Integrated Computational Materials Design (ICME) of Co-based Cu-Be Alternative for Aerospace Bushing Applications

ICME within a systems design framework has been applied to the design and development of a new Co-based superalloy as a high-strength, wear-resistant material alternative to Cu-Be for highly loaded, unlubricated aerospace bushing applications. Co-based designs were developed that incorporated nano-scale L1₂ precipitation strengthening within a low coefficient-of-friction Co-Cr matrix for an enhanced combination of strength and wear resistance. The design is specifically optimized to achieve properties in large product sizes (4-inch thickness and greater) without the need for cold- or warm-working to meet the needs of larger aerospace bushings.

The design process included a systems approach with modelling, targeted experimental validation and characterization, and accelerated scale-up and manufacturing. Thermodynamic and process modeling tools were developed to enable alloy design and processing optimization, allowing property targets to be achieved in just two prototype iterations. The new design has demonstrated improved wear (in dry sliding conditions against alloy steel), galling, and axial fatigue resistance in coupon-scale and sub-scale bushing tests compared to baseline AMS4533 Cu-Be. A full-scale prototype of the design has been fabricated and the initial testing shows excellent properties and high promise for replacement of Cu-Be.