Abstract:
Titanium-tantalum (Ti-Ta) alloys are likely to have a high biocompatibility and corrosion resistance that renders them novel materials of interest for biomedical applications[7, 14, 2]. With high strength and a low elastic modulus, Ti-Ta alloys have attracted attention as candidates for such uses as hip replacements[2]. A current challenge impeding use of these alloys is that, with a melting temperature of 3269 K, homogeneous alloys involving Ta are difficult to produce by conventional melting practice[3]. The objective of this work was to, as most structural changes occur via diffusion, gain insight into this matter through determination of the interdiffusivity in Ti-Ta alloys. A scanning electron microscope was utilized to perform energy dispersive x-ray analysis on Ti-Ta alloy samples in the range of 20 to 60 weight percent (wt %) Ta. A computational model that employed Fick's Second Law was used to extract interdiffusivity values from the data. Interdiffusivity values, which ranged from 4.0. 10-13-Tfor 20 wt % Ta to 3.0. 0-14- for 60 wt % Ta, exhibited a systematic variation with composition. The interdiffusion coefficient was seen to decrease with increasing weight fraction Ta.
Description:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.Includes bibliographical references (leaves 33-34).
