| Abstract Scope |
Extrusion-based additive manufacturing enables the fabrication of complex W-Ni-Fe parts, yet the final density and microstructure are largely determined by liquid-phase sintering and its dependence on alloy composition, which remains insufficiently understood. This work compares two printed alloys, 90W-7Ni-3Fe and 93W-4.6Ni-2.4Fe, to clarify how chemistry affects sintering behavior. A combined CALPHAD-based and kinetics-informed framework was used to analyze liquid formation, W solubility difference between phases, and Fe redistribution during thermal processing. The results show clear composition-related differences in liquid evolution, γ-phase chemistry, and elemental partitioning. XRD confirms that both alloys remain primarily composed of W and γ phases after sintering. Comparative SEM/EDS reveals distinct redistribution behavior in the two alloys, whereas TEM observations in the 93W alloy further identify nanoscale W/γ coexistence and heterogeneous interfacial strain. A composition-process map for 88-95 wt.% W is further proposed to support alloy and sintering design. |