STP796

    Tensile Strength, Fatigue Life, and Corrosion Behavior of Ti-318 and Ti-550

    Published: Jan 1983


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    Abstract

    Titanium alloy 318 (Ti-318) (Ti-6Al-4V) in both the annealed and solution-treated and aged conditions and titanium alloy 550 (Ti-550) (Ti-4Mo-4Al-2Sn) in the annealed condition were studied. Tension tests demonstrated that Ti-318 was little improved by heat treatment and that Ti-550 was slightly stronger than Ti-318. Corrosion fatigue tests were carried out in Ringer's solution at 50 Hz at a stress of 575 MPa using tapered cylindrical specimens with two surface finishes: (1) polished and (2) acid etched and shot peened. For Ti-318 the acid-etched, shot-peened condition reduced the scatter and revealed the slight superiority of the solution-treated and aged material. Forged material exhibited similar behavior to that of rolled material, and preliminary results suggested that Ti-550 was better than Ti-318 under any condition. Anodic polarization tests were carried out in deaerated buffered Ringer's solution at 37°C, with a pH of 7.4 and a sweep rate of 10 mV min−1. For passivated and steam-sterilized material there was little difference between Ti-318 and Ti-550. The effects of passivation and steam sterilization, anodization, and acid etch and shot peening were determined. It was concluded that, for joint replacement applications where high corrosion fatigue strength is required, solution-treated and aged Ti-318 offers a slight advantage over annealed Ti-318 and that Ti-550, on the basis of preliminary results, appears to offer an advantage over both.

    Keywords:

    titanium, mechanical properties, corrosion resistance, anodization, passivation, surface finish, implant materials


    Author Information:

    Dobbs, HS
    Lecturer and technician, The Institute of Orthopaedics, University of London, Brockley Hill, Stanmore, Middlesex

    Robertson, JLM
    Lecturer and technician, The Institute of Orthopaedics, University of London, Brockley Hill, Stanmore, Middlesex


    Paper ID: STP28946S

    Committee/Subcommittee: F04.12

    DOI: 10.1520/STP28946S


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