Date of Completion

8-16-2013

Embargo Period

8-16-2013

Keywords

biomaterials, nanomaterials, titanium, hydroxyapatite, functionally graded composites

Major Advisor

Leon Shaw

Associate Advisor

Harold Brody

Associate Advisor

Harris Marcus

Field of Study

Materials Science and Engineering

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Rising costs of health care are attributed to an increasing number of medical procedures with great complexity and costly instrumentation. Novel materials and devices must be developed to reduce the time, economic cost, and physical pain associated with invasive orthopedic surgery. As well the lifetime of components must be extended to meet the needs of a population with an increasing life expectancy. To prolong the lifetime of an implant device, components should closely mimic the naturally occurring biological structure they are replacing in terms of both mechanical and biological function in order to assimilate undetected in the human body. Studies on orthopedic implant materials are herein investigated to determine the feasibility of functionally graded metallic-ceramic composite components that show improved load bearing capability while simultaneously enhancing biological activity necessary to avoid pain and/or device failure. Powder metallurgy studies are conducted using the titanium alloy (Ti-6Al-4V), which has shown great promise in orthopedic implant applications due to its high strength, lightweight, and biocompatible properties. Development of functionally graded titanium-hydroxyapatite components require the co-sintering temperature for the composite to be lowered below the onset of detrimental reactionary products. Powder processing and sintering is used to drive the Ti-HA co-sintering temperature below 1000°C, such that the beneficial mechanical and biological attributes of each constituent are preserved. X-ray diffraction, optical microscopy, and electron microscopy are used to monitor the phase purity, crystal structure, microstructure, particle morphology, particle size and relative density as they relate to the powder processing and sintering phenomena necessary for solid freeform fabrication.

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