Tensile Property, Corrosion Resistance and Cytocompatibility of Tungsten Short Fiber Reinforced Ti-6Al-4V Alloy

Abstract

Tungsten short fiber reinforced Ti–6Al–4V alloy has been investigated in terms of its tensile properties, corrosion resistance and cytocompatibility. This composite material was fabricated by a hot isostatic pressing process. The room temperature tensile strength and the 0.2% proof stress were very high, approximately 1300 MPa and 1200 MPa, respectively. These strengths are excellent compared to those of the existing biomaterial of titanium-base. The cytocompatibility of this composite material was evaluated using the anodic polarization test and the cytocompatibility test to clarify the possibility of its application as a structural biomaterial. Anodic polarization tests in Eagle’s minimum essential medium and in 1 mass% lactic acid were carried out to investigate the corrosion resistance of the composite material in vivo. The current density at the entrance to the passive region of the composite material tended to increase more than that of Ti–6Al–4V alloy. However, the passive region was retained at a potential of about 2 V, which is sufficiently high compared to the potential in vivo. In addition, the cytocompatibility was evaluated by investigating the relative growth ratio of fibroblast L929 cells after four days incubation on the test material. The relative growth ratio is obtained as follows: number of cells on the test material/number of cells on the reference material (control). The relative growth ratio of the composite material in making Ti–6Al–4V alloy into a control was 0.9032. According to the result of ICP-MS analysis, the concentration of tungsten in the medium after four days of incubation on the composite material was high compared to that of titanium, aluminum and vanadium.