Influence of Silicon and Magnesium on the Mechanical Properties of Additive Manufactured Cu-Al Alloy

By using cold metal transfer technique, Cu-Al alloy with addition of silicon (Si) and magnesium (Mg), viz (1) Cu-6.5% Al and (2) Cu-6.5% Al-1.2% Si-0.5% Mg were manufactured additively. Four samples were deposited: Cu-6.5% Al alloy as samples 1 and 2, and Cu-6.5% Al-1.2% Si-0.5% Mg alloy as samples 3 and 4. The alloys were homogenized by heat treatments: (1) 800°C (2 h) for sample 2 and (2) sample 4, to improve their mechanical properties. Detailed microstructural investigation conducted using scanning and transmission electron microscopies showed formation of various intermetallic phases. Results revealed that (1) the addition of Si and Mg increases the strength properties and ductility and (2) heat treatments improved strength properties but reduce the ductility of the alloys. The article discusses the correlation of the identified microstructure and the evaluated mechanical properties of the additively manufactured alloys.