Spark Plasma Sintering, Microstructures, and Mechanical Properties of Macroporous Titanium Foams

Macroporous pure titanium (Ti) foams with porosity of 30-70% and pore size of 125-800 mm were fabricated by using spark plasma sintering (SPS) and NaCl dissolution methods. A mixture of Ti and sodium chloride (NaCl) powders were spark plasma sintered in a temperature range from 550 to 800 degrees C and the NaCl phase was then dissolved in water. High purity Ti foams were obtained at the SPS temperature of 700 degrees C for holding time of 8 min under pressure of 50 MPa. The resulting Ti foams consist of pure alpha-Ti phase with interconnected macropores in square cross sections. The plateau stress and Young's modulus agree with the Gibson-Ashby models, and coarsely follow of linear decline with the increase of the pore sizes, and exponential decay with the increase of the porosity. The macroporous Ti foams with plateau stress 27.2-94.2 MPa and Young's modulus 6.2-36.1 GPa may have a potential to be used as bone implants.