Study of the microstructure and mechanical properties of beta tricalcium phosphate-based composites with alumina addition produced by powder metallurgy

Abstract The use of alumina as a reinforcement in metallic and ceramic matrix is well-known. The purpose of this study was to investigate the effect of alumina addition according to its amount on the microstructural and mechanical behavior of tricalcium phosphate ceramic (TCP), more specifically the β-TCP. Although β-TCP has excellent bioactive and biocompatible properties, it presents low fracture resistance and load bearing capacity, which limits its use in the monolithic form. The route used for the β-TCP/alumina composite production was powder metallurgy. The powders were milled in a high energy ball mill with the following parameters: 5, 10, 15 and 20 hours, mass/sphere relation of 1:20 and speed of 150 rpm. After the milling process, the powders of both compositions were uniaxially pressed and sintered. Two of the compositions were processed containing 90% and 50% of β-TCP, respectively. The results indicated that composition 1 with a smaller percentage of alumina in its microstructure presented 62.4 % smaller particle size after the high energy ball milling process, which provided higher densification after pressing and sintering. These results implied in increased mechanical resistance, with 4.6 GPa of elastic modulus and 140 MPa of compressive strength, against 3.6 GPa of elastic modulus and 117 MPa of compressive strength obtained in composition 2.