Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Andrew J Allen

Physical Scientist, Materials Measurement Science Division

Research Interest

  • X-ray and neutron scattering-based microstructure characterization to address technological barriers in advanced materials development, for example:
  • Nanoparticle formation, assembly and interaction, for industrial, biomedical and environmental health applications (including RM development in collaboration with National Cancer Institute).
  • Structure-property relationships in films, coatings and energy materials, including high-k dielectric films, thermal barrier coatings and solid oxide fuel cell materials.
  • Fundamentals of cement hydration, including the effects of additives and environmental conditions on concrete used in the nation's infrastructure.
  • In operando characterization of selective gas sorption phenomena in advanced sorbent materials, and precipitation kinetics in additive manufactured alloys.
  • X-ray photon correlation spectroscopy (XPCS) characterization of mesoscale equilibrium and non-equilibrium dynamics.

     

Postdoctoral Research Opportunities:

 

Microstructure of Energy Conversion, Storage, and Additive Manufacturing Materials

(Research Opportunity no. 50.64.31.B7417):

Control of microstructure, internal dynamics and chemistry is of primary importance in determining the performance and viability of solid oxide fuel cells, hydrogen fuel cells, carbon capture materials, and other systems that advance the hydrogen economy, promote US energy independence, or simply advance the Nation’s industry, e.g., through Additive Manufacturing.  The relevant scale range for void and phase microstructure (e.g. interfacial morphology, sintering or annealing), as well as for chemical site reactivity (e.g., combustion, reforming, corrosion) extends from the micrometer down to the sub-nanometer scale regime.  Our goal is to develop in operando measurement methods to quantify full three-dimensional void and phase microstructures and dynamics, including changes during service life and dependence on processing conditions.  These issues apply, e.g., to the electrodes and electrolyte of a SOFC; to the interfaces between them; and to any separate fuel-reforming hydrogen storage, or carbon dioxide capture material, where the microstructure must be related to the reaction site kinetics and to changes in site reactivity during service life.  This opportunity will address these interconnected issues by utilizing unique instrumentation, developed by NIST and its collaborators, and located at the Advanced Photon Source, the National Synchrotron Light Source II, and the NIST Center for Neutron Research. Opportunities exist for investigating novel energy materials and devices including batteries, solid oxide fuel cells, energy harvesting devices, photovoltaics, and additive manufactured components.

For more information...

Carbon (CO2) Capture Materials
(Research Opportunity no. 50.64.31.B8183):

Many industrial processes generate CO2 as a by-product, which is released to the atmosphere and contributes to global warming.  Clean, low-CO2 emission technology, which requires carbon capture (CO2 removal from flue gas by solid-state sorbents), is critical to meet our Nation’s energy and manufacturing needs in an environmentally sustainable manner.  Similarly, CO2 adsorption in shale minerals during enhanced oil and gas recovery will also play a critical role.  Low CO2 emission technology depends on transient gas/solid material interactions.  Such interactions cannot be inferred from initial or final state materials property measurements such as sorbent microstructure, but must be measured in situ during the sorption or release process.  This project focuses on the design, construction, and application of a suite of in situ measurement platforms for use with NIST’s state-of-the-art neutron and synchrotron X-ray scattering facilities, capable of interrogating critical carbon capture properties across the range of candidate CO2 sorbent solid materials, as well as oil and gas shales.  Measurements using the platform suite will focus on in situ determination of changes in structure, microstructure, atomic bonding, and dynamics in sorbent materials during the sorption and release of CO2 under controlled conditions of temperature, pressure, humidity, and atmosphere.  X-ray or neutron diffraction analysis and thermogravimetric analysis will be carried out in situ with samples that are simultaneously undergoing evolved gas analysis.

 

Awards

    •    Department of Commerce Silver Medal, Group Award, 2016
    •    Main Editor, Journal of Applied Crystallography, 2014-present
    •    Plenary Speaker, 15th International Conference on Small-Angle Scattering, Sydney, Australia, 2012
    •    Department of Commerce Bronze Medal Award, 2009
    •    Department of Commerce Silver Medal, Group Award, 2008
    •    Best Paper Award, Journal of Thermal Spray Technology, Volume 14, 2005
    •    Co-Editor, Journal of Applied Crystallography, 2002-2014
    •    NIST Bronze Medal, Group Award, 1998
    •    Best Paper Award, International Thermal Spray Conference, France, 1998
    •    Advisory Editor, Journal of Physics: Condensed Matter, 1991-96
    •    Open Exhibition Scholarship, Oxford University, 1974-1977

Publications

Disordered Heterogeneous Materials

Author(s)
Andrew J. Allen
This chapter describes the use of diffraction-based methods to characterize amorphous or disordered heterogeneous materials. Quantitative materials

Simulation of TTT curves for additively manufactured Inconel 625

Author(s)
Carelyn E. Campbell, Greta Lindwall, Eric Lass, Fan Zhang, Mark R. Stoudt, Andrew J. Allen, Lyle E. Levine
The ability to use common computational thermodynamic and kinetic tools to study the microstructure evolution in Inconel 625 (IN625) manufactured using the
Created October 9, 2019