Production of Ti-13Nb-13Zr alloy for surgical implants by powder metallurgy

The Ti-13Nb-13Zr near-beta alloy was developed aiming the replacement of the traditional Ti-6Al-4V alloy in surgical implants owing to its larger biocompatibility. Samples of this alloy were obtained using the blended elemental technique from hydrided powders. The isochronal sintering of the compacts for 2 h was carried out in the range 900-1,400 A degrees C with a heating rate of 20 A degrees C min(-1). In this work, the behavior of the elementary powders during sintering and the corresponding microstructural evolution were investigated. The alloy was characterized by means of scanning electron microscopy (SEM) in the backscattered mode, X-ray diffraction, and density measurements. The results indicate that the homogenization of the alloy is diffusion-controlled. With increasing temperature, homogenization of the alloy takes place and a fine plate-like alpha + beta structure is found throughout the microstructure in temperatures above 1,300 A degrees C. The process variables were defined aiming to minimize interstitial pick-up (C, O, and N) and avoiding intensive grain growth.