DESIGN AND FABRICATION OF A NEW FGM IMPLANT

Nowadays, there is a growing need for using functionally graded materials (FGM) for using in bio-medical application. This need is prominent especially for the effect of gradient structures and in implant applications. To optimize both mechanical and biocompatibilities properties or change bio reactivity in each region, powder metallurgy technique is used in this study to fabricate titanium/hydroxyapatite (Ti/HAP) and other FGM implants with the concentration changed gradually in the longitudinal direction of cylindrical shapes. Concentration gradient was formed by packing dry powders into mold or sedimentation in solvent liquid processes. For the sintering process, three spark plasma sintering (SPS), high-frequency induction heating and electric furnace heating techniques were used to sinter the materials. During the fabrication of Ti/HAP FGMs and due to the stress relaxation in the implanted regions of bones, Brinell hardness decreased gradually from Ti part to HAP part. The results showed that the tissue reaction occurred gradiently in response to the graded structure of the FGM, which implies the possibility of controlling the tissue response through the gradient function of the FGM.