Processing of titanium-based materials from low cost titanium hydride powders: PIM and tape casting

This paper summarizes recent developments on titanium and titanium-nickel materials from titanium hydride powders. The feasibility of using this route to process performant, complex parts is assessed.

Feedstocks for PIM were prepared with binders composed of polyethylene, paraffin wax and stearic acid. Solvent debinding in heptane was followed by thermal debinding and dehydrogenation at 500°C under argon. Titanium parts were sintered at 1200°C under argon. The ultimate tensile strength (666 MPa) and elongation to fracture (15%) meet the requirements for titanium grade 4. Watch bracelet segments were injection molded, showing good shape preservation and reproducibility. Titanium-nickel alloys were sintered at 1200°C under hydrogen. Shape memory effects of more than 4% were measured. In addition, titanium-nickel parts with controlled porosity from 31 to 43% were sintered under argon at temperatures from 800°C to 1200°C.

Slurries for tape casting composed of powder, solvent, plasticizer and binder were used to produce green tapes, which were debinded and sintered to obtain porous titanium thin sheets with 25% porosity.