Microstructural Sensitive Fatigue Modeling of Additively Manufactured Ti-6Al-4V

A common issue in powder-based Additive Manufacturing (AM) techniques is porosity. While process parameters can be controlled to limit this occurrence, complete elimination without post-processing is difficult. Because porosity can significantly affect fatigue behavior of AM parts, it is important to understand and model this material trait. In this study, the porosity in various Ti-6Al-4V specimens fabricated via Laser Engineered Net Shaping (LENS) was determined prior to fatigue testing. Void distribution and morphology was quantified. Fractography was performed to determine the specimen’s transition through crack initiation and propagation stages. These results were used to calibrate a microstructure-sensitive fatigue model for predicting the fatigue behavior of as-built and heat treated LENS Ti-6Al-4V.