Precipitate formation in cerium-modified additively manufactured AlSi10Mg alloy

AlSi10Mg alloy modified with 4 wt.% cerium was fabricated by selective laser melting and subjected to a T6 solutionizing (2 h at 535 degrees C) and ageing (10 h at 160 degrees C) heat treatment. Microstructure, precipitates and hardness of as-built and heat-treated samples were analysed. Results show that as-built samples contained a refined cellular-dendritic microstructure as well as Ce-containing precipitates at heat-affected zone (HAZ). After T6 heat treatment, cellular-dendritic microstructure converted to fine microstructure containing Si agglomerates and submicron Ce-containing precipitates, while precipitates present in as-built HAZ underwent spheroidisation. Hardness testing showed that addition of Ce did not affect alloy hardness. However, the fine dispersion of Ce-containing precipitates and good coarsening resistance shows that Ce is a promising alloying element for the development of heat-resistant alloys.