Analysis of fatigue properties and failure mechanisms of Ti6Al4V in the very high cycle fatigue regime using ultrasonic technology and 3D laser scanning vibrometry.

Accelerated fatigue tests with Ti6Al4V were carried out using a 20kHz ultrasonic testing facility to investigate the cyclic deformation behavior in the Very High Cycle Fatigue (VHCF) regime in detail. Beside parameters like the ultrasonic generator power and the displacement of the specimen, a 3D laser scanning vibrometer was used to characterize the oscillation and fatigue behavior of the Ti-alloy. The course of the S-N(f) curve at the stress ratio R=-1 shows a significant decrease of the bearable stress amplitude and a change from surface to subsurface failures in the VHCF regime for more than 10⁷ cycles.

Fatigue and cyclic deformation behaviour of surface-modified titanium alloys in simulated physiological media.

In this investigation, the cyclic deformation behaviour of the binary titanium alloys Ti-6Al-4V and Ti-6Al-7Nb was characterized in axial stress-controlled constant amplitude and load increase tests as well as in rotating bending tests. The influence of different clinically relevant surface treatments (polishing, corundum grit blasting, thermal and anodic oxidizing) on the fatigue behaviour was investigated. All tests were realized in oxygen-saturated Ringer's solution.

Deformation behaviour and damage accumulation of cortical bone specimens from the equine tibia under cyclic loading.

Despite its clinical importance, the fatigue behaviour of cortical bone has not been examined as widely as its static behaviour. In the present study, specimens from the tibiae of horses have been subjected to load-controlled single step tests. The cyclic deformation behaviour was described by the development of stress-strain hysteresis parameters over the lifetime.