Phase Transformation Strengthened Disk Alloy for Commercial Application

TSNA-C is a nickel-based disk alloy designed around the familiar gamma/gamma-prime superalloy microstructure, but augmented by local phase transformation (LPT) strengthening that activates under creep. During high-temperature service, specific superlattice stacking faults become sites for controlled atomic-scale transformations, which harden those faults, suppress shear pathways (including microtwinning), and slow the mechanisms that typically degrade lifespan due to creep. This fault-level reinforcement is paired with a commercial-ready composition window tuned to balance transformation strengthening with forgeability and heat-treat response, enabling integration into powder-metallurgy routes such as Hot Isostatic Pressing, forging, and standard thermal processing. In NASA development, TSNA alloys formed the expected gamma/gamma-prime microstructure and preliminary tensile and fatigue-crack-growth evaluations at elevated temperature were within acceptable ranges for disk materials. Additionally, phase-stability checks after long-duration exposures showed no deleterious topologically close-packed (TCP) phase formation. Together, properties provide a disk alloy that can sustain higher hot-section demands with a balanced property profile, while fitting the workflows and cost expectations familiar to engine OEMs and suppliers. Forged variants demonstrated markedly improved high-temperature creep behavior, motivating a commercial composition that balances processability with fault-level strengthening. This technology is assessed at a Technology Readiness Level (TRL) 5 and is available for patent licensing. High-temperature rotating machinery depends on nickel-based superalloys, such as Inconel®, that can endure sustained stress in hot sections without creeping out of tolerance. However, modern nickel-based superalloys cannot keep up with advancements in efficiency and temperatures of proposed turbine engines. As such, engineers at NASA’s Glenn Research Center have developed a novel phase transformation strengthened disk alloy (known as Transformation Strengthened NASA Alloys or TSNA-C) engineered specifically for commercial use. It targets core limitations by raising durability at elevated temperatures while maintaining workability using established disk manufacturing methods. This material was developed for hotter compressor-exit environments and efficiency goals that push disks closer to the thermal ceiling of modern alloys. The approach strengthens the material where creep begins, using atomic-scale transformations at specific faults to resist time-dependent deformation and extend usable life. The result is a disk alloy intended to deliver predictable performance in the hottest stages and integrate cleanly with HIP/forge/heat-treat workflows. Internal NASA testing has shown improved temperature capabilities compared to nickel-based superalloys Inconel®, ME3, and Low Solvus High Refractory (LSHR).