Effect of microstructure on the dry sliding friction behavior of CoCrMo alloys used in metal-on-metal hip implants

• Published in: Journal of biomedical materials research. Part B, Applied biomaterials Vol. 76B; no. 2; pp. 281 - 286
• Main Authors: Varano, R., Bobyn, J. D., Medley, J. B., Yue, S.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.02.2006
• Subjects: Chromium Alloys - chemistry; CoCrMo; Friction; friction coefficient; Hip Prosthesis; Materials Testing; metal on metal; microstructure; Molybdenum - chemistry; Prosthesis Design; Stress, Mechanical; Surface Properties; X-Ray Diffraction
• ISSN: 1552-4973; 1552-4981
• DOI: 10.1002/jbm.b.30370

The microstructure and its effect on the friction behavior of a medical grade wrought cobalt–chromium–molybdenum (CoCrMo) alloy for surgical implants were studied in this work. In particular, the effects of compression and carbon (C) content on the above characteristics were analyzed. Increasing amounts of deformation resulted in a decrease in the number of annealing twins in the microstructures. In addition, there was an increase in the volume fraction of the hexagonal closed‐packed (HCP) phase due to a strain‐induced transformation (SIT) from the metastable face‐centered cubic (FCC) phase. The high C (HC) alloy had a lower volume fraction of this SIT phase. Friction studies conducted on these alloys revealed a higher coefficient of friction for the HC alloy and no significant effect of SIT on the friction characteristics. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006