GOALI/Collaborative Research: Integrated Microstructure and Melt Pool Dimension Control for Electron Beam Additive Manufacturing

GOALI合作研究项目的目标是为电子束添加剂制造中熔池尺寸和微观结构的集成控制提供指导。电子束添加剂制造是一类新兴的制造工艺，通过局部熔化金属并逐层建立几何特征。该方法将用有限元模拟电子束沉积，并以近似分析模型为指导，该模型假定该过程以热传导为主。这使得能够快速了解结果作为过程变量变化的函数的趋势(通过使用近似分析模型)，从而确定要通过有限元更准确地建模的关键案例。模拟结果将在电子束功率、行进速度和材料进给速率的大范围内(高达5倍)提供，并将指导行业和政府合作者进行的关键实验的选择。模型和实验将包括通过电子束在零件表面上的快速移动来局部调整熔池内和周围的温度的影响。如果成功，这项研究的主要好处将是为这些制造过程开发同时控制熔池几何形状和微观结构的实用基础。由于熔池几何形状可以随着部件的建立而被监控和控制，因此通过控制熔池几何形状间接控制微观结构可以大大减少获得所需微观结构所需的试验次数。这将是对用于航空航天和其他商业应用的电子束制造工艺的鉴定和广泛使用的重大贡献。研究活动将与两所学术机构正在进行的教育研究项目相结合。

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.