Best-Fit Ellipsoids of Atom-Probe Tomographic Data to Study Coalescence of Gamma Prime (L1_2) Precipitates in Ni-Al-Cr

TL;DR

This paper introduces an algorithm to fit atom probe data as ellipsoids, capturing detailed shape and orientation information of gamma prime precipitates in Ni-Al-Cr alloys, aiding the study of their coalescence behavior.

Contribution

The novel algorithm preserves crystallographic orientation by fitting precipitates as ellipsoids, improving upon radius-based methods for analyzing atom probe data.

Findings

Precipitates coagulate along <110>-type directions.

Ellipsoid fitting retains orientation and shape details.

Enhanced understanding of precipitate coalescence in alloys.

Abstract

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 <110>-type directions.