Fabrication and characterization of titanium-matrix composite with 20 vol% hydroxyapatite for use as heavy load-bearing hard tissue replacement

Abstract

Titanium-matrix composite with 20 vol% HA ceramic was fabricated by hot pressing technique and the microstructure of the composite was studied by transmission electron microscope (TEM). The mechanical and biological properties of the composite were investigated by mechanical and in vivo studies. The experimental results by TEM observation show the bonding state of Ti/HA interface in Ti-20 vol% HA composite with the relative density of 97.86% is good, however, there exists an interfacial transition zone between Ti and HA. In Ti matrix of the composite and pure Ti metal, an interesting substructure comprised of screw dislocations with Burgers vectors b of 1/3 < 11 20> was found. Screw dislocations are straight and regularly distributed, and cross slip can be observed. The subgrain boundaries consist of dislocation network walls with equidistant dislocation lines in the same direction. Elastic modulus and Vicker's hardness of Ti-20 vol%HA composite are 102.6 GPa and 3.41 GPa respectively. Owing to the existence of 20 vol% HA ceramic, bending strength and fracture toughness of the composite decrease sharply to 170.1 MPa and 3.57 MPa.m(1/2) respectively, which are only about 17.5 and 12% of those of pure Ti metal. In vivo studies indicate Ti-20 vol% HA composite has good biocompatibility, and even better osteointegration ability than pure titanium, especially in the early stage after the implantation. In conclusion, Ti-20 vol% HA composite is suitable for heavy load-bearing hard tissue replacement from the point of view of both mechanical properties and biocompatibility.

Calcium orthophosphate-based biocomposites and hybrid biomaterials

“…Similar findings had been earlier made for HA bioceramics reinforced by addition of silver particulates (5-30 vol.%) and subsequent sintering of the HA/Ag powder compacts [838,839]. Other studies on calcium orthophosphate/Ti biocomposites are available elsewhere [845][846][847][848].…”

Biocomposites and hybrid biomaterials based on calcium orthophosphates

“…1003,1004 Various biocomposites of calcium orthophosphates with metals and alloys have been fabricated as well. 540,928,967,997,[1028][1029][1030][1031][1032][1033][1034][1035][1036][1037][1038][1039][1040][1041][1042][1043][1044][1045] For example, an HA-based biocomposite reinforced with 20 vol.% of Ti particles was fabricated by hot pressing. 1030 Calcium orthophosphate/Ti biocomposites might be prepared by powder metallurgy ©2 0 1 1 L a n d e s B i o s c i e n c e .…”

Materials in particulate form for tissue engineering. 1. Basic concepts

“…Ceramic materials, such as tricalcium phosphate (TCP), hydroxyapatite (HA) and bioactive glasses (BG) have been widely investigated for hard tissue applications (Balla et al, 1991;Schepers et al, 1991Schepers et al, , 1993Schepers et al, , 1998Meenen et al, 1992;Gatti et al, 1994;Schepers and Ducheyne, 1997;Chu et al, 2002;Huygh et al, 2002;Artzi et al, 2005;Kim et al, 2005;Chu et al, 2006), for filling, support and promotion of regeneration. Their role as drug delivery devices derives from their compatibility and physical characteristics, such as non-immunogenicity and degradability.…”