Microstructural Evolution during Sintering of the P/M Blended Elemental Ti-5Al-2.5Fe Alloy

The alpha-beta Ti-5%Al-2.5Fe (wt-%) alloy was developed as a cost-effective option to replace the traditional Ti-6%Al-4%V alloy in the manufacture of surgical implants because of its larger biocompatibility (V-free alloy). Samples of this alloy were prepared using the blended elemental (BE) technique. The isochronal sintering of the cold pressed compacts was carried out at 700, 1000, and 1400°C in vacuum. In this work, the preliminary results of the behavior of elementary powders during sintering and the corresponding microstructural evolution are shown. The alloy was characterized by means of scanning electron microscopy (SEM) in the backscattered mode, X-ray diffraction (XRD), energy-dispersive spectrometry (EDS), and density measurements. The results indicate that the homogenization of the alloy is diffusion-controlled. Non-equilibrium Ti-Al phases as well as Fe-Al compounds were identified in samples sintered at lower temperatures (700oC). With increasing temperature, homogenization of the alloy takes place and a structure consisting of coarse plate-like alpha and intergranular beta is present.