Producing multilayer laminated composite of aluminium/copper by friction stir additive manufacturing process

The objective of this study was to assess the feasibility of producing Al-Cu multi-layered composite through the friction stir additive manufacturing (FSAM) process and to analyse the microstructure and mechanical properties of the fabricated composite. The composite was fabricated at a rotational speed of 1100 rpm, traverse speed of 60 mm/min and a 2° tilt angle. The macrostructure, microstructure, and intermetallic formation were observed and analysed. The macro and microstructure results indicated that achieving defect-free build is feasible in the selected parameter settings. In-depth examinations using energy-dispersive x-ray spectroscopy (EDS) and x-ray diffraction (XRD) unveiled the presence of intermetallic compounds (IMCs) such as AlCu, Al2Cu, and Al4Cu9 within the stir zone in various regions of the build. Notably, inhomogeneous microhardness levels ranging from 56.7 HV0.1 and 324.6 HV0.1 were noted, corresponding to distinct microstructural features and the various IMCs within the build. The Al-Cu composite demonstrated an excellent balance of strength and ductility, with an ultimate tensile strength of 187.7 MPa and an elongation of 19%. These findings bring out the exceptional opportunity presented by FSAM process for fabricating innovative Al-Cu multilayered composites with unique mechanical properties.