Ti6Al4V alloy fabricated by gelcasting based on low-oxygen gel system using hydride-dehydride titanium alloy powders

Oxygen and carbon impurity residues and low density are the main issues for Ti gelcasting. To overcome these difficulties, this study develops a low-oxygen isoprene (Ip)/polyvinyl butyral (PVB) gel system to achieve Ti gelcasting using hydride-dihydride (HDH) Ti6Al4V powder. Slurries with 48 vol% solid loading content are employed to achieve moulding followed by cold isostatic pressing. During gelcasting, powder particles are held in place by the cross-linking of Ip monomer with PVB as adhesive to maintain shape. After sintering, nearly fully dense (4.38 g/cm3) Ti6Al4V alloys with low interstitial contamination (O: 0.356 wt%, C: 0.14 wt%) are successfully fabricated. The samples exhibit acceptable mechanical performance, with ultimate tensile strength of 1062 MPa, yield strength of 987 MPa, and elongation of 8.75%. Typical plastic fracture with river patterns is observed, which is distinctly different from that of HEMA based sample.