A COMPARISON OF THE MECHANICAL-BEHAVIOR OF ALUMINAS IN AIR AND SIMULATED BODY ENVIRONMENTS

Fracture toughness and modulus of rupture tests have been carried out on three aluminas, which differed in composition and microstructure, in a variety of environments (air, deionized water, albumen/salt solution, Ringer' s solution, and fresh human plasma). Generally tests in liquid environments were found to result in a reduction in the as-measured critical stress intensity factor and the modulus of rupture, as compared with the values appertaining to air. However, estimates of the stress for a 50-year, 99. 9% survival probability were encouraging; for high-purity, small-grain-size alumina a value of 112 MN/m**2 was created, which is considerably greater than the estimated maximum tensile stress in a femoral sphere.