Anti-corrosion and wear resistance properties of AlSi10Mg alloy and SiC/AlSi10Mg composites fabricated by selective laser melting

The SiC/AlSi10Mg composites were fabricated via selective laser melting（SLM）. The phase characteristics， microstructure， anti-corrosion and wear resistance properties of SLM SiC/AlSi10Mg and SLM AlSi10Mg samples were investigated by XRD， SEM， EDS， EBSD， electrochemical test， and friction and wear test. The results show that in the 3.5% （mass fraction） NaCl solution， the corrosion current density of SLM SiC/AlSi10Mg （2.0827 μA/cm2） is lower than that of SLM AlSi10Mg （3.389 μA/cm2）， and the passivation film on the surface of SLM SiC/AlSi10Mg （7.1 nm） is thicker than that of SLM AlSi10Mg （1.9 nm）， indicating the SLM SiC/AlSi10Mg sample has better corrosion resistance than that of SLM AlSi10Mg. The reason can be attributed to that the addition of SiC causes the grain refinement， the increase of high grain boundary， and the interruption of the continuity of Al matrix， leading to the decrease of corrosion rate and the increase of corrosion resistance. In addition， the average microhardness for SLM SiC/AlSi10Mg composites （207.68±16.02）HV0.2 is twice that of SLM AlSi10Mg alloy （103.58±7.41）HV0.2， indicating its hardness and wear resistance are improved. Both the wear mechanisms of SLM AlSi10Mg and SiC/AlSi10Mg composites are mainly abrasive wear and oxidation wear.