Functionally Graded Nano-Composite for Gear Applications

The U.S. Navy is seeking improved durability, increased life and reduced maintenance for aircraft, particularly rotorcraft, by increasing the hardness of gears and bushings. They have suggested that the incorporation of nano-sized materials to create a functionally graded surface may provide this advantage. Such a compositionally graded structure offers the tooth surface offers the high hardness required to impart surface durability under very demanding contact conditions; the subsurface case region provides the strength gradient; and the core region with low to medium hardness of HRC 35-40 (VHN 345-390) provides a substrate with high toughness. Technology Assessment, in association with the University of Delaware and SSI Technologies has proposed to form a functionally graded surface during gear manufacture.