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.

Acknowledgements

The authors are grateful to FEI (Eindhoven), particularly to Mr. Wolfgang Ernst, for the opportunity to test the new Titan 80–300 equipped with a CEOS image C _s corrector. Torsten Scherer is thanked for the TEM sample preparation.