Fundamental Studies on the Formation of Protective Oxide Scales on Structural Metals and Alloys
Abstract
A collaborative theoretical/experimental program to understand the Reactive Element (RE) effect that is so effective in enhancing the oxidation resistance of Febase and Ni-base high temperature structural alloys is proposed. The theoretical program, in collaboration with Prof. M. Finnis (Imperial College London), will be concerned with calculating the band structure of sigma 7 Al2O3 bi-crystal boundaries containing Y, Zr, or Hf segregants (Y, Zr, and Hf are the most common REs for Fe-base and Ni-base structural alloys), and studying the mechanism(s) responsible for their effectiveness. Further, the atomistic mechanism(s) involved in grain boundary diffusion will be explored. For this, a post-doc from the research group of the PI, Prof. A. H. Heuer, will work with Prof. Finnis in the Imperial College Centre for Theory and Simulation of Materials. The experimental program, in collaboration with Dr. Farrel Martin of the Naval Research Laboratory, will be concerned with high temperature (1100°C to 1400°C) electrochemical impedance spectroscopy of the Al2O3 scales formed on a suite of gamma/gamma prime Ni-20 Al-5 Cr alloys containing 0.05 wt % of the Reactive Elements Y, Zr, or Hf. In addition to measuring the electrical conductivity and transference numbers of the scales, the dielectric properties will be determined in the frequency range 100 mHz to 400 MHz.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 27, 2018
- Source ID
- N000141812556
Entities
People
- Michael W. Finnis
Organizations
- Imperial College London
- Office of Naval Research
- United States Navy