Oral Presentation 24th Australian Conference on Microscopy and Microanalysis 2016

Advanced crystallographic analysis of atom probe tomography data (#111)

Andrew J Breen 1 , Alec C Day 1 , Nathan D Wallace 1 , Kelvin Y Xie 2 , Katharina Babinsky 3 , Anna V Ceguerra 1 , Sophie Primig 4 , Simon P Ringer 1
  1. The Australian Centre for MIcroscopy and Microanalysis, The University of Sydney, Sydney, NSW, Australia
  2. Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
  3. Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Leoben, Austria
  4. School of Materials Science & Engineering, The University of NSW, Sydney, NSW, Australia

Atom probe tomography (APT) is an extremely powerful microanalysis tool, capable of reconstructing the position and chemical identity of millions of atoms in 3D with sub nm spatial resolution. Crystallographic information contained within the data is particularly useful for the accurate calibration of the tomographic reconstruction [1, 2] as well as for characterising grain boundaries in crystalline materials [3]. Out of existing microanalysis techniques, APT provides the best opportunity to correlate changes in crystallography and chemistry in 3D at the nm scale. However, the finite resolution limit still presents a challenge for detecting crystallographic information within many industrially significant materials.

In this presentation, new advances in atom probe crystallographic signal detection tools will be presented that enable observation of the lattice structure within systems that were previously not possible. For the first time, a crystallographic analysis of boron carbide across a grain boundary will be demonstrated using APT. Boron Carbide exhibits desirable engineering properties, most notably its high hardness and density, making it excellent for use in body armor. However, analysis through APT has proven challenging due to low crystallographic-signal and unusual evaporation characteristics. The accuracy of misorientation measurements using atom probe will also be quantified using complementary transmission Kikuchi diffraction (TKD) data. This work highlights the exciting potential for atom probe crystallography studies to be applied to a wider range of material systems than ever before and opens the door to a range of new nanostructural analysis capabilities.    

Acknowledgements: The authors acknowledge the facilities and the scientific and technical assistance of the Australian Microscopy & Microanalysis Research Facility at the Australian Centre for Microscopy & Microanalysis at the University of Sydney. The authors would also like to especially thank Prof. Julie Cairney, Dr Pat Trimby and Dr Hongwei Liu for fruitful discussion.

  1. A.J. Breen, M.P. Moody, A.V. Ceguerra, B. Gault, V.J. Araullo-Peters, J.M. Cairney, S.P. Ringer, Restoring the lattice of Si-based atom probe reconstructions for enhanced information on dopant positioning, Ultramicroscopy, (In press).
  2. M.P. Moody, A.V. Ceguerra, A.J. Breen, X.Y. Cui, B. Gault, L.T. Stephenson, R.K.W. Marceau, R.C. Powles, S.P. Ringer, Atomically resolved tomography to directly inform simulations for structure–property relationships, Nat Commun, 5 (2014).
  3. V.J. Araullo-Peters, B. Gault, S.L. Shrestha, L. Yao, M.P. Moody, S.P. Ringer, J.M. Cairney, Atom probe crystallography: Atomic-scale 3-D orientation mapping, Scripta Materialia, 66 (2012) 907-910.