Effects of the microstructural characteristics of a metastable β Ti alloy on its corrosion fatigue properties

In the field of biomedicine, preventing the corrosion fatigue of metallic biomaterials for use in hard tissue replacement implants is of paramount importance. Corrosion fatigue of implants is caused by their contact with body fluids, as well as cyclic stresses resulting from body movements. The metallic biomaterials most widely used today are titanium alloys. It is a well known fact that the mechanical behavior of titanium alloys is determined by their chemical composition and thermomechanical processing. This study involved an evaluation of the influence of the microstructure on the corrosion fatigue of Ti–35Nb (wt.%) alloy samples in NaCl 0.9% solution. The samples were subjected to two different cooling rates from β phase field temperatures. The distinct cooling rates resulted in microstructures composed of β and α″ phases (160 °C/s) and α, β and ω phases (0.04 °C/s). The samples were characterized microstructurally by optical, scanning electron and transmission electron microscopy and X-ray diffraction. Their high-cycle corrosion fatigue properties were evaluated based on fatigue tests in NaCl 0.9% solution, under stresses ranging from 150 to 450 MPa. The results suggest that the furnace cooled sample showed lower corrosion fatigue.