Mechanically strong, stiff, and yet ductile AlSi7Mg/graphene composites by laser metal deposition additive manufacturing

Abstract Laser metal deposition (LMD) with a coaxial powder feeding technology has been applied to fabricate pure aluminum alloy (AlSi7Mg) and low oxidation graphene aluminum matrix (LOG-Al) composites with low oxidation graphene (LOG) contents of 0.05 wt % and 0.1 wt % after the powder was prepared by wet ball milling. The LOG-Al composites showed improvements in all properties including hardness, tensile strength, ductility, modulus of elasticity and yield strength with the increase of LOG addition contents. The microstructures and fracture surfaces of the composites were observed and the results of TEM, HRTEM, optical microscope, EBSD, XRD spectra, Raman spectra, Vickers hardness, tensile properties were analyzed. The effects of wet ball milling, the addition of low oxidation graphene and its contents and LMD process on microstructure formation and resulting mechanical properties were discussed.