STP1542

    Resilient and Corrosion-proof Rolling Element Bearings Made from Superelastic Ni-Ti Alloys for Aerospace Mechanism Applications

    Published: Oct 2012


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    Abstract

    Mechanical components (bearings, gears, mechanisms) typically utilize hard materials to minimize wear and attain long life. In such components, heavily loaded contact points (e.g., meshing gear teeth, bearing ball-raceway contacts) experience high contact stresses. The combination of high hardness, heavy loads, and high elastic modulus often leads to damaging contact stress. In addition, mechanical component materials such as tool steel or silicon nitride exhibit limited recoverable strain (typically less than 1 %). These material attributes can lead to Brinell damage (e.g., denting), particularly during transient overload events such as shock impacts that occur during the launching of space vehicles or the landing of aircraft. In this paper, a superelastic alloy, 60NiTi, is considered for rolling element bearing applications. A series of Rockwell and Brinell hardness, compressive strength, fatigue, and tribology tests have been conducted and are reported. The combination of high hardness, moderate elastic modulus, large recoverable strain, low density, and intrinsic corrosion immunity provides a path to the creation of bearings largely impervious to shock load damage. It is anticipated that bearings and components made from alloys with such attributes might alleviate many problems encountered in advanced aerospace applications.

    Keywords:

    materials, tribology, bearings, shock load resistance, mechanical components, superelastic materials


    Author Information:

    DellaCorte, Christopher
    National Aeronautics and Space Administration, Glenn Research Center, Cleveland, OH

    Noebe, Ronald D.
    National Aeronautics and Space Administration, Glenn Research Center, Cleveland, OH

    Stanford, Malcolm K.
    National Aeronautics and Space Administration, Glenn Research Center, Cleveland, OH

    Padula, Santo A.
    National Aeronautics and Space Administration, Glenn Research Center, Cleveland, OH


    Paper ID: STP103887

    Committee/Subcommittee: F34.01

    DOI: 10.1520/STP103887


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