The Effect of Ta, Mg, and Zn Content on the Properties of Ti-Ta-Mg and Ti-Ta-Zn Alloys Prepared by Mechanical Alloying and Hot Pressing

Abstract

The main goal of this study was to achieve poreless titanium alloys with nanocrystalline structure. To this end, the influence of Ta, Mg and Zn content on the properties of Ti alloys was investigated. At first, nanocrystalline powders of TixTayMg and TixTayZn, where x = (30 and 40 wt.%) and y = (3 and 5 wt.%), were prepared using the mechanical alloying process at room temperature. Then, hot-pressing at 750 °C under vacuum was applied for 10 s to consolidate powders. The structure, microstructure, chemical composition, mechanical properties, corrosion resistance, wettability and MTT assay have been investigated. Alloys with Mg were allowed to undergo a shorter mechanical alloying process, achieve greater grain refinement after consolidation and improve mechanical properties. In all cases with increasing amounts of additives in titanium, more Ti-β phase was available. Furthermore, with increasing elements content, hot-pressed alloys consisting of Mg tended to have a more hydrophobic surface. According to the MTT test, all new alloys show non-toxic properties. Among all alloys tested in this study, Ti40Ta5Mg had the most interesting properties for biomedical applications, the highest content of Ti-β phase (81.3%), lowest porosity (0.07%), lowest Young modulus (102.1 GPa) and the lowest surface free energy (38.45 mN/m).