Fatigue behavior of beta titanium alloys

Abstract

The use of titanium in several industries has been increasing in recent years due to a number of single features. The biocompatibility property makes it suitable for orthopedic implant industry, working in the replacement of worn and broken components. In aerospace, its high specific strength allows the application in the fuselage and jet engine of aircrafts, space rockets and satellites. The alpha+beta Ti-6Al-4V alloy is the most commercially used one, offering a good balance between strength, ductility and corrosion resistance. More recently, beta alloys aroused a great interest due to the low modulus of elasticity, good mechanical properties and better biocompatibility. Regarding the fatigue performance, the alpha+beta alloys have been extensively studied, whereas the study of the behavior of beta alloys is still very incipient. The understanding of the influence of structural/microstructural features on fatigue crack initiation, as well as the overall process that leads to a failure under fatigue, is of great importance for designing components that employ these materials. Thus the purpose of this work is to evaluate the mechanical behavior and the micromechanisms of fatigue crack initiation in two beta titanium alloys: I) a newly developed one for landing gear applications in aerospace industry (Ti5553); and II) one of interest of the orthopedic implant industry (TMZF). (AU)