Mixed‐Scale Powder Enables 3D Printing of Tungsten Alloy

ABSTRACT

Laser powder bed fusion (LPBF) offers a promising route for manufacturing tungsten alloy components with complex geometries, whereas W–Ni–Fe alloys remain the most widely used tungsten alloys because of their excellent overall performance. Using nano‐sized Ni–Fe particles can further promote the densification and strengthening of LPBF‐fabricated W–Ni–Fe parts. However, nano‐enabled W–Ni–Fe powders face a critical trade‐off between reinforcing‐phase content and powder‐bed quality of LPBF: although a higher Ni–Fe content is generally beneficial for performance enhancement, excessive nanoparticles tend to deteriorate powder flowability and thereby impair powder‐bed uniformity during LPBF. Here, we propose a mixed‐scale nano/micron Ni–Fe/W powder design to overcome this dilemma and enable the fabrication of fine‐grained, high‐quality W–Ni–Fe parts by LPBF, thereby providing an alternative mixed‐scale strategy for reinforcing‐phase design. Compared with conventional mono‐scale nano Ni–Fe/W powder, the mixed‐scale powder promotes pronounced grain refinement, resulting in an average grain size of 4.90 μm. Meanwhile, it significantly improves both the forming quality and mechanical performance, achieving a surface roughness ( S _a ) of 7.56 μm, a compressive strength of 2534.2 MPa, and a compressive strain of 34.1%. This work provides an engineering‐feasible powder design strategy and processing pathway for the LPBF fabrication of high‐performance tungsten alloys, and may also be extended to the additive manufacturing of other refractory metals that face a similar trade‐off between reinforcement content and powder flowability.