Titanium alloys do not exhibit good seizure toughness. In general, a surface treatment must be applied if the component is subjected to sliding contact. For surface hardening, it is well known that oxygen and nitrogen treatments can be used because they are easily available, inexpensive elements. However, these treatments cause the fatigue strength to decrease which is a problem.
The reason for the fatigue strength decrease due to oxygen diffusion treatment is residual tensile stress on the surface. Shot peening is an effective technique to improve the fatigue strength of oxygen diffusion treated titanium. This report details the effects on fatigue strength due to surface treatments such as notch and shot peening.