Effects of powders and process parameters on density and hardness of A357 aluminum alloy fabricated by selective laser melting

Additive manufacturing processes based on the local fusion of a powder bed, such as selective laser melting (SLM), are a valid alternative to conventional technologies and a growing number of industrial sectors are currently relying on these processes for the production of different components. However, there are still some limits in using SLM and they are often related to the feedstock material. For this reason, in the present work, the effects of powder properties and pre-treatments, as well as process parameters, on the fabrication of aluminum alloy A357 samples were investigated. Two different batches of powder were considered in order to evaluate the effects of particles shape and size in the as-received condition and after two different pre-treatments: 60 °C for 3 h and 200 °C for 1 h. Selective laser-melted samples were produced in the conditions described above and were then characterized in terms of density, phase and chemical composition, defects, and hardness. The results showed a correlation between powder conditions in terms of morphology and pre-treatment on the properties of SLM A357 aluminum alloy components.