Bridging neutron total scattering and atom-probe tomography for resolving amorphous and nanocrystalline structures

Project: Research project

Description

We propose a new approach to integrate neutron total scattering and atom-probe tomography (APT) through the Reverse Monte Carlo (RMC) method for resolving amorphous and nanocrystalline structures with a great degree of accuracy. Total scattering allows for the analysis of long-range average structure from Bragg scattering as well as local- and medium-range atomic structure from diffuse scattering, providing a powerful tool to characterize disordered, nanocrystalline and amorphous materials. The RMC analysis of total scattering data has long been employed to produce atomic configurations that match the experimental measurement [1]. While RMC is a stochastic approach for producing atomic models, it is often used as a refinement technique which in practice means the success often depends on finding a suitable starting configuration of atoms (∼20,000). Therefore, a starting configuration that is as close to the "true" one is desirable to aid the RMC modeling. In this regard, APT is a perfect fit in providing such a realistic starting configuration from a small portion of the reconstructed atomic map comprising hundreds of millions of atoms [2]. The proposed approach will be tested in two representative case studies: one for modeling the amorphous structure of Zr-Cu metallic glasses and the other for characterizing the sub-nano to nanoscale structure of γ′ nuclei precipitating from model Ni-based superalloys.
StatusActive
Effective start/end date8/9/187/31/20

Funding

  • UT-Battelle, LLC, Oak Ridge National Laboratory (4000164554//DE-AC05-00OR22725)
  • Department of Energy (4000164554//DE-AC05-00OR22725)

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nanostructure (characteristics)
tomography
neutrons
probes
scattering
atoms
configurations
amorphous materials
heat resistant alloys
metallic glasses
atomic structure
Monte Carlo method
nanocrystals
nuclei