H. Fisher, S. M. Abkowitz, S. Abkowitz, Dynamet Technology, Inc., Burlington, MA; S. M. Allen, Massachusetts Institute of Technology, Cambridge, MA
This paper reports the results of initial research on the potential of Ti-Ta compositions for use implantable medical device alloys. Titanium-tantalum alloys are of interest for such applications because they are highly biocompatible and have a very low modulus of elasticity at lower Ta contents, making them potential candidates for orthopaedic and dental implants. At higher Ta compositions Ti-Ta alloys undergo martensitic transformations that are indicative of potential superelastic or shape memory behavior required for self expanding vascular stents. These alloys are very difficult to prepare by conventional methods due to the disparity in melting points and density between Ti and Ta that causes extensive segregation of the alloy ingredients. A Ti-30 wt%Ta alloy, of particular interest because of its low modulus, was prepared by powder metallurgy processing. Innovative powder metallurgical technology was also used to produce single bars within which the composition varied systematically from 20% Ta to 60% Ta, making it possible to scan for properties across a wide range of Ti-Ta compositions. The paper describes the use of micro-analytical techniques to derive property and compositional data from these bars. Preliminary property data is reported that hold promise for the use of Ti-Ta in future implantable medical devices.
Summary: This paper presents initial research on the potential of Ti-Ta alloys for use in medical devices. Compositions ranging from 20-60wt%Ta were produced using powder metal techniques. Preliminary results show that compositions in the Ti-Ta system offer potential benefits as alloys for orthopaedic, dental and stent applications.
