Microstructure and Mechanical Properties of Al-(12-20)Si Bi-Material Fabricated by Selective Laser Melting.

In this study, a combination of Al-12Si and Al-20Si (Al-(12-20)Si) alloys was fabricated by selective laser melting (SLM) as a result of increased component requirements such as geometrical complexity and high dimensional accuracy. The microstructure and mechanical properties of the SLM Al-(12-20)Si in as-produced as well as in heat-treated conditions were investigated. The Al-(12-20)Si interface was in the as-built condition and it gradually became blurry until it disappeared after heat treatment at 673 K for 6 h. This Al-(12-20)Si bi-material displayed excellent mechanical properties. The hardness of the Al-20Si alloy side was significantly higher than that of the Al-12Si alloy side and the disparity between both sides gradually decreased and tended to be consistent after heat treatment at 673 K for 6 h. The tensile strength and elongation of the Al-(12-20Si) bi-material lies in between the Al-12Si and Al-20Si alloys and fracture occurs in the Al-20Si side. The present results provide new insights into the fabrication of bi-materials using SLM.