Hyunsuk Choi

Date of Award

January 2023

Document Type


Degree Name

Master of Science (MS)


Mechanical Engineering

First Advisor

Sougata Roy


The manufacturing industry is constantly looking for ways to improve processes and reduce costs while maintaining or enhancing material properties. Nickel-Titanium (NiTi) alloy, also known as Nitinol, has unique properties such as shape memory and superelasticity, which make it a valuable material for various applications in the medical and aerospace industries. However, due to its high toughness, strength, and ductility, NiTi is difficult to form and machine, leading to severe tool wear and high cutting energy. Conventional manufacturing processes have limitations in producing complex or porous designs, restricting NiTi's potential applications. Additive manufacturing techniques have been explored as a way to expand the range of NiTi applications. This thesis investigates the tribological and mechanical behavior of 55 NiTi alloys under various conditions. The study explores the influence of manufacturing processes, operating temperatures, and location dependence on the tribological and mechanical behavior of the alloy. The investigation provides various approaches for producing 55 NiTi alloys with satisfactory properties and explores the use of additive manufacturing techniques for tribological applications in extreme environments, space applications.