Effect of Blasting on the Fatigue Life of Ti-6Al-7Nb and Stainless Steel AISI 316 LVM

Among metallic biomaterials, titanium, its alloys and stainless steel AISI 316 LVM are of high importance and are widely used as surgical implants. Since these implants are designed to remain inside the body for a long time and are subjected to fluctuating high loads, it is important to consider fatigue properties. There are a variety of surface treatments that are used in metallic surgical implants with different aims: to improve biological response, wear properties, to modify surface finish, etc. In this work, the effect of blasting, that is one of the most commonly used surface treatments, on the fatigue life of Ti-6Al-7Nb alloy and stainless steel AISI 316 LVM was studied. Topography, roughness, surface defects, and microstructural changes were examined. Rotating bending (R=-1) fatigue tests were carried out in air, at room temperature, with a frequency of 43 Hz. σa – Nf curves were obtained for each material and surface condition. The fracture surface of tested samples were also characterized. Even though blasting introduced stress raisers, it improved the fatigue behavior of both Ti-6Al-7Nb and AISI 316 LVM samples.