Interphase interfaces of AuAg and AuPd

Abstract

The interfacial microstructure of {001} twist interphase boundaries in AuAg and AuPd bicrystal thin film couples has been investigated by transmission electron microscopy. The bicrystal thin film couples were produced by a new technique described herein. Examination of the bicrystal films showed that orthogonal grids of interphase boundary dislocations of 〈110〉 type formed in the {001} low-angle twist interphase boundaries of both AuAg and AuPd systems. The interfacial dislocations of AuAg interphase boundaries are similar to those of AuAu, i.e., almost screw in character. In AuPd interphase boundaries, the interfacial dislocations show the mixed edge and screw character as expected. The high-angle {001} twist interphase boundaries of AuAg and AuPd were also studied. The concidence lattice concept was applied to study the high-angle twist interphase boundaries. Several critical angles were obtained for both AuAg and AuPd systems. Orthogonal grids of secondary dislocations were observed in the {001} twist interphase boundary of AuAg thin film couples with the twist angle near 36.9°, the critical angle corresponding to the coincidence of ∑ = 5. Experimental evidence of the interfacial dislocation structure of the high-angle twist interphase boundaries of AuPd has not yet been obtained. However, diffraction patterns do show the coincidence character in agreement with what was predicted.