Abstract: This patent describes metal flake composites consisting of metal flakes and thermoplastic resins as printing materials for additive manufacturing of prototypes with metallic appearance, improved mechanical properties and durability. Metal flakes of 5 to 50 microns in average size (D50) and 0.2-2 microns in thickness are made of base metals such as aluminum, chromium, cobalt, copper, iron, nickel, tin, titanium, zinc, and their alloys, e.g., stainless steel, brass and bronze by ball milling metal powder precursors in the presence of a liquid solvent and lubricants. Thermoplastic resins such as Nylon, polystyrene, polycarbonate, acrylonitrile butadiene styrene are coated with metal flakes in a composition ranging from 0.5 to 50% by weight. The composite undergoes a bonding process to improve its adhesion and uniformity.