Sliding wear performances of 316 L, Ti6Al4V, and CoCrMo alloys

In this study, tribological performances of three alloys, 316 L, Ti6Al4V, and CoCrMo, used in manufacturing orthopedic implants, are compared. Wear tests were conducted on a reciprocating wear tester by rubbing an Al2O3 ball. It was found that the wear resistance of the 316 L and CoCrMo alloy was almost 2 and 24 times of the Ti6Al4V alloy, respectively, whose steady state friction coefficient lies between those of the 316 L and CoCrMo alloy. Examinations of wear tracks and contact surfaces of the Al2O3 ball revealed the dominant wear mechanisms as abrasive for CoCrMo and adhesive for 316 L and Ti6Al4V alloy. These observations confirmed that the favorably biocompatible characteristics of Ti6Al4V alloy was not accompanied by a reasonable sliding contact performance. In this respect, surface modification is a necessity for load bearing Ti6Al4V implants to extend their durability in the human body to the levels of 316 L and/or CoCrMo implants. K e y w o r d s: CoCrMo, 316 L, Ti6Al4V, wear