Thermal Treatments of AlSi10Mg Processed by Laser Beam Melting

Recent studies have shown that AlSi10Mg processed by Laser Beam Melting (LBM)
exhibits a much finer microstructure when compared to its cast counterpart as a consequence of
the much faster cooling rates imposed in the LBM process. Such microstructural refinement
causes a significant increase in strength and hardness, to such an extent that as-fabricated LBM
AlSi10Mg was reported to present hardness value of 127 ± 3 Hv0.5, similar to the hardness of
high pressure die cast AlSi10Mg in the aged condition (i.e. 130-133 Hv). Yet, little attention has
been given so far to the influence of thermal treatments on the microstructure and mechanical
behavior of LBM AlSi10Mg. The present work hence aims to investigate the effect of two
different types of heat treatments – i.e. (i) stress relief and (ii) solutionizing and ageing − on the
microstructure, hardness and tensile properties of LBM AlSi10Mg.