Experimentally-Validated Model for Heat Treatment of 3D Printed Titanium

Ti-6Al-4V is a commonly-used alloy in aerospace and defense applications. Additive manufacturing (laser powder-bed fusion) has successfully been used to manufacture Ti-6Al-4V to lower material usage, reduce lead times, and create parts with complex geometries. ASTM standards dictate heat treatment procedures for traditionally manufactured Ti-6Al-4V, but the resulting microstructural changes on AM parts have not yet been modeled and are not completely understood. It is desired to create an experimentally-validated computational model that quantifies structure-property-process relationships for LPBF Ti-6Al-4V. During Phase I, a computational scheme will be developed to predict the effect of heat treatments on the microstructure of LPBF Ti-6Al-4V. Lab-scale samples will be produced using historically-successful print parameters. These samples will be heat-treated, and hardness, density, composition, and microstructure will be measured. During Phase II, tension and fatigue tests will be performed, and the microstructural model will be evaluated. Computer tomography will be used to observe microstructural changes and iterate the model. During Phase III, a plan will be generated to transition the results of the study to end-use applications in the additive manufacturing of near-net-shape parts for the US Army. An optimized heat-treatment process for L-PBF Ti-6Al-4V will be proposed based on computational optimization.