Dehydrogenation debinding process of MIM titanium alloys by TiH₂ powder

Abstract

A novel route was investigated for the preparation of metal injection moulding (MIM) titanium alloys by TiH₂ powder. It can be known from the analysis of thermodynamics and kinetics of dehydrogenation reaction that decomposition occurs when hydrogen partial pressure is ∼10⁻² Pa at 300^°C. The temperature range of dehydrogenation is within that of debinding so that the dehydrogenation and debinding can be carried out simultaneously. The hydrogen content of the sample debound in 10⁻² Pa is merely 0·016 wt-% as the temperature raised up to 525^°C, indicating that the hydrogen can be removed effectively. Finally, the sintered parts with average tensile strength of 770 MPa and specific elongation of 4·3% were prepared, of which the impurity contents were satisfactory. The sintered parts have the uniform fully lamellar microstructure, in which the interlamellar spacing between α phases is thin.

Keywords:

• DEHYDROGENATION
• DEBINDING
• METAL INJECTION MOULDING
• TITANIUM ALLOYS
• TIH2 POWDER