Preparation of powder from Ti-6Al-4V chips by self-propagating high-temperature synthesis hydrogenation and thermal dehydrogenation

Abstract

The paper proposes a novel method for processing Ti-6Al-4V titanium chips into fine powder using self-propagating high-temperature synthesis (SHS)-hydrogenation technology and subsequent thermal dehydrogenation. It was found that SHS-hydrogenation leads to the formation of single-phase titanium hydride with a cubic crystal lattice. Subsequent grinding of the brittle hydrogenated chips in a ball mill produced a powder with a particle size of 10–40 μm and an angular shape. Thermal dehydrogenation in vacuum resulted in a powder with equilibrium fine (α + β) structure (grain length 2–3 μm, thickness ≤1 μm) and residual hydrogen content of 0.015 wt.%. The effectiveness of the developed methodology is demonstrated by the ability to produce powders with minimal impurity content and a controlled microstructure, thus providing an effective solution to the problem of recycling titanium waste. The results of the work are of practical interest for additive manufacturing and powder metallurgy of titanium.