A selection of videos produced by IMR Group members. The videos (and their descriptions) are available in the gallery.
To meet the challenges we face in energy production and usage, transportation, communications, security etc., requires that we synthesize and process new materials whose properties are orders of magnitude better than current materials and move them from laboratory scale to applications more rapidly. Success requires a transition from empirical-based to mechanistic-based approaches. The group research efforts are centered on discovery and understanding of the basic processes and mechanisms that govern the macroscopic response of materials intended for use in extreme environments - strain rate, temperature, corrosive and radiation. This knowledge is central to driving us towards a mechanistic-based approach for materials design and application.
Current efforts in the group focus on uncovering the mechanisms of strain transfer across interfaces as a function of interface type, temperature and strain rate; the interaction of dislocations with precipitates and radiation produced defects as a function of temperature and strain rate; the processes governing thermal and stress driven grain growth in nano-grained and ultra-fine grained metals; the mechanisms of hydrogen embrittlement of pipeline steels and weldments with the goal of enabling the design of steels with lower susceptibility to hydrogen attack; and the surface processes controlling uptake and release of hydrogen from light-weight complex metal hydrides.
To discover deformation processes and mechanisms and how dislocations interact with obstacles, we combine macroscopic mechanical tests and post-loading characterization with time-resolved deformation experiments in the transmission electron microscope. This latter approach provides direct insight as to how dislocation reactions and interactions evolve with increasing strain. To further enhance our ability to discover controlling mechanisms, we are exploring use of tomographic reconstruction methods to obtain from two-dimensional electron micrographs a three-dimensional image that can be manipulated to enable viewing from any vantage point. Ultimately, we seek to combine both approaches, using time-resolved experiments to provide insight on reaction pathways and tomographic reconstruction to provide three-dimensional snapshots during the evolution process.
The funds for these projects are provided by DOE EERE, DOE BES, DOE NE, DOE NNSA, Los Alamos National Laboratory, Oak Ridge National Laboratory EFRC Center for Defect Physics and ExxonMobil.
Current efforts in the group focus on uncovering the mechanisms of strain transfer across interfaces as a function of interface type, temperature and strain rate; the interaction of dislocations with precipitates and radiation produced defects as a function of temperature and strain rate; the processes governing thermal and stress driven grain growth in nano-grained and ultra-fine grained metals; the mechanisms of hydrogen embrittlement of pipeline steels and weldments with the goal of enabling the design of steels with lower susceptibility to hydrogen attack; and the surface processes controlling uptake and release of hydrogen from light-weight complex metal hydrides.
To discover deformation processes and mechanisms and how dislocations interact with obstacles, we combine macroscopic mechanical tests and post-loading characterization with time-resolved deformation experiments in the transmission electron microscope. This latter approach provides direct insight as to how dislocation reactions and interactions evolve with increasing strain. To further enhance our ability to discover controlling mechanisms, we are exploring use of tomographic reconstruction methods to obtain from two-dimensional electron micrographs a three-dimensional image that can be manipulated to enable viewing from any vantage point. Ultimately, we seek to combine both approaches, using time-resolved experiments to provide insight on reaction pathways and tomographic reconstruction to provide three-dimensional snapshots during the evolution process.
The funds for these projects are provided by DOE EERE, DOE BES, DOE NE, DOE NNSA, Los Alamos National Laboratory, Oak Ridge National Laboratory EFRC Center for Defect Physics and ExxonMobil.