Ti6Al4V foams fabricated by spark plasma sintering with post-heat treatment

Ti6Al4V foams were fabricated by the spark plasma sintering (SPS) with post-heat treatment using a blend of Ti6Al4V and sodium chloride powders. The microstructure and properties of the foams were investigated by scanning electron microscopy, X-ray micro-CT, Synchrotron X-ray, compression test and cell experiments. Results showed that the Ti6Al4V foams fabricated at 700 °C and 50 MPa in the SPS cannot get high relative densities. These sintered foams were post-heat treated in a pressureless mode of the SPS at 1100 °C for 5 min. This heat treatment is very effective to reduce the microporosity and to densify the foam walls. Young's modulus of the foams was in the range of 33.0-9.5 GPa and yield strength ranged from 110.2 MPa to 43.0 MPa with porosity values from 44.7% to 70.0% obeying the Gibson-Ashby models. The human osteoblast cell line MG-63 validated the cellular acceptance of the foam surfaces. The pressureless SPS provides a new method for the heat treatment of metallic foams.