EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The present work focuses on the fabrication and characterization of hard anodizing (HA) and plasma electrolytic oxidation (PEO) coatings on an Al10Si1Mg alloy manufactured via direct metal laser sintering (DMLS). The coatings were fabricated on both XY and XZ directions of the DMLS alloy. A A361 cast alloy was also treated for comparison. The hardness (H) and elastic modulus (E) of the coatings was measured by nanoindentation and the wear resistance was evaluated via reciprocating sliding tests.
The DMLS alloy presented microstructural anisotropy in the XY and XZ planes according to the direction of the Melt Pools (MP) formed along the laser path. The microstructure within the MP consisted on α-Al cells embedded in a fine 3D Si-network, which became coarser at the MPBs. HA and PEO coatings fabricated on both XY and XZ direction of the AM alloy were found to be more homogeneous in terms of morphology, thickness and composition than the coatings on the cast alloy. Crystalline SiO2 was formed in both HA and PEO coatings on the AM alloy probably due to the fine homogeneous distribution of Si. The estimated wear rates (Wr) were 1 and 2 orders of magnitude lower than the ones of the bare substrates for the HA and PEO coatings, respectively. On the other hand, AM-coated samples presented higher Wr than the A361-coated samples, as well as having certain mechanical anisotropy.
These results indicated that the fine 3D Si-network might compromise the mechanical response of the coatings fabricated via HA and PEO on the AM Al10Si1Mg alloy.