The Usefulness of Conflicting Published Flow Stress Data: A Case Study with Ti 6Al 4V

Flow stress behavior of engineering alloys is a key aspect predicting alloy performance through manufacturing and service. There exist hundreds of published datasets for most of our common engineering alloys, but often these published data are in disagreement with each other. In the current study, we compare published flow stress data for a common aerospace alloy (Ti-6Al-4V) to shed light on the causes for disagreement in the literature. In particular, we consider variability in microstructure, composition, prior processing, and test methods as explanation for the variability in the flow stress curves. We also consider the impact that a wide spread of published flow stress behaviors may have on the usefulness of the materials data in various plasticity models (e.g., Johnson Cook) and finite element method process simulations. Data is pulled from published sources using Graph Grabber, and analysis of data includes conventional computational methods (primarily MatLab, Origin Pro). Axisymmetric deformation models using Ansys are employed for comparison of stress distribution as a result of varied material property input. Finally, we propose a path forward for using and interpreting conflicting datasets available in the literature for Ti-6Al-4V and other alloy systems. This project was conducted with the support of the Center for Materials Processing Data.