Polylactic acid as biobased binder for the production of 3D printing filaments for Ti6Al4V alloy manufacturing via bound metal deposition

Abstract

In this paper, a biobased binder mainly composed of polylactic acid (PLA) was developed for the production of Ti6Al4V feedstock suitable for 3D printing via material extrusion. 3D printed samples were debound via solvent and thermal treatments and successfully sintered in reducing atmosphere obtaining dense metallic components. The designed and produced bio-binder is completely eliminated during the debinding processes leading to sintered samples showing a high densification (93–94%), with a microstructure composed of primary alpha phase with segregated beta phase at grain boundaries and having average grain size of 70 μm. 3D printed sintered samples show good mechanical properties (yield strength (σy) = 662 MPa, ultimate tensilte strength (UTS) = 743 MPa, elongation at break (εmax) = 12%, hardness = 5.15 GPa) influenced by the sintering parameters and the presence of some degree of micro-porosity in the final structure.

Keywords

• Polylactic acid
• Biobased binder
• Titanium alloy
• Bound metal deposition
• Additive manufacturing
• Debinding and sintering