Researchers at Yale University have just demonstrated a new means of 3D printing metal using metallic glass filaments. The technology provides a means of producing metal through processes similar to extrusion. Despite being metal, BMGs (bulk metallic glasses) become far softer upon heating, allowing for easier deposition, similar to that of thermoplastics.
Since BMGs have a super-cooled liquid region in their thermodynamic profile, they can achieve such a state. Harnessing these characteristics, the researchers generate solid, high-strength metal components in conditions similar to those of FFF/FDM. Much like traditional thermoplastics, these materials exhibit high strength and elastic limits.
“We have shown theoretically in this work that we can use a range of other bulk metallic glasses and are working on making the process more practical- and commercially-usable to make 3D printing of metals as easy and practical as the 3D printing of thermoplastics,” said Prof. Jan Schroers, who was also working with Desktop Metal for this project.
Benefits of Metallic Glass Filaments
The metallic glass filament rods also exhibit high fracture toughness and high corrosion resistance. This makes them ideal for industrial production in the aerospace or medical fields. The researchers tested metallic glass filaments consisting of zirconium, titanium, copper, nickel and beryllium. This alloy formula (Zr44Ti11Cu10Ni10Be25) is quite a common BMG.
The team employed amorphous rods measuring 1 mm in diameter and 700mm in length. The extrusion temperate was 460 °C with an extrusion force of 10 to 1,000 Newtons to mold the softened fibers and press them through a 0.5mm diameter nozzle. The fibers are then ready to extrude into a 400°C stainless steel mesh where crystallization delays until for the period of a whole day has, after which a robotically controlled extrusion process creates the desired object.
Prof. Schroers added, “In order to widely use BMG 3D printing, practical BMG feedstock available for a broad range of BMGs has to be made available. To use the fused filament fabrication commercially, layer-to-layer bonding has to be more reliable and consistent.”
Featured image courtesy of the study’s authors. A study excerpt can be found here, via Elsevier.