| Abstract Scope |
Interstitial hydrogen can be used to convert Ti-6Al-4V machining scrap into powder by promoting hydride-assisted embrittlement at room temperature. This study examines how machining-induced microstructures in thin and thick Ti-6Al-4V chips control hydrogen diffusion, trapping, TiH₂ formation, and fragmentation during reactive ball milling in oxygen-free, hydrogen-bearing atmospheres. Thin and thick chips are compared because their deformation strain rate, shear band morphology, α/β interface distribution, and dislocation density may produce different hydrogen uptake and comminution responses. In Ti-6Al-4V, β phase regions provide rapid hydrogen transport pathways, so α/β interfaces, dislocations, and shear band regions are expected to act as preferred trapping and hydride nucleation sites. Hydrogen uptake is monitored using an instrumented milling system. SEM, XRD, TEM, and LIBS are used to correlate chip microstructure, powder morphology, α/β interface characteristics, hydride formation, and oxygen content. This work clarifies how interstitial hydrogen effects can be leveraged for energy-efficient titanium alloy powder production. |