Tribological behavior of AlSn20Cu alloy manufactured by additive friction stir deposition

Al-Sn alloy is utilized as a bearing material to replace conventional Sn-based alloy in the design of bearing liners due to its higher load-carrying capacity and wear resistance. However, cracks readily initiate in casting Al-Sn alloy near the coarse Sn phase, leading to low mechanical properties and insufficient wear resistance. The present study introduces a new method, additive friction stir deposition (AFSD), to produce AlSn20Cu alloy with fine grains and sub-micron-scale Sn phases, resulting in enhanced mechanical performance and wear resistance. Compared to both casting and cold rolling + annealing AlSn20Cu alloys, the ultimate tensile strength of AFSD AlSn20Cu alloy is improved by 80.56 % and 16.67 % respectively. Additionally, AFSD AlSn20Cu alloy demonstrates a lower coefficient of friction (COF) and lower wear rate without significant subsurface damage. This is attributed to the fine and uniformly distributed Sn phase forming a uniform and dense surface lubrication layer that adapts the friction pair to the boundary lubrication state, preventing the initiation and development of cracks. •AlSn20Cu alloy was produced by additive friction stir deposition (AFSD).••The AFSD alloy is characterized by fine grains and sub-micron-scale Sn phases.•The AFSD alloy exhibits outstanding mechanical performance and wear resistance compared to both casting and cold rolling + annealing alloys.•This is attributed to the fine and uniformly distributed Sn phase in AFSD alloy.•The fine Sn phase prevented the initiation and development of cracks.