Multi-Scale Mechanical Anisotropy and Heat Treatment Effects in Additively Manufactured AlSi10Mg

This study investigates the combined effects of build planes and heat treatments on the micro- and nanoscale mechanical properties of additively manufactured AlSi10Mg alloy. The hardness and elastic modulus were examined across two principal planes, XY and XZ, under three conditions: as-built (AB), after solution annealing followed by water quenching (SA), and artificially aged after solution annealing (SA&AA). The results reveal that hardness is significantly affected by heat treatment, decreasing after SA and partially recovering upon subsequent artificial aging (SA&AA), while remaining largely unaffected by build planes, with average values differing by less than 2%. In contrast, the elastic modulus demonstrates a clear anisotropy, correlated with the microstructural changes from both additive manufacturing and thermal post-processing. The XY plane initially shows a modulus up to 29% higher than the XZ plane. However, after aging, the values of both planes converge to similar levels. While average values suggest general trends, localized measurements reveal notable spatial heterogeneity in both the hardness and elastic modulus—particularly after thermal treatments—arising from microstructural evolutions. These findings highlight the complex interplay between orientation and thermal history, underscoring that the mechanical performance of AlSi10Mg is governed by the synergistic effects that influence anisotropy and local mechanical behavior.