Structure determination and structure refinement of Al2CuMg precipitates by quantitative high-resolution electron microscopy

The structure of the S-phase (Al2CuMg) precipitate in an Al matrix has been determined by using a combination of image processing, quantitative image comparison, and automatic refinement of imaging and structural parameters. A method for comparing images with unknown origin relationship while quickly estimating a possible translation of the origin is outlined. The optimization algorithm used in the structure determination utilizes space group symmetry, which is deduced from the crystal-zone axis and reduces the number of free parameters.