The Effect of Equal Channel Angular Extrusion (ECAE) and Boron Additions on the Mechanical Properties of a Biomedical Ti-Nb-Zr-Ta (TNZT) Alloy

New metastable-beta type titanium alloys based on the biocompatible elements Ti-Nb-Zr-Ta: TNZT) have been developed to address the shortcomings: e.g. incomplete biocompatibility, high modulus, etc.) of the traditionally used materials in joint replacement prostheses. Equal channel angular extrusion: ECAE) processing has the capability to improve the mechanical properties of these alloys to broaden their potential biomedical applications. The focus of this investigation is to evaluate and optimize the ECAE process to produce maximum property improvement, and explore the effectiveness of boron as a grain refining agent. Deformation mechanisms are identified for various processing conditions, and the strain distribution induced during extrusion is examined using finite element techniques. Multi-pass ECAE processed samples were examined using optical and transmission electron microscopy, and subjected to tensile, fatigue, and wear testing. It was found that ECAE has a beneficial impact on all of the properties tested. The modulus value was increased by approximately 25 percent, but it is still well below the value of other prosthesis materials.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering and Materials Science

Year dc:date.available

2010

Author dc:creator

• Colombo, Gian

Contributors dc:contributor

• Shankar Sastry

• Engineering
• Metallurgy

Language dc:language

English (en)

DOI

https://doi.org/10.7936/K7RR1W9T

OAI identifier oai:identifier

oai:openscholarship.wustl.edu:etd-1072