Oral Presentation 24th Australian Conference on Microscopy and Microanalysis 2016

Quantitative chemical-structure evaluation of short-range order using  atom probe tomography (#110)

Ross K.W. Marceau 1 , Anna V. Ceguerra 2 , Andrew J. Breen 2 , Dierk Raabe 3 , Simon P. Ringer 2
  1. Institute for Frontier Materials, Deakin University, Geelong, VIC, Australia
  2. Australian Centre for Microscopy & Microanalysis, The University of Sydney, Sydney, NSW, Australia
  3. Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany
We present a quantitative analysis of short-range-order (SRO) alloy using atom probe tomography (APT) data by calculation of the generalised multicomponent (GM-)SRO parameters. This has been achieved by employing shell-based analysis of the three-dimensional atomic positions to determine chemically sensitive SRO information. An Fe-18Al (at.%) alloy has been used in an attempt to understand the nature of the so-called ‘komplex’ phase state (or “K-state”), which is common to other alloy systems having compositions at the boundaries of known order-disorder transitions and has been previously characterised by bulk, volume-averaged measurement techniques (e.g. X-ray and neutron scattering, Mössbauer spectroscopy) as having ‘heterogeneous SRO’. The accuracy of the current, APT-based method with respect to limited detector efficiency and spatial resolution is tested against modelled D03 ordered data. Improved information sensitivity is demonstrated through lattice rectification of the experimental APT data prior to GM-SRO analysis.