Project title: Why is Ti6242 susceptible to cold dwell fatigue, but Ti6246 is not?
Supervisors : Adrian Sutton (Imperial College, Physics), Peter Haynes (Imperial College, Physics & Materials)
Collaborators: David Dye (Imperial College, Materials), David Rugg (Rolls-Royce)
Titanium alloys are used extensively in the aerospace industry due to their high strength to weight ratio, and corrosion resistance [1, p.15]. Despite these virtues their use is hampered by their susceptibility to a failure mechanism called cold dwell fatigue (CDF), a longstanding industrial problem that costs the aerospace industry millions in over-conservative design and extensive testing for each commercial aircraft [1, p.279].
This project is an investigation of the role of atomic diffusion in the susceptibility of certain Ti alloys to CDF. Density functional theory (DFT) will be used to model the behaviour of point defects in bulk Ti. This data will be used to calculate how their presence affects the self-diffusivity of Ti, which can in turn be related to the creep rate variation via continuum models.
 G. Lutjering, J. C. Williams, “Titanium” 2nd edition, Springer (2007).