Processing of porous Ti and Ti5Mn foams by spark plasma sintering

Titanium and its alloys are one of the best metallic biomaterials to be used for implant application. In this study, porous Ti and Ti5Mn alloy with different porosities were successfully synthesized by powder metallurgy process with the addition of NH4HCO3 as space holder and TiH2 as foaming agent. The consolidation of powder was achieved by spark plasma sintering process (SPS) at 16 MPa and pressureless conditions. The morphology of porous structure was investigated by using scanning electron microscopy (SEM) and X-ray micro-tomography (μ-CT). Nano-indentation tester was used to evaluate Young's modulus of the porous Ti and Ti5Mn alloy. Experimental results showed that pure Ti sample, which sintered under pressure of 16 MPa, full relative density was achieved even at a relative low sintering temperature 750 oC; however, in the case of pressureless condition at sintering temperature 1000 oC the porosity was 53% and Young's modulus was 40 GPa. The Ti5Mn alloy indicated a good pore distribution, and the porosity decreased from 56% to 21% by increasing the sintering temperature from 950 oC to 1100 oC. Young's modulus was increased from 35 GPa to 51.83 GPa with increasing of the sintering temperatures from 950 oC to 1100 oC.