Jian Luo

UC San Diego NanoEngineering Department Portraits April 3, 2023

Computing Grain Boundary Phase (Complexion) Diagrams and Controlling Microstructures with Electric Fields

The materials science community has long recognized that grain boundaries (GBs) can be treated as two-dimensional (2D) interfacial phases, which were also named as “complexions” to differentiate them from bulk phases. Such 2D interfacial phases can process distinct interfacial structures that are neither observed nor stable as bulk phases [see, e.g., a recent perspective article: Science 368, 381 (2024)]. As bulk phase diagrams are arguably the most useful materials science tool, this presentation will first review a series of our studies to compute the GB phase (complexion) diagrams via thermodynamic models, atomistic simulations, and machine learning [as summarized by a review and perspective article: Interdisciplinary Materials 2:137 (2023)]. In addition to temperature and chemical potentials, an applied electric field can induce a GB transition electrochemically [Nature Communications 12:2374 (2021)]. Recent studies further utilized electrochemically induced GB transitions to tailor microstructural evolution and create graded microstructures [Materials Today 73:66 (2024) and unpublished results].

Biographical Sketch

Jian Luo graduated from Tsinghua University with dual Bachelor’s degrees: one in Materials Science and Engineering and another in Electronics and Computer Technology. After receiving his M.S. and Ph.D. degrees from M.I.T., Luo worked in the industry for over two years with Lucent Technologies Bell Laboratories and OFS. In 2003, he joined Clemson University, where he served as an Assistant/Associate/Full Professor of Materials Science and Engineering. Since 2013, he is a Professor of Chemical and Nano Engineering and Professor of Materials Science and Engineering at the University of California, San Diego (UCSD). Luo group’s current research focuses on interfaces in ceramics and metals, high-entropy and compositionally complex ceramics, ultrafast sintering and other novel ceramic processing technologies, high-temperature nanocrystalline alloys, and advanced materials for batteries and other energy-related applications. Luo received a National Science Foundation CAREER award in 2005 and an AFOSR Young Investigator award in 2007. He is a Vannevar Bush Faculty Fellow (2014), a Fellow of the American Ceramic Society (2016), a Minerals, Metals & Materials Society (TMS) Brimacombe Medalist (2019), a Fellow of the ASM International (2022), and an Academician of the World Academy of Ceramics (2021). Luo served as the Chair for the Basic Science Division of the American Ceramic Society for 2012-2013 and chaired the Solid Studies of Ceramics Gordon Research Conference in 2018.