Development of porous Ti6Al4V samples by microsphere sintering

• Published in: Journal of materials processing technology 2012-01, Vol.212 (1), p.3-7
• Main Authors: Reig, Lucía, Amigó, Vicente, Busquets, David J., Calero, Jose A.
• Format: Article
• Language: English
• Subjects: Bending strength; Bones; Materials selection; Metallic implant; Microsphere sintering; Microspheres; Molds; Moulds; Porous titanium; Sintering (powder metallurgy); Stiffness; Stoneware; Zirconium dioxide
• ISSN: 0924-0136
• DOI: 10.1016/j.jmatprotec.2011.06.026

Titanium stiffness remains too high when compared to that of cortical human bones, which leads to a loosening of the implant. In the present work, titanium stiffness has been reduced by developing a porous network by microsphere sintering. Machining the porous specimens obtained is very complex as microspheres tend to detach during grinding. Thus, selecting the appropriate material to be used as a mould is a critical issue to consider. The figure shows Ti6Al4V alloy microspheres sintered on yttria at 1400°C for 8h. As observed, the mould material remains a critical issue to bear in mind when producing porous Ti6Al4V implants by microsphere sintering. Furthermore, the mechanical properties developed depend on beads size, sintering temperature and time. [Display omitted] ► Porous Ti6Al4V samples have been developed by microsphere sintering. ► Porosity is opened and interconnected, and is suitable for growing bones. ► Influence of process parameters on mechanical properties has been determined. ► Stiffness has been reduced to below 40% of that of the bulk solid material. Two differently sized microspheres were sintered at 1300°C and 1400°C from 2 to 8h in stoneware, alumina, yttria and zirconia moulds. Selecting the appropriate material to be used as a mould remains a critical issue given titanium's high reactivity at elevated temperatures. Optimum mechanical properties were obtained when sintering the smallest microspheres in yttria-coated moulds. Stiffness of the samples was lower than 40% of that of the bulk solid material, which comes closer to that of human cortical bone. Open and interconnected porosity was observed in all the specimens.