Ti–SrO metal matrix composites for bone implant materials

Abstract

Titanium–strontia (Ti–SrO) metal matrix composites (MMCs) with 0, 1, 3 and 5% (weight ratio) of SrO have been fabricated through the powder metallurgy method. Increasing the weight ratio of SrO from 0 to 5%, the compressive strength of Ti–SrO MMCs increased from 982 MPa to 1753 MPa, while the ultimate strain decreased from 0.28 to 0.05. The elastic moduli of Ti–3SrO and Ti–5SrO MMCs were higher than those of Ti and Ti–1SrO MMC samples. Additionally, the micro hardness of Ti–SrO MMCs was enhanced from 59% to 190% with the addition of SrO. The enhanced compression strength and micro hardness of Ti–SrO MMCs were attributed to the Hall–Petch effect and the SrO dispersion strengthening in the Ti matrix. MTS assay results demonstrated that Ti–SrO MMCs with 3% SrO exhibited enhanced proliferation of osteoblast-like cells. Alkaline phosphatase activity of cells was not influenced significantly on the surface of Ti–SrO MMCs compared with pure Ti in a term longer than 10 days. The cell morphology on the Ti–SrO MMCs was observed using confocal microscopy and scanning electron microscopy, which confirmed that the Ti–3%SrO MMCs showed optimal in vitro biocompatibility.