In situ TiB2 nanoparticles enable uniform electrochemical dissolution for enhanced dimensional precision and capillarity in additively manufactured micro inner channels (Φ 1.4 mm)

Electrochemical polishing (ECP) alone cannot overcome the limitations in inner surface roughness and dimensional accuracy imposed by heterogeneous dissolution behaviors in complex additively manufactured (AMed) parts, highlighting the need for material-based improvements. Here, we report a nanoparticle-enabled AMed alloy that intrinsically promotes uniform electrochemical dissolution. Using computed tomography (CT) slices analysis, in situ synchrotron X-ray imaging, and stimulation of the electrochemical dissolution process, we reveal that the improved uniform dissolution arises from grain refinement and corrosion crack deflection effects induced by in situ TiB₂ nanoparticles. The resulting increase in grain boundary density and reduction in grain size lead to a more randomized crystallographic orientation and a homogenized grain-related corrosion potential across the melt pool (MP). The decreased potential variation in depth, diffusion-controlled dissolution, coupled with enhanced lateral corrosion crack propagation, significantly improves dissolution uniformity in AMed TiB₂/AlSi10Mg. After ECP, the AMed TiB₂/AlSi10Mg heat pipes (Φ 1.4 mm) exhibit a reduction in inner surface roughness from 5.4 to 2.2 μm and in roundness tolerance from 59 to 31 μm, relative to the as-built AlSi10Mg counterpart. Moreover, a 218% increase in capillary action suggests enhanced heat transfer performance, supporting broader applications – specific performance and functionality in other complex AMed materials and structures.