Scientists at the Department of Energy’s Oak Ridge National Laboratory have developed a groundbreaking technology for fabricating composite metal parts suitable for extreme environments in aviation, space, and energy industries. This additive manufacturing technique allows the creation of compositionally graded composite parts, transitioning from high-strength superalloys to refractory alloys without the need for welding.
The key to this innovative process lies in a special “sauce,” analogous to cooking. The “sauce” is a powder composed of a third transition alloy with lightweight or high-temperature properties. By using an additive manufacturing modality called directed energy deposition, the scientists deposit different powder compositions while changing the deposition rate. This way, they can smoothly transition from one alloy to another within the same part, enabling high-strength and high-temperature capabilities on each side.
Traditionally, structural components in extreme environments are made from a single alloy composition, which can be costly and compromise performance. Alternatively, welded parts from dissimilar materials are used, leading to abrupt interfaces and reduced performance. However, this new technique allows the creation of composite parts with tailored properties, overcoming welding issues and joining normally non-weldable superalloys with refractory alloys.
The team achieved this breakthrough by coupling computational thermodynamics with experimental data to design the non-linear gradient pathway. They used powders of Inconel 718 and C103, two alloys with incompatible properties that tend to crack when joined conventionally. With this method, they successfully combined the beneficial properties of both alloys.
The applications for this technology are vast, ranging from rocket engines, aerospace manufacturing, and fusion/fission reactor fabrication to marine-related uses and renewable energy systems. The ability to create customized components with optimal performance and reduced fabrication costs could revolutionize how extreme condition components are made.
Lead scientist Soumya Nag has filed a provisional patent application for the materials and manufacturing process involved. The research team, including Brian Jordan, Ke An, James Haley, Yousub Lee, and Jaimie Tiley, contributes cross-disciplinary expertise from ORNL’s various departments. Their work combines physical sciences, energy science and technology, neutron sciences, computing, and computational sciences.
Source: Oak Ridge National Laboratory