Binder jetting additive manufacturing of a 95W-3.5Ni-1.5Fe tungsten heavy alloy: Enhanced ductility and dynamic deformation mechanisms

This study demonstrates the fabrication of 95W-3.5Ni-1.5Fe tungsten heavy alloys (WHAs) via binder jetting 3D printing (BJ3DP) with optimized process parameters (layer thickness = 50 μm, binder saturation = 75 %) and a proprietary water-based binder formulation. After sequential processing—including printing, curing, debinding, and sintering—the alloy exhibited a characteristic two‐phase microstructure and achieved near‐full density (99.9 %). Compared with WHAs produced via conventional powder metallurgy, the BJ3DP‐fabricated alloy demonstrated markedly enhanced ductility while maintaining moderate yield and ultimate tensile strengths. Fractographic analysis revealed that improved interfacial bonding between tungsten particles and the γ-phase arises primarily from mechanisms of particle slip and crack bridging. Moreover, dynamic impact tests elucidated the strain-hardening behavior under varied loading conditions: at strain rates below 2000 s⁻¹, uniform plastic deformation via dislocation slip dominated, whereas at strain rates above 2000 s⁻¹, thermal activation promoted rapid dislocation rearrangement and annihilation within tungsten particles, leading to the formation of plate-like subgrains in the deformation zone. This dynamic recovery process effectively mitigates strain hardening and facilitates stress redistribution via localized shear deformation, thereby contributing to the alloy's superior ductility. These findings validate the effectiveness of the applied process-binder optimization strategy, providing critical insights into the deformation mechanisms of additively manufactured tungsten heavy alloys and offer a promising pathway for the design and optimization of high-performance materials for advanced engineering applications.