Study of coherence strain of GP II zones in an aged aluminum composite

Strain mapping using the geometric phase analysis (GPA) technique was applied to Al-GP II (Guinier-Preston) nanoscale precipitates, using both high resolution transmission electron microscopy (HRTEM) micrographs as well as the exit wave function (EWF) obtained by focal series reconstruction. The experimental strain results were compared with strain maps obtained from an atomic model which consisted of an Al supercell containing a GP II precipitate. It was built as a reference from literature data. The experimental results demonstrate a complex strain distribution and larger fluctuations than the reference strain maps. These differences were found to be partly a consequence of image artifacts produced by the technique as well as complex microstructural events which were present at the development stage studied. (c) 2012 Elsevier B.V. All rights reserved.