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Nanoscale lead and noble gas inclusions in aluminum: Structures and properties
Author(s) -
Johnson Erik,
Andersen Hans Henrik,
Dahmen Ulrich
Publication year - 2004
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.20097
Subject(s) - materials science , nanoscopic scale , transmission electron microscopy , grain boundary , aluminium , anisotropy , volume fraction , chemical physics , composite material , nanotechnology , microstructure , chemistry , physics , quantum mechanics
Transmission electron microscopy has been used for structural and physical characterization of nanoscale inclusions of lead and noble gases in aluminum. When the inclusion sizes approach nanoscale dimensions, many of their properties are seen to deviate from similar properties in bulk and in most cases the deviations will increase as the inclusion sizes decrease. Binary alloys of lead and noble gases with aluminum are characterized by extremely low mutual solubilities and inclusions will, therefore, exist as practically pure components embedded in the aluminum matrix. Furthermore, the thermal vacancy mobility in aluminum at and above room temperature is sufficiently high to accommodate volume strains associated with the inclusions thus leading to virtually strain free crystals. The inclusions grow in parallel cube alignment with the aluminum matrix and have a cuboctahedral shape, which reflects directly the anisotropy of the interfacial energies. Inclusions in grain boundaries can have single crystalline or bicrystalline morphology that can be explained from a generalized Wulff analysis such as the ξ‐vector construction. The inclusions have been found to display a variety of nanoscale features such as high Laplace pressure, size‐dependent superheating during melting, deviations from the Wulff shape displaying magic size effects, a shape dependence of edge energy, and so on. All these effects have been observed and monitored by TEM using conventional imaging conditions and high‐resolution conditions in combination with in‐situ analysis at elevated temperatures. Microsc. Res. Tech. 64:356–372, 2004. © 2004 Wiley‐Liss, Inc.