Thermally Stable Nanometals by Predictive Atomic Scale Interfacial Energy Reduction

Abstract

Nanocrystalline iron (Fe) alloys doped with 1 at.% zirconium (Zr), tantalum (Ta), and nickel (Ni), produced through high energy mechanical alloying, were investigated for microstructural stability. The results were consistent with theoretical predictions, indicating a decrease in stability with solute type in the following order: Zr, Ta, and Ni. Preliminary transmission electron microscopy (TEM) investigations of the most stable system, Fe-Zr, revealed the presence of 2.5 at.% Zr within the grain boundaries of the sample, confirming a thermodynamic tendency for stability. More specifically, Zr segregation was found to be inhomogenously distributed between grain boundaries of nanostructured regions. Such a distribution accounts for and provides a potential mechanism for the appearance of abnormal grain growth at elevated temperatures. Additional compositional profiling uncovered a new FCC phase, within the abnormally grown grains. This phase is coherent with the BCC Fe substrate matrix and has a lattice parameter of 8.5 A.

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 2011
Accession Number
ADA540264

Entities

People

  • Elizabeth C Dickey
  • Kris Darling
  • Laszlo J Kecskes
  • Li Jing
  • Zi-Kui Liu

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Boundaries
  • Crystal Structure
  • Density Functional Theory
  • Electron Microscopy
  • Electrons
  • Energy
  • Grain Boundaries
  • Grain Growth
  • Grain Size
  • High Energy
  • High Resolution
  • Ion Beams
  • Materials
  • Materials Science
  • Metals
  • Microscopy
  • Transmission Electron Microscopy

Fields of Study

  • Materials science
  • Physics

Readers

  • Materials Science and Engineering.
  • Metallurgy
  • Nanocomposite Materials Science

Technology Areas

  • Microelectronics