Combining Thermal Modeling Techniques for Build Strategy Selection in Additive Manufacturing of Ti-6Al-4V

 Metal additive manufacturing (AM) represents a set of technologies with great promise for advanced manufacturing capability, but development of physical models is needed to rigorously understand the relationship between process parameters and part outcomes in order to successfully and consistently build real-world parts. Laser powder bed fusion (LPBF) is a process that is relatively well-studied within metal AM, while laser hot wire AM (LHWAM) is a newer process within the field. For both processes, laser scan strategy and overall build strategy is influential for key process outcomes such as as-built part geometry, microstructure, and residual stresses. For LPBF, scan strategy investigations can be carried out with the aid of existing process knowledge, but for LHWAM, basic process development is needed before comparison and optimization of scan strategies is possible. In this work, a novel scan strategy for creating large melt pools in LPBF is systematically mapped across a high-dimensional parameter space, using rapid semi-analytical modeling. Applying tools originally developed for LPBF to the LHWAM process, process development through thermal and thermomechanical modeling of the LHWAM process is used to guide process parameter and scan strategy selection across parts ranging from single beads to complex three-dimensional parts. Rapid modeling tools to support build strategy selection are developed, including process maps, non-dimensionalized curves, and surrogate models, in addition to the use of commercial modeling tools. These tools were tested over the course of building multiple geometry types, with the results applicable to future process development efforts for other materials and processes.