LOCAL INTERFACE RESPONSE TO DISLOCATION STRAIN FIELDS AT THE AL SIO2 AND AL/C BOUNDARY REGION/

This work presents a transmission electron microscopy study of the loc al bimaterial interface response to applied stress. The intersection o f a dislocation moving at some angle to the incoherent bimaterial inte rface with the interface results in the creation of a dislocation line defect (an extrinsic defect) at the interface. The intersection of th e strain field of these defects with the interface is analogous to per forming a tensile test or a shear test on the interface, but on the at omic scale. This paper will examine how the mechanical stability of th is type of extrinsic defect can be a measure of the strength of the in terface. A measure of this stability can be performed by examining the degree of interfacial defect relaxation, as determined by the diffrac tion contrast in the transmission electron microscope under an applied stress. We compare in this work the interface between sputter-cleaned Al and sputter-deposited, amorphous SiO2 and the interface between sp utter-cleaned Al and sputter-deposited, amorphous C. It is found that the amorphous carbon/aluminum interface region is much weaker than the amorphous silica/aluminum interface region. A qualitative measure of the relative strengths of the two interface regions is possible by mea suring the difference in the amount of extrinsic defect relaxation. A quantitative measurement of the interfacial shear strength can be made by an indirect determination of the shear stress as the interface whe n extrinsic defect relaxation occurs.