A seminar by Penghui Cao
Feeling social? Share this.
Fusion is entering a decisive transition from scientific feasibility to engineering realization, placing unprecedented demands on materials. Structural materials must withstand extreme radiation and heat while retaining thermomechanical integrity. Yet even tungsten, a leading candidate, suffers from defect clustering and radiation-induced embrittlement, limiting component lifetime and challenging the viability of fusion energy.
In this presentation, I will discuss the mechanistic understanding and control of defect kinetics in alloys under irradiation. Using a neural-network kinetics approach with efficient representations of local structure and chemistry, we predict atomic diffusion and long-time defect evolution in concentrated alloys. Exploring the vast compositional space, we show that a tungsten multicomponent alloy fragments vacancy diffusion pathways, reducing their connectivity below the percolation threshold and thereby kinetically trapping defects. The diffusion fragmentation suppresses vacancy-cluster growth, confirmed by irradiation experiments and atomic-scale characterization, which reveal minimal defect coarsening despite orders-of-magnitude increases in radiation dose. These results demonstrate a new paradigm of percolation-engineered kinetics and provide a predictive pathway for discovering inherently radiation-resistant alloys for fusion energy systems.
Penghui Cao is an Associate Professor of Mechanical and Aerospace Engineering at the University of California, Irvine, with a joint appointment in Materials Science and Engineering. He completed postdoctoral training in the Department of Nuclear Science and Engineering at MIT. Dr. Cao’s research focuses on uncovering the fundamental mechanisms governing radiation damage and microstructural evolution under extreme nuclear energy environments. His group develops computational materials algorithms, combined with irradiation testing and electron microscopy, to reveal underlying mechanisms and guide the design of radiation-tolerant materials.
He leads a University of California multicampus fusion initiative on the predictive discovery of radiation-resistant alloys for extreme fusion energy, in collaboration with LANL and LLNL. He is the recipient of the DOE Early Career Research Program Award (ECRP) and the UCI Samueli School’s Mid-Career Award for Faculty Excellence in Research.
