Mechanical properties of open-pore titanium foam.

Open-pore titanium foams are produced using the so-called space holder method. The mechanical properties of titanium foams with porosities of 50-80% are studied. The stiffness and yield strength of the foams are found to encompass the property range between cancellous bone and cortical bone. The analyzed foams are found to be anisotropic due to the use of nonspherical space holder particles which rearrange during the compaction of the powder mixture. The titanium foams are stronger perpendicular to the compaction direction and weaker along the compaction axis. In view of the application as an implant material in the lumbar spine, an intermediate porosity of 60-65% is analyzed more in detail. The typical yield strength of titanium foam with 62.5% porosity is above 60 MPa in compression, bending, and tension. Stiffness values vary with the testing method from 7-14 GPa.