Insights on the Tribological Characteristics of Titanium Alloys in Demanding Environments

Titanium alloys are widely used in demanding applications due to their exceptional strength-to-weight ratio, high-temperature resilience, and excellent corrosion resistance. Understanding their tribological behavior is critical, as the performance and durability of several mechanical systems, particularly in gas turbine engines, are often constrained by friction and wear in complex contacting and mobile assemblies. This study investigates the tribological behavior of two widely used titanium alloys, Ti-6-4 and Ti-6-2-4-2, focusing on their interfacial phenomena under varied operational conditions. Tribological testing was conducted using a reciprocating tribometer at different temperatures and loading conditions. Ex situ analyses revealed that wear mechanisms were heavily influenced by the properties of the oxide layer formed during sliding. Under higher loads, the oxide layer on the alloy surface fractured, resulting in the generation of flake-like debris, which contributed to third-body abrasion. Additionally, the study examined the transfer film formation on the alumina counterface under various conditions, correlating friction, and wear behavior with interfacial processes, particularly the oxide formation on the worn surfaces. This study enhances the understanding of the tribological behavior of titanium alloys, paving the way for improved performance in demanding applications through advanced surface modification techniques. © 2024 by ASME.