On November 1, 2026, the journal Materialia published a study titled "Hierarchical phase formation in tungsten heavy alloys fabricated via laser powder bed fusion," which systematically revealed the non-equilibrium solidification microstructural characteristics of 90W-7Ni-3Fe tungsten heavy alloy fabricated by laser powder bed fusion (LPBF) using multiscale characterization methods. SEM imaging showed position-dependent thermal gradient variations during the LPBF process. EBSD analysis indicated that the alloy exhibits a randomly oriented equiaxed grain structure with no preferred texture, an average grain size of approximately 10.75 μm, and an average geometrically necessary dislocation density of 3.06×10¹³ m⁻². Submicron γ precipitates and nanopores of approximately 100 nm were observed within W grains. Selected area electron diffraction confirmed the orientation relationship [011]W∥[001]γ between BCC W and FCC γ phases. TEM directly observed, for the first time, high-density dislocation pile-ups in LPBF tungsten heavy alloy and revealed nanoscale Fe₂W Laves phase precipitates in some matrix regions that had not been previously reported in conventional powder metallurgy processes. Although Fe₂W is generally regarded as a brittle phase, its presence as nanoscale precipitates is expected to strengthen the tungsten alloy through the Orowan mechanism. Tungsten heavy alloy (WHA) is a dual-phase composite composed of tungsten with elements such as nickel and iron, and is widely used in aircraft engine flywheels, rotors, counterweights, medical radiation shielding, and plasma-facing components of fusion reactors. Conventional powder metallurgy processes such as liquid-phase sintering are mature, while additive manufacturing has become an emerging alternative route owing to its near-net-shape capability for complex components. This study lays the foundation for establishing process–microstructure–property relationships for AM tungsten heavy alloys and for promoting microstructure-driven design.