Structure, metallurgy, and mechanical properties of a porous tantalum foam

This study evaluated a porous tantalum biomaterial (Hedrocel (TM)) designed to function as a scaffold for osseous ingrowth, Samples were characterized for structure, Vickers microhardness, compressive cantilever bending, and tensile properties, as well as compressive and cantilever bending fatigue. The structure consisted of regularly arranged cells having struts with a vi treous carbon core,vith layers of CVI deposited crystalline tantalum, Micro hardness values ranged from 240-393, compressive strength was 60 +/- 18 MPa , tensile strength was 63 +/- 6 MPa, and bending strength was 110 +/- 14 MP a. The compressive fatigue endurance limit was 23 MPa at 5 x 10(6) cycles w ith samples exhibiting significant plastic deformation. SEM examination sho wed cracking at strut junctions 45 degrees to the axis of the applied load, The cantilever bending fatigue endurance limit was 35 MPa at 5 x 10(6) cyc les, and SEM examination showed failure due to cracking of the struts on th e tension side of the sample. While properties were variable due to morphol ogy, results indicate that the material provides structural support while b one ingrowth is occurring. These findings, coupled with the superior biocom patibility of tantalum, makes the material a candidate for a number of clin ical applications and warrants further and continued laboratory and clinica l investigation. (C) 2001 John Wiley & Sons, Inc.