Effect of Powder Characteristic and Aging Treatment on the Corrosion Behavior of Selective Laser Melted Al-20Si Alloy

Hypereutectic Al-20Si alloy is widely used in automotive, aerospace, and other fields because of its lightweight, high thermal conductivity, good wear, and corrosion resistance. In this study, the effects of powder characteristics and aging treatment on the corrosion behavior of Al-20Si alloy prepared by selective laser melting (SLM) were systematically investigated. The results showed that the Al-20Si alloy synthesized with ball-milled powders (BMPs) presents a large number of pores and coarse Si particles, while the Al-20Si alloy prepared with atomized powders (APs) shows a uniform and dense microstructure with relatively small grain sizes. The Si phase was continuously precipitated and coarsened with increased aging temperature. Moreover, the fibrous eutectic Si prepared with APs was transformed to a particulate shape. The alloy manufactured with APs shows excellent corrosion resistance. Meanwhile, with the increase of aging treatment temperature, the corrosion resistance of the alloy was significantly reduced.