Fatigue and wear properties of Ti-6Al-4V alloy with Cr/CrN multilayer coating

In this study, Cr/CrN multilayer coatings with different number of bilayers were deposited on Ti-6Al-4V alloy substrates by an arc ion plating method. Tension-tension fatigue tests and pin-on-disk wear tests were performed in order to examine the influence of the number of Cr/CrN bilayers on the fatigue and wear properties. The hardness increased with increasing number of Cr/CrN bilayers according to the Hall-Petch equation; however, the magnitude of the increase was minimal. Fatigue strength was improved by the multilayer coatings compared with CrN single layer coatings; in particular multilayer coatings with 3-5 bilayers showed higher fatigue strength. In contrast, in the wear tests, multilayer coatings with 4 or 5 bilayers showed severe wear damage while multilayer coatings with 3 bilayers showed good wear resistance. Thus, multilayer coatings with 3 bilayers were shown to improve both wear and fatigue resistance.