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Hyojin Park

Hyojin Park.What is your thesis topic?
My thesis topic is to establish the weldability, characterization of macro/micro-structure, and mechanical performance of lap-jointed Ti-6Al-4V alloy.

How is materials processing involved in your research?
The process involved in my research is frictional stir spot welding (FSSW). This welding process is a novel solid-state joining technique where the metal interfaces are bonded without melting despite significant frictional heating. Additionally, this process results in unique microstructural evolution, leading to the change of mechanical properties. Specifically, titanium and its alloys show a variety of microstructure depending on the thermal processing history. For my study, key objectives are to provide fundamental understanding of the microstructural development/joining mechanism and to establish the relationship among the processing, microstructure, and mechanical performance of the weldments.

Provide an example of where the material, process, or properties you are studying might find an application.
Friction stir spot welding has been applied in many fields, such as aerospace and automotive, in which structural parts are made of aluminum and steel alloy systems. Recently, usage of Ti-alloys is increasing in transportation industries to improve energy efficiency and safety. However, the application of FSSW on Ti-6Al-4V posed several challenges due to the refractory nature of Ti-Alloys. My research on the development of the pinless FSSW of Ti-6Al-4V alloy and the basic understanding of its process couple open it to a variety of new industry applications.