Dry sliding behavior of AlSi10Mg alloy produced by Laser-based Powder Bed Fusion: influence of heat treatment and microstructure

The L-PBF AlSi10Mg alloy is widely used in the production of structural parts in the transportation sector. However, the high stresses caused by the severe operating conditions require an optimal combination of mechanical and tribological properties. This paper reports on the effect of optimized T5 heat treatment (direct artificial aging: 4 h at 160 °C) and novel T6 heat treatment (rapid solution: 10 min at 510 °C, followed by artificial aging: 6 h at 160 °C) on the tribological behavior of the L-PBF AlSi10Mg alloy. Dry sliding tests (ball-on-disk) were carried out using AlSi10Mg samples as rotating disks against an Al2O3 stationary ball. The optimized T5 led to the formation of a stable protective oxide layer well adherent on the worn surface, increasing the wear resistance of the alloy. In addition, the novel T6 improved wear resistance compared to conventional T6 due to microstructural refinement induced by shorter solutionizing. The sub-surface analysis of the wear tracks highlighted the higher cohesion between the more homogeneous and finer Si particles and the α-Al matrix, as well as the improved load-bearing support compared to the coarser microstructure induced by conventional T6. Therefore, the new T6 could be the optimal solution for high-performance components.