Research
Our interest is exploring the structure-property-processing relationships in structural metals and advanced materials, with particular emphasis on size effect, structural disorder, and extreme processing conditions, and their roles in mechanical and functional properties. Our research utilizes integrated computational materials science and engineering (ICME) approach, coupling multi-scale materials modeling and simulations, analytical theories, and experimental means to establish connections between atomic process and macroscopic material performance, particularly for amorphous alloys, nanostructured alloys, additive manufactured metals, and low-dimensional materials.
Metallic Glasses
Stronger than steels but able to be shaped and molded like plastics, metallic glasses (MGs) are quintessential engineering materials, and are currently among the most actively studied metallic materials. Despite intensive research underway, the quantitative structure-property relationships of MGs have remained a long-standing mystery. On the one hand, MGs do not have distinct structural defects, exhibiting invariably amorphous structures without discernible microstructure; on the other hand, topological and chemical short-to-medium range order is present, acting as defect-like inside the seemingly structure-less glass. Our research goal is to establish quantitative structure-property relationships in MGs by developing a physics-driven structural descriptor and its dynamical laws that correlate with the evolution of complex glassy state and predict mechanical properties, using multi-scale simulations, experiments, and machine-learning models.
Nanostructured Metallic System
Nanocrystalline metals represent a class of high strength engineering materials with compelling benefits for the electronics, aerospace, automotive industries. However, the applications have been significantly limited by their thermal instability against grain coarsening as well as a lack of ductility. A state-of-the-art strategy to address these limitations is termed grain boundary complexion engineering, which tailors the grain boundary equilibrium structures via segregating dopant atoms. The research focuses on understanding the the disordered state of grain boundary complexion, and the cooperating and competing deformation mechanisms in the complexion-engineered nanocrystalline metals, and elucidating their hierarchical contributions to the exceptional mechanical performance.
Inconel 718 Fabricated by Selective Laser Melting
Additive manufacturing (AM) of metal components is a rapidly growing manufacturing paradigm that could revolutionize the design and production of complex metallic parts. However, the extreme processing conditions create unique material microstructures (e.g., various metallic phases, textures, localized stresses) that can affect their performance. This program is to understand the relationship of process, microstructural evolution and mechanical performance of AM metal components using an integrated computational materials engineering (ICME) approach.
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