| Beta titanium alloys are being investigated for orthopedic applications due to their lower moduli of elasticity, consequently reducing possible stress shielding effect which leads to bone loss adjacent to integrally-bonded implants. In the present study, cyclic four-point bending fatigue testing was conducted to study fatigue behaviour (initiation + significant crack growth) of a beta titanium alloy, Ti-12Mo-6Zr-2Fe (TMZF) and Ti-6Al-4V, an alpha + beta alloy prepared with sintered titanium porous coatings. Results showed that the Ti-6Al-4V alloy required greater number of cycles for observable fatigue crack initiation compared with the TMZF alloy. The characteristics of the cracks observed in both materials were similar as they all initiated at the particle-substrate sinter neck and developed transgranularly along certain crystallographic planes. The greater number of cycles to develop detectable fatigue cracks in Ti-6A1-4V alloys was believed to be due to the stronger crack propagation resistance of the lamellar alpha + beta structure.;Keywords: Beta Titanium, Fatigue, Cyclic four-point bending, Porous coating, Sintering, Orthopedic implants... |
