Fabrication of Fe-based amorphous alloy green sample using innovative wax-based material extrusion fused deposition modelling

Purpose This study aims to investigate a non-fusion, material extrusion additive manufacturing (AM) route for the fabrication of Fe-based metallic glass green parts, aiming to reduce the thermal risks associated with fusion-based AM. This was achieved using a novel ternary wax-based binder system designed for the low-pressure extrusion of amorphous powders. Design/methodology/approach A screw-driven fused deposition modelling (FDM) system was used to process a 90:10 Wt.% powder-binder feedstock. The wax-based binder consisted of 50% paraffin, 25% coconut and 25% soy wax. Rheological characterisation was performed to assess the flow behaviour. A Taguchi L9 orthogonal array was used to evaluate the influence of the material extrusion rate (MER), print speed and layer height on the printed part density, porosity and surface roughness (Ra). Findings The results of this study demonstrate stable and continuous extrusion of the feedstock. Within the current Taguchi analysis, MER showed the strongest effect on the measured density and porosity responses. A lower MER (0.12 g/min) minimised viscoelastic flow instability and air entrapment in the study. Conversely, layer height was the predominant factor for surface topography, contributing 57% to the variance in Ra, with an optimal parameter threshold of 0.50 mm. Originality/value This study proposes a preliminary pathway for producing Fe-based metallic glass green parts using a ternary wax-based material extrusion route. Further debinding, sintering and mechanical validation are required before final component-level manufacturing can be claimed.