An algorithm is presented to fit precipitates in atom probe tomographic data
sets as equivalent ellipsoids. Unlike previous techniques, which measure only
the radius of gyration, these ellipsoids retain the moments of inertia and
principle axes of the original precipitate, preserving crystallographic
orientational information. The algorithm is applied to study interconnected
gamma prime precipitates (L1_2) in the Gamma-matrix (FCC) of a Ni-Al-Cr alloy.
The precipitates are found to coagulate along -type directions.Comment: Accepted for publication in Scripta Materialia, added information
about local magnification effect