Local interface response to dislocation strain fields at the Al/SiO < inf> 2 and Al/C boundary region

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This work presents a transmission electron microscopy study of the local bimaterial interface response to applied stress. The intersection of a dislocation moving at some angle to the incoherent bimaterial interface with the interface results in the creation of a dislocation line defect (an extrinsic defect) at the interface. The intersection of the strain field of these defects with the interface is analogous to performing a tensile test or a shear test on the interface, but on the atomic scale. This paper will examine how the mechanical stability of this type of extrinsic defect can be a measure of the strength of the interface. A measure of this stability can be performed by examining the degree of interfacial defect relaxation, as determined by the diffraction 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 sputter-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 measuring 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 when extrinsic defect relaxation occurs. © 1995.

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Materials Science and Engineering A