THE EFFECT OF TANTALUM CONTENT ON MICROSTRUCTURE AND VICKERS HARDNESS OF TiNbZrTaAg ALLOY

Usually alloys from the titanium-niobium-zirconium-tantalum (TNZT) do not have intrinsic antibacterial properties and to induce such properties introducing alloying elements (silver, in this case) such property can be induced. This research is aimed at studying the influence of tantalum concentration variation on the microstructure of as cast alloys from the TNZT system with 2% silver addition. The alloys were obtained by vacuum-arc remelting (VAR) and characterized by light and scanning electron microscopy, X-Ray diffraction and Vickers hardness tests. The studies are performed on as cast ingots, the intended use for the alloy being dentistry applications. The alloy density was also determined using the water displacement method, the highest tantalum concentration (20%) resulting on a density of 6.87 +/- 0.01g/cm(3). The results showed that the addition of tantalum increases beta-phase content, generates a change in a-phase morphology and increases hardness starting from 15%wt.