The effect of temperature rise on the wear mechanisms of 3D-printed TC4 alloy under different loads and ambient temperatures

This work investigates the role of friction-induced temperature rise in governing wear mechanisms of Ti-6Al-4 V alloys (TC4) manufactured by Direct Metal Laser Sintering (DMLS). Reciprocating sliding wear tests were performed under a wide temperature (25–400 °C) as well as load (5–60 N) range. The temperatures at the measurement points were monitored in real time using embedded K-type thermocouples. The coefficient of friction (COF) displays a non-monotonic trend under constant applied load, initially increasing and subsequently decreasing with rising environmental temperature. Compared to loads of 5–20 N, this COF transition occurs at lower temperatures under 40–60 N loads, a shift attributable to the higher frictional heating at the specimen surface under these heavier loads. Elevated temperature combined with high load (60 N, 400 °C) promotes the formation of a protective tribo-oxidative layer on the specimen surface, leading to a significantly reduced wear rate relative to ambient conditions. Microscopic analysis of worn surfaces elucidates the evolution of the dominant wear mechanism. These findings reveal that the wear mechanism of TC4 progressively shifts from abrasive wear to adhesive wear and oxidative wear as environmental temperature and applied load increase.