The objective of this Grant Opportunity for Academic Liaison with Industry (GOALI) collaborative research project is to provide guidelines for integrated control of melt pool dimensions and microstructure in electron beam additive manufacturing, a class of emerging manufacturing processes which build geometric features by locally melting metal and building it up layer-by-layer. The approach will be to model electron beam deposition by finite elements, guided by an approximate analytical model that assumes the process is dominated by thermal conduction. This allows rapid understanding of trends in results as a function of process variable changes (from use of the approximate analytical model), identifying key cases to model more accurately via finite elements. Simulation results will be presented across a wide range (up to a factor of 5) of electron beam powers, travel speeds and material feed rates and will guide the choice of critical experiments conducted by the industrial and government collaborators. Models and experiments will include the effects of local tailoring of temperatures in and around the melt pool by rapid movement of the electron beam across the part surface.
If successful, the primary benefit of this research will be its development of a practical basis for simultaneous control of melt pool geometry and microstructure for these manufacturing processes. Because melt pool geometry can be monitored and controlled as a part is built, indirect control of microstructure through the control of melt pool geometry can substantially decrease the number of trials needed to achieve a desired microstructure. This will represent a significant contribution toward the qualification and widespread use of electron beam manufacturing processes for aerospace and other commercial applications. Research activities will be integrated with ongoing educational research projects at both academic institutions.