Volume Effects on the Fatigue Behavior of Additively Manufactured Ti-6Al-4V Parts

Abstract

Recent interest to implement additive manufactured parts into structural applications has created a critical need to better understand the fatigue behavior of these parts. Alloys such as Ti-6Al-4V are popular in the aerospace and biomedical industries due to their superior strength to weight ratio and biocompatibility. In these two industries, part sizes can range from very small surgical implants to large structural components, all of which are subjected to cyclic loading conditions. The fatigue behavior of additively manufactured parts may show more sensitivity to part size than their wrought counterparts due to the defects that are inherent to the fabrication process. This research investigates the sensitivity of additively manufactured Ti-6Al-4V parts to volume size by comparing the stress-life fatigue curves of three geometries with increasing gage volumes. Results indicate that additive Ti-6Al-4V parts show reduced fatigue lives because of an increase in surface or near-surface defects.