Tribological behavior in Cu-10Sn alloy fabricated by laser powder bed fusion under oil lubrication

• Quantitative evaluation of tribological properties: the wear rate at 70°C and 200°C exhibits a non-monotonic dependence on normal loads from 50N to 200 N, initially decreasing before increasing sharply, with a minimum consistently observed at 150 N. • Formation mechanism insights: the formation of the tribolayer is driven by severe plastic deformation, dynamic recrystallization, and grain refinement under localized stress concentration. • Tribological behavior insights: the removal rate of the oxide layer surpasses its growth rate, causing the formation of a loose, multi-layered structure and a transition to severe delamination wear. • Implications for practical use: offers comprehensive understanding and valuable insights for the critical role of the tribolayer evolution in controlling the wear mechanism of LPBF-fabricated Cu-10Sn alloy under oil lubrication. Cu-10Sn alloys are used in transmission components for their load-bearing and anti-friction properties. The oil-lubricated tribological behavior of laser powder bed fusion (LPBF)-fabricated Cu-10Sn alloy was investigated under loads of 50–200 N at 70°C and 200°C. At both 70°C and 200°C, the wear rate first decreased and then increased with increasing normal load, reaching a minimum at 150 N. The wear rate at 200°C is 2.53 × 10 -6 –6.88 × 10 -6 mm 3 /(N·m), lower than 5.44 × 10 -6 –11.49 × 10 -6 mm 3 /(N·m) at 70°C, revealing superior wear resistance at high temperatures. A complex tribolayer forms at the sliding interface, consisting of an oxide layer (OL), a mechanically mixed layer (MML) and a plastically deformed layer (PDL), which is governed by a dynamic oxidation‑scrape‑reoxidation mechanism. At a moderate load, the synergy between fluid lubrication from the oil film and solid lubrication provided by the tribolayer contributes to the excellent tribological performance of the alloy. However, under an excessive load, the removal rate of the OL surpasses its growth rate, resulting in a transition from mild oxidative wear to severe delamination wear. These findings provide critical insights into the wear mechanisms of LPBF-fabricated Cu-10Sn alloys under service conditions.