Innovative Powder Metallurgy-Hot Isostatic Pressing Process for Enhanced High Temperature Performance

Nuclear power is a key component to the portfolio of technologies necessary to quickly deploy clean, affordable, domestic energy sources in the United States, to meet our energy security and environmental goals. Advanced Manufacturing specifically powder metallurgy-Hot Isostatic pressing is a mature technology that can be readily deployed to produce high temperature material components for nuclear reactor applications with excellent room temperature mechanical properties, often performing better than forged or cast parts. However, the high temperature creep-fatigue performance of PM-HIP processed material needs to be improved to withstand structural damage due to thermal transients that these parts may experience during reactor operations. The objective of this Phase I project is to establish specialized protocols and limits for alloy chemistry, production and pre-conditioning of metal alloy powders. Furthermore, canning, degassing and, HIP processing protocols will be developed to provide improved high temperature performance necessary for service in advanced nuclear reactors. The approach will focus on inert powder handling operations designed to prevent exposure of powders to oxygen and other contaminants, as well as powder pre- processing by high energy cryomilling and rotary furnace degassing of selected compositions relevant to nuclear reactors. The goal of this effort will be to establish scalable PM processes capable of enhancing the high temperature performance of PM-HIPed materials. Powder metallurgy processes for production of consolidated alloys including 316L and A508 used for nuclear power applications will be developed based on our expertise in the areas of reactive metal processing, inert handling and conditioning and hot isostatic pressing. Powder conditioning methods will be designed for reducing powder contamination and improving microstructural uniformity. Sources for contamination resulting from the canning and degassing stages will be systematically studied and inert handling and enhanced degassing capabilities will be applied for production of inertly sealed canisters of specified alloys. The hot isostatic pressing process will be optimized via in-situ sensing of compact consolidation and results will be evaluated through extensive microstructural and mechanical testing. Finally, scalability of the developed protocols for large scale part manufacture will be assessed. The outcomes of Phase I and advancements in Phase II and Phase III of the project will provide solutions for processing contamination sensitive powder metal alloys relevant to the Department of Defense, electric power aerospace industries. It will result in enabling technologies for mass production of large-scale parts with improved performance compared to traditional materials.