HRTEM study of a non-equilibrium Al–Pb interface

Abstract

A non-equilibrium Al–Pb interface was characterized by high-resolution TEM imaging in a spherical aberration-corrected TEM. Al samples containing 1 at.% Pb in the form of nanometre-sized inclusions were produced by high-energy ball milling. A Pb nanoparticle located at the very thin edge of an electron-transparent foil was melted under the influence of the electron beam during a high-resolution TEM study and formed an interface with the Al matrix. After resolidification, the crystallographic orientation relationship between the Pb nanoparticle and the Al matrix was determined to be: [001]Pb ‖ [011]Al, Pb ‖ Al, [110]Pb ‖ Al. This orientation relationship yields a misfit of 33.6% with respect to the Pb lattice and 25% with respect to the Al lattice. The misfit is accommodated in the form of interfacial dislocations on about every fourth Al plane. Burgers circuits drawn around these defects reveal a 0/2 edge dislocations to accommodate the misfit. This permits a direct comparison with the atomic structure of ‘classical’ cube-on-cube oriented Pb inclusions in Al. From these observations it is concluded that the ‘classical’ cube-on-cube orientation relationship is the energetically favoured configuration since the lowest number of misfit dislocations are needed to accommodate the misfit.