Super Superelastic Alloys
2014 R&D 100 Winner
Corrosion, denting, abrasive wear and fatigue often lead to life-limiting bearing and gear failure in harsh conditions. Existing materials, such as hard steels, are prone to corrosion and rust; ceramics are non-conductive, difficult to manufacture and brittle; and superalloys are soft and susceptible to wear and damage. Working with Abbott Ball Company, NASA’s Glenn Research Center has successfully developed a set of methods to create high-performance alternatives to conventional bearing materials. Superelastic Intermetallic Nickel Titanium Alloys and Manufacturing Techniques for Advanced Bearing Applications builds on work that began in the 1950s to develop nickel-titanium alloys for military use. In 2004, the Abbott Ball-NASA partnership began to develop and refine the binary compound 60NiTi, which contains 60% nickel and 40% titanium. Bearing-grade 60NiTi is manufactured via a patented high-temperature powder metallurgy (PM) process. Pre-alloyed NiTi alloy powder is hot isostatic pressed into various shapes and sizes, such as spherical ball blanks, that are then ground, polished and lapped. Because the PM process yields ball blanks that have isotropic mechanical properties, high-quality bearing balls can be readily produced. The finished result has a variety of desirable properties: immunity to corrosion and rust, large strain endurance (greater than 5%), high hardness, up to 20% lighter than steel and wear- and shock-resistance.
The Superelastic Intermetallic Nickel Titanium Alloys and Manufacturing Techniques for Advanced Bearing Applications Development Team
Christopher DellaCorte, Principal Developer, NASA Glenn Research Center
Glenn Glennon, Principal Developer, Abbott Ball Corporation