Yu Research Group
About Us
The Yu Research Group is committed to educating future engineers, expanding the boundaries of knowledge, and creating solutions for the world’s most critical challenges in advanced materials and manufacturing. The Yu Research Group is specifically recognized as a pioneer of solid-state metal additive manufacturing via additive friction stir deposition (or AFSD), which is characterized by rapid and extensive shear flow at elevated temperatures. Compared to mainstream fusion-based metal additive manufacturing, this process has demonstrated salient advantages in quality, properties, cost, and resilience. Our laboratory is featured in a YouTube Video: AFSD - LARGE METAL 3D PRINTING! (hosted by 3D Printing Nerd).
Our research delves into the processing and materials science of advanced manufacturing—including processing physics, mechanics, and the underlying peculiar kinetic phenomena—with the goal of gaining unprecedented fundamental insights and translating new knowledge into game-changing engineering applications in repair, recycling, and autonomous, resilient manufacturing:
Basic Processing and Materials Science: The extensive shear-driven printing process is characterized by continual, sustained supply of energy and external forcing, therefore providing a good experimental platform to explore the unique kinetic phenomena under far-from-equilibrium, 'driven' conditions, which may not be properly described using linear irreversible thermodynamics applicable to near-equilibrium scenarios. We are interested in exploring the fundamentals of atomic transport (e.g., shear-induced segregation/mixing), microstructure evolution (e.g., continuous/discontinuous dynamic recrystallization; mechanical instability of inclusions), phase transformation, and interface bonding-- all under external force-driven conditions. Through in situ or time-resolved characterization and theoretical innovation (based on variables that can be measured in experiments to test the theory), we aim to gain an in-depth understanding of the phenomenological laws and governing mechanisms behind these intriguing processes.
Game-Changing Engineering Applications: With the gained process and materials science fundamentals, we seek to establish quantitative process-structure-property linkages and advance supply-chain resilience and material sustainability through game-changing applications in recycling, repair, and autonomous, resilient manufacturing. Additionally, through collaboration, we are exploring advanced quality control schemes in solid-state additive manufacturing enabled by the integration of in situ monitoring, physics simulation, and Bayesian learning-based prediction. Material systems of interest include precipitate-strengthened alloys (e.g., aerospace grade 7xxx and 2xxx Aluminum), two-phase alloys (e.g., Ti-6Al-4V), immiscible binary systems, as well as functional materials, such as magnetic materials and shape memory alloys and composites. Applications of interest include structural repair, solid-state recycling (and upcycling), underwater printing, and robotic AM.
* Professor Hang Yu is a recipient of the DARPA (Defense Advanced Research Projects Agency) Young Faculty Award. In the capacity of the lead PI, Professor Hang Yu has received a DURIP (Defense University Research Instrumentation Program) Award of $800,000. This generous grant enabled the acquisition and installation of a state-of-the-art MELD L3 metal 3D printer, further enhancing our research capabilities. Our research group is also actively involved in contributing to the development of the world's largest metal 3D printer (Rock Island Arsenal, IL).
* Professor Hang Yu has recently published a monograph titled 'Additive Friction Stir Deposition' (Elsevier, 2022). He has collaborated with Dr. Nihan Tuncer (Foundation Alloy) and Dr. Zhili Feng (Oak Ridge National Laboratory) to edit a new book titled 'Solid-State Metal Additive Manufacturing: Physics, Processes, Mechanical Properties, and Applications' (Wiley-VCH, 2024).
*We are delighted to share some articles highlighting the achievements of our research group: 'Research and Industry Partnership Helps Forge 21st Century Metallurgy'; American Chemistry Society: 'Metal 3D Printing Is Showing Its Mettle'; Mechanical Engineering Magazine (ASME): Engineers Scale Up Smart Ceramic Composites. These articles provide insights into the impactful work by our team.
*Student Achievement: Dr. Greg Hahn was named the 2023 outstanding graduate in MSE. Dr. Mackenzie Perry won the 2021 Acta Student Award.