Oxygen diffusion through titanium and other HCP metals

Wu, Henry

Permalink

https://hdl.handle.net/2142/45277 Copy

Description

Title

Oxygen diffusion through titanium and other HCP metals

Author(s)

Wu, Henry

Issue Date

2013-08-22T16:34:25Z

Director of Research (if dissertation) or Advisor (if thesis)

Trinkle, Dallas R.

Doctoral Committee Chair(s)

Trinkle, Dallas R.

Committee Member(s)

• Averback, Robert S.
• Bellon, Pascal
• Ertekin, Elif

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Titanium
• Oxygen
• Diffusion
• Hexagonal Closed-Packed (HCP)
• Density Function Theory (DFT)

Abstract

Titanium alloys, due to their high tensile strength, low density, and excellent corrosion resistance, have great potential in aerospace and medical implant applications. However, Ti alloy properties are very sensitive to oxygen content and readily oxidizes at high temperatures. Ab initio density functional theory calculations are utilized to study the atomistic mechanism of oxygen diffusion in titanium as well as the effect of substitutional solutes on oxygen diffusivity. Oxygen is found to reside at three interstitials in alpha-titanium, the octahedral, hexahedral, and crowdion sites. Transitions between these interstitial sites form a complex diffusion network in which almost all pathways contribute to diffusion. The interaction energy between oxygen and 45 substitutional solutes are calculated and used to predict how each solute changes oxygen diffusion through titanium. Additionally, the energetics and diffusion pathways for oxygen in 14 other hexagonal closed-packed (HCP) elements are studied, revealing that in most HCP systems the ground-state for oxygen is not the large octahedral site.

Graduation Semester

2013-08

Permalink

http://hdl.handle.net/2142/45277

Copyright and License Information

Copyright 2013 Henry Wu

Owning Collections