Sliding Wear Behavior of Ti-6Al-1.5V-1Mo-0.5Zr-0.1C Alloy Modified with Small Additions of Ru and Different V and Mo Contents.

Titanium alloys have been successfully used in the energy industry due to their stability at high temperature service, good mechanical properties and corrosion resistance. The near-α Ti-6%Al-1.5%V-1.0%Mo-0.5%Zr-0.1%C alloy, has been successfully used in several parts for geothermal energy generation. Several studies have concluded that the wear behavior of Ti alloys is generally poor; however, the specific tribosystem must be analyzed. This work analyzes the additions of 0.3%Ru, and variations of the V and Mo contents on the wear performance of a Ti alloy. Different combinations of α+β and degrees of microstructural refinement were observed depending on the composition. Wear test were undertaken by using a dry sliding block-on-ring configuration under the ASTM G77 standard. Two different loads (7 and 25 N) were used against a M2 hardened steel ring as a counter face with a hardness of 790 HV. Results showed that for the 7N load, the wear behavior is related to the volume fraction and thickness of the α phase; on the other hand, for the 25N load tests, the wear losses are directly proportional to the bulk hardness of the alloys and the α plate thickness, for this condition, best wear performance was achieved by the alloy 3 which contains 1.0wt%V, 1.8wt% Mo and 0.25wt% Ru. From the experimental results of the present study, it has been found that the wear behavior is directly related to the microstructure, e.g. amount of phases, refinement degree, applied load, and, in a lesser extent to the bulk hardness.