Lattice images of inert gas bubbles in aluminium

Recent electron diffraction studies of a number of fcc metals implanted with inert gas ions have revealed that argon, krypton and xenon form room-temperature, solid, fcc precipitates (referred to as bubbles) epitaxial with the metal. We report on the use of high-resolution, phase contrast electron microscopy to produce one and two dimensional lattice images of room temperature solid argon and xenon in ion implanted aluminium. The images reveal clearly a high degree of crystalline perfection in many bubbles with a lattice parameter of 5.16 Å for the argon and 6.04 Å for the xenon. In the case of the Ar/AI system we also report on the anomalous thermal behaviour of the bubbles as deduced from diffraction measurements over the range ~80 to 800 K.