Thermodynamically Consistent Differentiable Computational Mechanics Methods for High-Temperature Deformation in Structural Alloys
Under prolonged high-temperature loading, deformation is governed by the coupled evolution of dislocation structures (multiplication, interactions, recovery), point defects (vacancies, interstitials), and grain boundaries. These mechanisms evolve continuously over time, depend strongly on prior loading history, and span multiple length and time scales. Existing computational methods either resolve these mechanisms using computationally intensive atomistic and crystal plasticity simulations or replace them with empirical constitutive equations that often fail when extrapolated to new alloy chemistries, processing routes, or service conditions.
The objective of this research is to develop a new computational paradigm for predicting history-dependent materials behavior via differentiable computational mechanics. Specifically, this research will develop a thermodynamically consistent constitutive evolution operator capable of learning the governing evolution physics of microstructural features during high-temperature creep. By learning the evolution of the material state (i.e., internal state variables), the resulting framework will remain physically interpretable, transferable across loading histories, and extensible to other operator-learning architectures. The long-term vision is to establish a differentiable digital twin capable of rapidly predicting high temperature deformation evolution, quantifying uncertainty, and accelerating the computational design of structural alloys for extreme environments.
Engineering Coupled Chemomechanical SRO-Dislocation Behaviors to Improve Mechanical Performance in Alloys (Collaboration with AU)
Localized slip, damage accumulation, and crack evolution govern the failure of structural alloys operating under thermomechanical extremes. Compositionally complex alloys (CCAs), particularly body-centered cubic refractory medium/high entropy alloys, have emerged as promising candidates for aerospace applications, as these materials can maintain strength on the order of several hundred MPa even at temperatures exceeding 1000C. Among others, their chemical complexity engenders a strongly heterogeneous stacking fault energy (SFE) landscape and gives rise to nanoscale short-range order (SRO) that significantly alter dislocation energetics and mobility (beyond conventional solid-solution strengthening), thus influencing plastic deformation and damage evolution under thermomechanical extremes.
The objective of this project is to engineer the local chemical order in ternary BCC systems to improve thermomechanical performance for extreme environment applications. This project is being performed in collaboration with Auburn University.
Developing Microstructure Aware Models for Plastic Deformation in Alloys Subjected to Thermomechanical and Irradiation Conditions (Collaboration with LANL and UTK)
Complex, coupled stimuli, such as stress, high temperature, and irradiation can often activate accommodation modes that adversely alter the deformation response of the material (e.g., promote strain localization, embrittlement, etc.). The objective of this project is to elucidate how these anomalous accommodation modes emerge and quantify their dependence on both the intrinsic microstructure (grain boundaries, dislocation networks/cells, and precipitates) and the external stimuli. This project is being performed in collaboration with LANL and UTK.
Understanding Microstructural Influences on Ductile Fracture Evolution in Metals (Collaboration with PSU)
Despite extensive research, ductile fracture prediction of metal alloys is still primarily empirical, with abstract damage accumulation applied largely as an engineering catch-all to estimate the remaining ductility in a material under various conditions, with little consideration given to the underlying microstructure and microstructural evolution taking place. The primary objective of this project is to uncover the role of multiaxial stress state on the development of dislocation structures leading to ductility exhaustion and eventual fracture nucleation in metals; this requires an understanding of the interplay of complex applied loading conditions, microstructure (grain misorientation and neighborhoods), and properties. This project is being performed in collaboration with faculty at PSU.