Open Access

ABSTRACT

Influence of Subjection to SBF on Ultra-high Cycle Fatigue Behaviors of Ti-6Al-4V

LIU Yong-jie, TIAN Ren-hui, OUYANG Qiao-lin, WANG Qing-yuan

The International Conference on Computational & Experimental Engineering and Sciences 2011, 16(1), 5-6. https://doi.org/10.3970/icces.2011.016.005

Abstract

Ti-6Al-4V is widely used in biology engineering as well medical implant. Clinical investigations show that TC4 implant could have rupture of passivation film and visible corrosion. To predict service life of the Ti-6Al-4V implant, it is necessary to study its ultra-high cycle fatigue behaviors in physiological environment exceeding 10⁷ cycles. In this paper, using the ultrasonic fatigue testing technique, the high cycle and ultra-high cycle fatigue properties of Ti-6Al-4V subjection to simulated body fluid (SBF) in body temperature were studied and compared with that of normal Ti-6Al-4V. The experimental results show that SBF subjection has slight influence on the ultra-high cycle fatigue life of such material; the S-N curves descend continuously during 10⁴ and 10⁹ cycles and the descending tendency is lower in the region of 10⁷-10⁸ cycles; fracture can still occur beyond 10⁷ cycles showing there is no fatigue limit as the traditional fatigue conception describes. The observation of fracture surface investigated by scanning electron microscopy (SEM) and energy dispersive atomic X-ray (EDA X-ray) shows cracks mainly initiate from surface of specimen before the fatigue life of 10⁷ cycles and some specimens have multiple crack initiation sites; fatigue failure initiates from internal inclusion where mostly the element Al aggregates after the fatigue life of 10⁸ cycles.

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