W. Hofmeister, L. Costa, J. Steinhoff, UT Space Institute, Tullahoma, TN; R. A. Hafley, K. M. Taminger, NASA Langley Research Center, Hampton, VA
Electron beam freeform fabrication (EBF3) with wire as a feedstock offers tremendous potential for in space fabrication and repair. In addition, the technique is useful for prototyping metallic structures on earth. In this paper we address some of the processing issues of EBF3 both in earth gravity and low gravity in order to understand and improve the control of shape and microstructure in free form deposits. We will present strategies for modeling the various physical phenomena responsible for heat and mass transfer and fluid flow within the e-beam generated molten pool. The considerations will elucidate the advantages and limitations of the electron beam process for in-space fabrication and guide the realization of useful structures with good microstructural properties.
Summary: Electron beam freeform fabrication (EBF3) with wire as a feedstock offers tremendous potential for in space fabrication and repair. In addition, the technique is useful for prototyping metallic structures on earth. In this paper we address some of the processing issues of EBF3 both in earth gravity and low gravity in order to understand and improve the control of shape and microstructure in free form deposits. We will present strategies for modeling the various physical phenomena responsible for heat and mass transfer and fluid flow within the e-beam generated molten pool. The considerations will elucidate the advantages and limitations of the electron beam process for in-space fabrication and guide the realization of useful structures with good microstructural properties.
