A new insight on induced-tribological behaviour of hypereutectic Al-Si alloys manufactured by selective laser melting

In this work, the tribological behaviour of selective laser melting (SLM) processed hypereutectic Al-Si alloy is investigated by the ball on disc test with focus on the effect of silicon content (18 and 50 wt %). Different from the conventional casted sample, the SLM processed sample shows an ultra-fine microstructure with silicon size inferior to 5 μm. Indeed, the SLM processed hypereutectic Al-Si alloy illustrates a pseudo-eutectic microstructure consisted by supersaturated Al(Si) and primary silicon. Both the SLM processed Al-18Si and Al-50Si presents low wear rate about of 7.0 and 8.1◊10−4 mm3/(N◊m) respectively. Moreover, the wear mechanisms of conventional casted and SLM processed hypereutectic Al-Si alloys are compared and discussed. [Display omitted] •SLM processed hypereutectic Al-Si illustrates a pseudo-eutectic microstructure.•As Si content increases, the size of primary Si in pseudo eutectic structure increases.•SLM processed sample shows higher wear resistance than that of conventional casted.•A (crushing)-inlaying-abrasive wear mechanism was proposed for SLM processed Al-Si.