Diffusion Of Oxygen In Titanium

Abstract

The oxidation of titanium alloys involves both the growth of a stable oxide and the diffusion of oxygen into titanium. Oxygen, one of the most effective solid solution strengtheners in titanium, will produce a hardness profile similar to the concentration profiles produced by diffusion into the metal. Microhardness testing can be used to measure these profiles and work out the diffusivity of oxygen in titanium. A laboratory experiment has been developed in which commercially pure titanium is annealed in air, the microhardness profiles are obtained, and the results are analyzed to obtain the activation energy for diffusion. The value obtained was close to that for tracer selfdiffusion in α-Ti. This inexpensive experiment, based on scientific literature from the 1950s, gives the students hands-on experience with the experimental methods and interpretation of the data used to study this very basic materials behavior.