Oak Ridge National Laboratory (ORNL) is utilizing its extensive expertise in neutron characterization of advanced materials together with resources such as the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) to solve challenging problems in additive manufacturing (AM). AM or three-dimensional (3-D) printing is a rapidly maturing technology wherein components are built by selectively adding feedstock material at locations specified by a computer model. The majority of these technologies use thermally driven phase change mechanisms to convert the feedstock into functioning material. Work is being conducted on AM technologies at the ORNL Manufacturing Demonstration Facility (MDF) sponsored by the US DOE's Advanced Manufacturing Office. The MDF is focusing on R&D of metal and polymer AM pertaining to in-situ process monitoring and closed-loop controls and implementation of advanced materials in AM technologies.