforcement. There is need for a fundamental level of understanding of the strength characteristics and the origin of failure of the interface since it is the means by which load is transferred from the matrix to reinforcement. Extended from our previous phase of this study of the interface between ductile and brittle phases under mode II loading, 4 an offset shear geometry was chosen to investigate the strength and fracture behavior of a copper/alumina sandwich. This particular geometry has advantages since it is simple to fabricate and can provide mixed mode information about strength. In this phase of the study, an attempt has been made to characterize the shear debond strength of metal-ceramic interface by use of the offset shear specimen. Specimens with interface precrack geometries as well as those without precracks were tested to examine crack propagation and initiation effects. The goal is to characterize mechanisms of damage initiation at the interface prior to crack propagation using copper-alumina laminates loaded in compression. During each test, crack initiation information was obtained from critical stress to initiate fracture, and propagation information was determined from the energy requirement for subsequent crack propagation.