In our group, we harness metastable microstructure states (grain boundaries, metastable phases, interfaces, dislocation densities) as a vector to enable next-generation materials. Our current research topics are listed below.
Topic 1: Microstructure engineering with Additive Manufacturing
1.1 : Additive Manufacturing of Immiscible alloys
Heterostructured alloys are revolutionizing materials science by combining multiple phases or microstructures into a single material, achieving exceptional strength, ductility, and toughness. These alloys exploit the synergy between different microstructure regions, such as hard and soft domains, to enable unparalleled performance under extreme conditions. With applications ranging from aerospace to energy, they represent a cutting-edge approach to overcoming traditional trade-offs in structural materials design. Our group specifically develops novel heterostructured alloys using additive manufacturing, with applications in the nuclear, biomedical, and aerospace sectors. These efforts are supported by ARPA-E.
1.2 : In-situ Grain boundary Engineering
AM enables near-net-shaping in a large variety of materials, avoiding machining and reducing waste while saving energy and resources. However it generally induces strongly anisotropic properties, one of the main limitations to its broad adoption. We develop basic understanding of crystal nucleation and growth during AM, and post-processing. This project sees the development of new alloys that exhibit superior mechanical properties through grain refinement, and superior resistance to environmental degradation through grain boundary engineering; in-situ during AM. These efforts are supported by the National Science Foundation.
Topic 2: Radiation-resistant alloys by design
2.1 : Driven alloys
Nuclear energy promises a low-carbon future, but its success hinges on advancing materials that can withstand extreme radiation, high temperatures, and corrosive environments. While most nuclear materials see their performance decrease during service, we go against most efforts in the community and design alloys that self-organize under irradiation, by leveraging dynamic transformations happening during service: radiation-induced segregation (RIS) and precipitation (RIP), radiation-enhanced diffusion (RED), and radiation-induced amorphization (RIA). These efforts are supported by the Department of Energy, Basic Energy Sciences.
2.2 : Radiation-induced heterostructure formation
In existing alloys, the nanometer-scale defects generated by particle irradiation ultimately cause embrittlement and gradual loss of mechanical performance. To date, strategies for mitigating this degradation have centered on introducing microstructural features via alloying or processing, aiming either to slow the accumulation of irradiation-induced defects or to direct them into sinks before they cluster into harmful configurations. However, such microstructure features often lack stability under operating conditions and can merely postpone damage evolution. This project delivers the foundational science behind a novel design concept to create radiation-tolerant alloys by exploiting radiation-induced phase separation (RIPS). The guiding hypothesis is that triggering RIPS in an initially single-phase, chemically uniform alloy, will drive the self-assembly of a dense, stable network of defect sinks in service. This approach marks a shift in paradigm, using radiation itself as a driving force for sink formation instead of treating it solely as a harmful phenomenon to slow down. These efforts are supported by the Department of Energy, Basic Energy Sciences.
Topic 3: Self-adaptive alloys for hydrogen storage
3.1 : Leveraging AM-induced sub-grain structures for superior mechanical properties at cryogenic temperature
Storage and circulation of hydrogen in metals has been a long-standing issue, as it leads to embrittlement at room temperature, and damage at cryogenic temperature (20K). We combine first-principle, thermodynamic calculations, and additive manufacturing to design new alloys that see their performance increase as they are exposed to cryogenic temperatures. Their performance is assessed through statistical measurements of deformation modes over statistically representative microstructure regions. These efforts are supported by the Energy and Biosciences Institute and an ACS New Investigator Award.
3.2 : Harnessing hydrogen-lattice effects
A Hydrogen economy can support deep decarbonization by providing greener and more flexible energy. However, storage and circulation of hydrogen has been a long-standing issue, as it leads to embrittlement at room temperature, and damage at cryogenic temperature (20K). We combine first-principle, thermodynamic calculations, and additive manufacturing to design new alloys that see their performance increase as they are cycled between ambient H-rich environments and cryogenic temperatures. Their performance is assessed through statistical measurements of plastic localization over statistically representative microstructure regions. These efforts are supported by the Energy and Biosciences Institute and Sandia National Laboratories within the Department of Energy.