GRC103y: Nano-Yttria Strengthened C103 for Additive Manufacturing

NASA's ODS-MEA maintains properties up to 1100°C and is not susceptible to deleterious phase changes when exposed to extreme temperatures, an issue ubiquitous to Ni- based superalloys such as Inconel-625 and Inconel-718. Yttria particles are dispersed throughout the alloy to maximize strength and creep resistance at high temperatures using a novel fabrication technique. This technique employs an acoustic mixer to stir nano-scale Yttria oxide powder within a metallic matrix powder, creating a film of Yttria surrounding the larger metallic powder particles. Solid components are then produced from this mixture via SLM, during which the laser disperses the Yttria particles throughout the microstructure. Ultimately, the process eliminates the many expensive and time-consuming steps in the production of ODS alloys via traditional mechanical alloying. NASA's process has been shown to fabricate components with 10x improvement in creep rupture life at 1100°C and provides a 30% increase in strength over what is currently possible with 3D printed parts. The new ODS-MEA composition may find applications where ODS alloys are currently used (e.g., those involving extreme thermal environments). Applications may also include areas where such properties are desirable but the resource-intensive nature and/or inability to produce highly complex geometries via conventional processes ultimately renders their use uneconomical or infeasible. Such uses include gas turbine components (for which increasing inlet temperature enables improved efficiency) for power generation, propulsion (rockets, jet engines, etc.), industrial processes, nuclear energy applications, and sample preparation equipment in the mining and cement production industries, among many others.

NASA's new Ni-based superalloy uses a powder metallurgy (PM) composition that inhibits the deleterious gamma-prime to gamma-phase transformation along stacking faults during high temperature creep deformation. Ni-base superalloys have excellent high temperature properties, mostly due to the presence of coherent precipitates. At higher temperatures, these precipitates are defeated by the diffusional shear dislocations producing intrinsic and extrinsic faults. Recent studies have found that, during deformation of turbine disk alloys at high temperature, Co, Cr, and Mo segregate to these faults (removing Ni and Al) inside the strengthening precipitates of these alloys. This represents a local phase transformation from the strengthening precipitate to the weaker matrix phase. Therefore, this elemental segregation significantly weakens the ability of a precipitate to withstand further deformation, producing faster strain rates in the alloy at higher temperatures. This invention presents a solution to prevent this type of segregation along these two faults to improve the creep properties of turbine disks and similar Ni-based alloys. By alloying a specific amount of eta phase formers (Ti, Ta, Nb, and Hf), the phase transformation to can be eliminated along 2-layer extrinsic stacking faults (SESFs) in precipitates without precipitating bulk eta phase. Also, by adding a certain amount of D019 formers (Mo and W), the phase transformation to can be mitigated along 1-layer intrinsic stacking faults (SISFs) without producing bulk sigma phase. This alloy composition incorporates both strengthening methods for use in jet turbine disks, though the composition has applications in other high-stress and/or high-temperature environments as are found in power plants, space launch systems, and other critical structural applications.

Dispersion Enhanced Aluminum Alloys improve the additive manufacturing performance of high-strength aluminum alloys by modifying the alloy powder with uniformly dispersed nano-sized ceramic particles. Building on the dispersion and acoustic mixing methods developed during the creation of NASA Glenn's GRX-810 technology, researchers use an acoustic field to attach nanoscale alumina dispersoids to the surface of each aluminum alloy powder particle. During mixing, acoustic energy creates rapid micro-vibrations that cause the alumina particles to collide with the metal powder, embed against its surface, and distribute into a uniform shell that surrounds each particle. This produces a composite powder in which every aluminum particle carries its own evenly spaced ceramic nucleation sites. When the composite powder is delivered into an additive manufacturing process such as laser powder bed fusion or directed energy deposition, the aluminum alloy melts while the alumina dispersoids remain solid due to their significantly higher melting temperature. As the molten pool flows and mixes, the dispersoids remain suspended throughout the liquid region. During solidification, these solid particles interrupt grain growth and serve as nucleation points that promote the formation of fine equiaxed grains. This refined microstructure distributes thermal stresses more uniformly and disrupts the crack initiation mechanisms that typically occur in high-strength alloys like AA 2050. By stabilizing the alloy during solidification, the technology enables these advanced materials to be printed with greater reliability, improved geometric control, and more consistent mechanical behavior across the final product. The enhanced alloy technology is available for patent licensing.

Shape memory alloys (SMAs) are metals that can return to their original shape following thermal input. They are commonly used as functional materials in sensors, actuators, clamping fixtures and release mechanisms across industries. SMAs can suffer from dimensional/thermal instability, creep, and/or low hardness, resulting in alloys with little to no work output in the long term. To combat these deficiencies, NASA has developed a process of incorporating nanoparticles of refractory materials (i.e., carbide, oxide, and nitride materials with high temperature resistance) into the alloys. Using various processing methods, the nanoparticles can be effectively mixed and dispersed into the metal alloys as shown in the figure below. In these processes the SMA and refractory material powder is mixed and the refractory nanoparticles incorporated through extrusions, melting, or directly used in additive manufacturing to create parts for applications across the aerospace, automotive, marine, or biomedical sectors. The nanoparticle dispersion is a controllable method to strengthen the SMAs, increasing the hardness of the alloys, reducing the impact of creep, and improving the overall dimensional and thermal stability of the alloys. The related patent is now available to license. Please note that NASA does not manufacture products itself for commercial sale.

In-situ alloyed, additively manufactured GRCop components are produced by mixing elemental copper, chromium, and niobium powders and then selectively laser melting the powder mixture using powder bed fusion additive manufacturing. During laser melting, the chromium and niobium powders react to form Cr2Nb precipitates in the molten state, which are then dispersed in the pure copper matrix upon solidification. This dispersed precipitate phase is encapsulated within the pure copper matrix upon solidification, resulting in the characteristic microstructure of GRCop alloys with high thermal conductivity from the copper combined with superior mechanical properties from the precipitates. Optimization of process parameters like laser power has enabled up to 89% conversion of the constituent elements into Cr2Nb precipitates. The achieved rapid cooling rates of ~10^4-10^6 K/s enable formation of fine Cr2Nb precipitates around 0.1-1 micrometers in size. The technology is currently at a TRL 4, and NASA has developed and tested coupons of material using the new process. The related patent is now available to license. Please note that NASA does not manufacturer products itself for commercial sale.