Aging Response of an A357 Al Alloy Processed by Selective Laser Melting

The A357 Al–Si–Mg alloy produced by selective laser melting is investigated in order to evaluate its response to thermal aging. Solution annealing followed by water quenching reveals responsible for the transformation of the interconnected Si network, typical of the as built material, into a dispersion of globular, and coarser constituent and for the formation of an equiaxed grain structure. The microstructural changes lead to a reduction of material hardness. DSC and aging curves show that as built condition can be considered as fully appropriate for an effective dispersion strengthening process by artificial aging. Natural aging reduces the amount of available sites for heterogeneous nucleation of β” phase and it is considered as detrimental for tensile properties.