TENSILE/TORSIONAL FATIGUE OF BIOMEDICAL TITANIUM ALLOYS

摘要

Fatigue tests under tensile/torsional stress of a biomedical titanium alloy, i.e. Ti-6Al-7Nb alloy, were carried out using a hydraulic Servo testing machine with axial and torsional loading units. S-N plot was discussed together with the results of tensile fatigue test and torsional fatigue test through the effective stress, which is introduced by von Mises-type yield condition. Change of the gradient of S-N plots suggests that the boundary of low cycle fatigue and high cycle fatigue. Observation of fractured surface was conducted using a scanning electron microscope. Morphology of ruptured surface were varied with types of the stress and magnitude of the stress. No clear striation was observed in this study.