Sudip Saha

Date of Award

January 2023

Document Type


Degree Name

Master of Science (MS)


Mechanical Engineering

First Advisor

Sougata Roy


Tribological analysis of metallic implants for orthodontics applications is a long-studied topic of research. The study covers human mouth anatomy, implant types, and major wear mechanisms, materials, and manufacturing techniques commonly used for dental implant materials. Common contributing factors to evaluate the mechanical performance of metal implants includes tribological behavior analysis in varying physiological conditions, material properties, corrosive responsiveness and manufacturing techniques. By conducting systematic experiments to cover these areas, this study aims to evaluate the performance of wrought and additively manufactured Co-Cr alloy for metallic implants for orthodontics applications.For the tribological test and corrosion experiments laboratory prepared artificial saliva solution was leveraged as lubricant and electrolyte respectively. From varied pH level of artificial saliva, the most corrosive solution was identified experimentally and was chosen for further experimental use. Ball-on-flat type reciprocating friction and wear testing was used to simulate contact conditions of implants under dry and saliva-lubricated conditions. The wear tracks were analyzed after the experiments using interferometry and microscopy techniques to analyze the wear mechanisms. The result revealed additively manufactured CoCrMo had superior hardness, refined grain structure and enhanced tribological performance compared to CoCrW attributed to synergistic effect of decreased grain size, formation of stable passive layer and higher surface hardness due to Mo as alloying element. For both wrought and additively manufactured Co-Cr alloy, abrasion was the predominant wear mechanism with the presence of adhesive material transfer. Adhesive material transfer from flat to ball was more prominent for CoCrMo, and deposited material on the ball surface protected the ball from further wear during the experiments. From the potentiodynamic polarization analysis, CoCrW displayed superior corrosion resistance while CoCrMo showcased a longer passive state. These findings will provide major insights into Co-Cr alloy based dental prosthetics development using wrought and metal additive manufacturing process along with next generation in-situ alloy development for select biomedical applications.

Available for download on Thursday, June 06, 2024