Experimental investigation of FGM dental implant properties made from Ti/HA composite

Although titanium-hydroxyapatite (Ti-HA) composite is an attractive material to use as dental implant, it would be more useful if it could be produced as functionally graded material (FGM). In this paper, microstructure and micro-hardness of a five-layer titanium-hydroxyapatite functionally graded material are investigated in different layers. First, titanium and hydroxyapatite powders have been mixed together during planetary ball-mill process under argon atmosphere. The mixing ratios (titanium to hydroxyapatite volume ratio) are 100:0, 90:10, 80:20, 70:30 and 60:40 for five layers. The obtained powders have been poured in a graphite mold functionally and then sintered by using spark plasma sintering (SPS) method. Micro-hardness and microstructure of the samples are examined by using micro-Vickers hardness test and optical microscopy. The results show that hydroxyapatite particles have an acceptable distribution in titanium matrix and grain refinement occurs in Ti-HA composite in comparison to monolithic Ti layer. Moreover, the layers with 30 vol.% and 40 vol.% hydroxyapatite have the highest and the lowest micro-hardness of matrix, respectively.