Mechanical strength of extrusion freeformed calcium phosphate filaments

摘要

Hydroxyapatite-tricalcium phosphate mixtures of various compositions were extruded by a solid free-forming process to form lattice structures to serve as hard tissue scaffolds. The unwelded filaments, sintered at temperatures from 1100 to 1300℃, had radii from 115 to 135 μm and were tested in three point flexural loading using a purpose-built fixture. Flexural strength ranged from 20 to 100 MPa depending on composition and sintering temperature. Weibull moduli up to 13 were obtained. Compositions with 50% or more tri-calcium phosphate did not develop strengths much above 40 MPa and the strength of most compositions fell when the sintering temperature exceeded 1250℃. Multiple layer lattice structures were created and tested in compression.