Opportunity
The aerospace and power generation industries demand materials capable of withstanding extreme conditions, such as high temperatures, high speeds, and high stress. Traditional nickel-based superalloys, while effective, suffer from significant drawbacks including poor printability, susceptibility to cracking (e.g., solidification cracking, liquation cracking), and anisotropic mechanical properties. These limitations restrict their application in modern engineering, particularly in complex geometries like turbine blades. Additionally, the long development cycles and high costs associated with new materials further exacerbate the need for innovative solutions. The emergence of high-entropy alloys (HEAs) offers a promising alternative due to their unique mechanical properties, but existing HEAs often lack the necessary balance of strength, ductility, and isotropy required for critical applications. This patent addresses these challenges by introducing a novel multi-component HEA with nanoscale atomic self-ordering (NS-ASO) structures, fabricated via additive manufacturing (AM), to overcome the limitations of traditional superalloys and conventional HEAs.
Technology
The patent presents a groundbreaking multi-component HEA composed of cobalt (Co), nickel (Ni), chromium (Cr), aluminum (Al), titanium (Ti), molybdenum (Mo), tantalum (Ta), and niobium (Nb). The alloy is designed with a nanoscale atomic self-ordering structure (1–5 nm) achieved through selective laser melting (SLM), a form of additive manufacturing. This innovation leverages the rapid cooling rates of SLM to create near-void-free alloys with exceptional density (>99.998%) and mechanical properties. The NS-ASO structures are coherent with the matrix, enabling dislocation transmission across boundaries without crack nucleation. Key technological advancements include:
- Compositional Design: The alloy’s formula (CoₐNi₆Cr₆Al₄Ti₆Mo₇Ta₈Nb₉) is optimized for high-temperature performance, with elements like Ti, Mo, Ta, and Nb replacing tungsten to reduce density while maintaining microstructure integrity.
- Additive Manufacturing: SLM parameters are finely tuned to eliminate defects like lack-of-fusion pores or keyholes, ensuring isotropic properties in both building direction (BD) and scanning direction (SD).
- Mechanical Performance: The alloy exhibits unprecedented strength-ductility synergy—ultimate tensile strength (~1.54 GPa) paired with uniform elongation (~22.5%)—and fatigue resistance superior to conventional alloys like IN718 or Ti-6Al-4V.
Advantages
- Exceptional Mechanical Properties: Combines ultrahigh strength (~1.54 GPa) with ductility (~22.5% elongation).
- Near-Void-Free Structure: Achieves 99.998% relative density via SLM, surpassing traditional methods.
- Isotropy: Eliminates anisotropy in mechanical properties across BD and SD directions.
- Printability: Resists cracking despite high Al+Ti+Nb+Ta content (>6 wt%), unlike conventional superalloys.
- Cost-Effective Production: SLM reduces processing time and material waste compared to casting/forging.
Applications
- Aerospace: Turbine blades, engine components requiring high-temperature resistance and fatigue life.
- Automotive: High-stress parts like exhaust systems or turbochargers.
- Nuclear Engineering: Radiation-resistant structural materials.
- Power Generation: Components for gas turbines or other high-stress environments.
