Sustainable upcycling of coarse TA15 powder waste into high-performance TiB-whisker-reinforced composite powders

Addressing the pressing issue of coarse TA15 titanium powder waste (>150 μm) accumulation in additive manufacturing, this study introduces a high-value upcycling strategy using the plasma rotating electrode process (PREP) to fabricate TiB/TA15 pre-alloyed composite powders. A quantitative cooling model reveals the cooling rate increases from 5.39 × 10⁴ to 5.13 × 10⁶ K/s as particle size decreases. This rapid cooling, combined with the pinning effect of in-situ TiB whiskers, induces pronounced microstructural changes: α′ martensitic laths are refined from 1.162 μm to 0.528 μm, and TiB reinforcements transform from a continuous network to a dispersed distribution. The TiB whiskers within the composite powders are characterized by a high density of intrinsic stacking faults and retain clean, well-bonded interfaces with the matrix. This reinforcement phase not only enhances the intrinsic strength of the composite powders but also effectively inhibits matrix prior-β grain coarsening. This work provides a cost-effective and scalable pathway for converting titanium waste into high-quality feedstock for advanced composite manufacturing.