A transmission electron microscopic study was made of the local response of a bi-material interface to an applied stress. It was noted that intersection with a dislocation which moved at an angle to the incoherent bi-material interface resulted in the creation of a dislocation line (extrinsic) defect at the interface. The intersection of the strain field of these defects with the interface was analogous to performing an atomic-scale tensile or shear test on the interface. The mechanical stability of this type of extrinsic defect was considered here as a possible indicator of the strength of an interface. An estimate of this stability was made by examining the degree of interfacial defect relaxation, as determined by the diffraction contrast in the transmission electron microscope, under an applied stress. A comparison was made here of the interface between sputter-cleaned Al and sputter-deposited amorphous SiO2 and of the interface between sputter-cleaned Al and sputter-deposited amorphous C. It was found that the amorphous C/Al interface region was much weaker than the amorphous silica/Al interface region. A qualitative measure of the relative strengths of the two interface regions was possible by measuring the difference in the amount of extrinsic defect relaxation.

E.D.McCarty, S.A.Hackney: Materials Science and Engineering A, 1995, 196[1-2], 119-28