Wear and cavitation erosion resistance of an ALMgSC alloy produced by DMLS

Pin-on-disk and cavitation tests were performed on an innovative Al-Mg alloy modified with Sc and Zr for additive manufacturing, which was tested in annealed condition. The damaging mechanisms were studied by observations of the morphology of the sample surface after progressive testing. These analyses allowed the identification of an adhesive wear mechanism in the first stages of pin-on-disk test, which evolved into a tribo-oxidative one due to the formation and fragmentation of an oxide layer with increasing testing distance. Regarding cavitation erosion, the AlMgSc alloy was characterized by an incubation period of approximately 1 h before mass loss was measured. Once material removal started, mass loss had a linear behavior as a function of exposure time. No preferential sites for erosion were identified, even though after some minutes of cavitation testing, the boundaries of melting pools can be seen. The comparison with literature data for AlSi10Mg alloy produced by additive manufacturing technology shows that AlMgSc alloy exhibits remarkable wear resistance, while the total mass loss after 8 h of cavitation testing is significantly higher than the value recorded for AlSi10Mg alloy in as-built condition.