Abstract
In this paper we present a combined experimental and theoretical study of misfit dislocations in metal‐ceramic interfaces. The goal is to reveal the atomic structure of the cores of misfit dislocations and relate it to the bonding strength between the two materials. Two interfaces in the niobium-sapphire system corresponding to different interface planes between the Nb and Al2O3 crystals, (0110)Al2O3|(112)Nb and (0001)al2O3 |(111)Nb, have been investigated. Misfit dislocations were observed to be present in Nb with no stand-off away from the interface, and their cores were investigated using high resolution electron microscopy. Atomistic studies of these misfit dislocations have been carried out using a very simplified model for both the ceramic crystal and the atomic interactions across the interface. A good agreement between the calculated and observed core structures has been attained for certain values of the cohesive strength across the interface and the results are discussed in terms of establishing relationship between the atomic structure of misfit dislocations and interfacial cohesion.
