Session: Rising Stars of Mechanical Engineering Celebration & Showcase

Paper Number: 147978

147978 - Wire Arc Additive Manufacturing of Molybdenum Alloy for High-Temperature Applications: Residual Stresses and Porosity Considering Ductile-to-Brittle Transition Temperature 

Overview:

The research and educational activities outlined in this CAREER proposal will provide a solid foundation for the PI’s successful academic career while supporting the vision of Tennessee Tech for their faculty and students. The PI’s long-term research goal is to create fundamental knowledge of integrated computational materials engineering (ICME), enabling the field to realize the paradigm shift from “apply the alloy you have” to “engineer the alloy you need.” Specifically, the PI aims to establish additive manufacturing (AM) design rules for refractory high entropy alloys. In the pursuit of this goal, the research goal for this project is to explore and elucidate the root-causes of imperfections and the associated negative effects to the thermomechanical performances of additively-manufactured molybdenum (Mo) alloy structures at room to elevated temperatures, focusing on titanium-zirconium-molybdenum (TZM). To achieve the goal, an integrated experimental and computational modeling approach will be used. The overarching educational goal is to develop a new initiative for workforce development, providing students with cutting edge skills and knowledge in emerging technology-intensive manufacturing and data science disciplines. In this project, the PI aims to (1) enhance the existing curricula (MET4220/5220: Industrial Automation and Robotics and MET4250/5250: Applied Mechatronics); (2) provide undergraduate/graduate student internship at national research labs to broaden their views and knowledge; and (3) provide hands-on experiences to underrepresented K-12 students. The PI’s ultimate career goal is to be a pioneer and premier educator in fundamental research using innovative technologies, especially AM for refractory alloy structures. This proposed CAREER project will be the foundation to achieve this goal.

 

Intellectual Merit:

Fundamental knowledge will be generated by exploring and quantifying the complexity and variability from the non-equilibrium AM thermal cycles and the unique properties in refractory alloys through a multi-scale, multi-fidelity, in-situ materials characterization and physics-informed, data-driven approach. Specifically, this project will (1) create new knowledge about the residual stress development and pore creation mechanisms in AM for refractory alloy structures, with the consideration of ductile-to-brittle transition temperature (DBTT) and (2) elucidate the thermomechanical properties and deformation behaviors at room to elevated temperatures, as correlated with heterogeneous microstructures and oxidation. Ultimately, a quantitative process-signature-structure-property-performance (PS²P²) linkage, called the “design rule,” will be established for AM processes toward satisfactory fabrication of refractory alloy structures. The linkage will serve as a powerful, effective tool to tailor the microstructures and properties, leading to control and improvement of the thermomechanical performances of the final part.

Broader Impacts:

This project will provide transformative knowledge and scalable methodology to industries, leading to greater efficiency and improved profitability. For example, the results can be used to improve the energy efficiency in land-based power plants by replacing the current nickel-based parts with molybdenum-based ones, leading to a reduced carbon footprint and more sustainable clean energy. Specifically, if the operating temperature increases up to 100°C in a 1000 MW gas-fired combined-cycle gas turbine power plant, the thermal efficiency will increase by 1.9%. This increase can reduce the CO₂ emission by more than 50,000 tons/year. The knowledge gained from this project is also transformative for other refractory alloys (e.g., tungsten and niobium), including refractory high entropy alloys. In addition, the educational and outreach activities integrated as part of this project will help develop the skills of K-12, undergraduate, and graduate students, including underrepresented minorities. These activities will also provide accelerated pathways for students by encouraging them to pursue careers in science, technology, engineering, and mathematics (STEM) areas.

Presenting Author: Duck Bong Kim Tennessee Tech University

Presenting Author Biography: Dr. Duck Bong Kim is an associate professor at the department of Manufacturing & Engineering Technology and joint faculty at Mechanical Engineering as well as Electrical and Computer Engineering at Tennessee Technological University. He had been working as a research associate at the National Institute of Standards & Technology (NIST), Maryland, USA (2011 - 2016). With a PhD and MS in School of Information and Mechatronics from Gwangju Institute of Science & Technology (GIST), Korea, Dr. Kim is a cross-disciplinary research scientist with knowledge & experience in advanced design & manufacturing engineering: smart manufacturing, additive manufacturing (3D Printing), wire+arc additive manufacturing (WAAM), sustainable manufacturing, data analytics, & machine vision. Currently, he is focusing on wire + arc additive manufacturing for refractory alloys (e.g., Titanium-Zirconium-Molybdenum) fabrication by supporting from an NSF CAREER program.

Authors:

Duck Bong Kim Tennessee Tech University