ADVANCED MATERIALS RESEARCH AT BROWN UNIVERSITY
As described in the White House’s June 2011 white paper, Materials Genome Initiative for Global Competitiveness, the development of advanced materials is crucial to fueling the nation’s manufacturing base and helping advance myriad technologies to address challenges in energy, health, and security. With its broad research enterprise that features close collaborations between simulation, analysis, and experiment, Brown University can provide a model for combining fundamental materials research with industry partnerships to create an innovation pipeline for materials development.
The research program in solid mechanics and materials science at Brown has contributed extensively to developing analytical, computational, and experimental approaches to materials design. Brown has developed and applied computer simulations of material behavior through finite element methods, discrete-dislocation modeling, molecular dynamics, ab-initio simulations, and a range of coupled multi-scale simulation methods. A range of experimental techniques unique to Brown complement our modeling capabilities. They include a multi-beam stress sensor for measuring stress evolution in thin films, techniques for fabricating specimens for in-situ TEM observations, interferometric displacement measurements, atomic-force microscopy for measuring surface interactions, and sensors to measure stresses exerted by biological cells.
Brown Engineering faculty collaborate extensively with industry, national labs, and other universities. Industrial partners include General Motors (through the General Motors Collaborative Research Laboratory in Computational Materials Research), GE Aviation, Medtronic, IBM, Yardney, Westinghouse, and Arcelor-Mittal. Collaborations with national labs include Oak Ridge, Argonne, Lawrence Livermore, and Sandia. Among our international partners are the Max Planck Institute, Institute of Metals Research of the Chinese Academy of Sciences, Institute for High-Performance Computing in Singapore, Korea Institute of Science and Technology, and Korea Institute of Materials and Machinery.
Current research interests of Brown Engineering faculty include:
Mechanics of nanoscale devices and structures studies the effects of stress in driving self-assembly, deformation, and evolution of nanoscale materials, as well as the structure-function relationships in nanomechanical and biomimetic devices. Research addresses the mechanical, optical, and chemical response of graphene, scission mechanisms in carbon nanotubes, the role of stress in controlling the morphology and composition of self-assembled quantum dots on strained surfaces, and the growth of mechanisms and properties of nanowires.
Mechanics of thin films and surfaces seeks to measure, model, and ultimately control stress and its effects in thin films and engineered surfaces. Applications include protective coatings, microelectronic components and packaging, engineered surfaces for catalysis, and nanoscale surface imprinting. Recent studies have addressed the mechanisms for generating stress during the growth of thin polycrystalline metallic, oxide, and diamond films, stress evolution and whisker growth mechanisms in lead-free Sn coatings for electronic applications, mechanics of stress, defects, and surface pattern formation induced by ion bombardment, nanoscale mechanisms of friction and deformation in contacting surfaces, and mechanics of nano-imprinting.
Mechanics of materials for energy storage has the goal of understanding the effects of stress on the electrochemical behavior and life of battery materials. Research focuses on the experimental characterization of the mechanical and electrochemical properties of electrode materials, atomistic simulations of Li transport and reactions in high-capacity anode materials, the measurement of properties of the solid-electrolyte interphase layers, the manufacture and testing of novel anode architectures, and modeling fracture in composite electrodes with complex microstructure.
Biomaterials and bio-physics seek to determine the role of stress and deformation in biological processes. Current research topics include bacterial propulsion mechanisms, multi-scale simulation and experimental characterization of cell damage caused by traumatic brain injuries, hierarchical structures in biological materials, and the mechanics of biopolymer networks, endocytosis, cell interactions with soft elastic nanoparticles, and cell mobility and adhesion.
Structural Materials include metals, ceramics, and composites used in automotive, aerospace, energy conversion, and power-plant applications. Current research includes multi-scale modeling of room and elevated temperature formability of lightweight Al and Mg alloys, experimental and computational studies of deformation mechanisms in emergent high-strength nanostructured and nano-twinned materials, modeling formability of steels, and fatigue behavior in alloys for biomedical applications.
Future areas of research interest include:
Computational design of multiphase alloys: Understanding the role of solutes on the behavior of these alloys is a critical step in developing a range of advanced materials. Recent advances at Brown in modeling quantitatively the influence of solutes on bonding (and their resulting effects on defect nucleation and motion) now enable quantitative predictions of the influence of solute chemistry on material behavior for the first time. Progress in nano-scale measurements (in particular quantitative mapping of strain fields using atomic force microscopy) also enables direct experimental verification of model predictions. Applying these techniques to study the influence of solutes on phase stability, dislocations; interfaces and grain boundaries; and crack nucleation and propagation are of particular interest.
Multiscale computational design of engineered coatings and surfaces: Managing or exploiting the effects of stress in thin films and surfaces is central to technologies ranging from microelectronic fabrication to nano-imprinting. Problems of particular interest include modeling and measuring stress effects on catalysis on patterned surfaces, computation of atomic scale surface structure in stressed crystals, modeling defects and stresses induced by ion bombardment of surfaces, predicting deposition stresses in polycrystalline alloy films, and developing and validating models that can help mitigate whisker growth in lead-free solder films for microelectronics.
Biomechanics of injury and recovery: Controlling the response of cells to stress is a critical factor in mitigating traumatic brain injury (TBI), wound healing, and tissue growth. Novel modeling and experimental capabilities at Brown offer an opportunity to establish quantitative predictive models that would guide impact and blast mitigation strategies, help develop optimal therapies for the treatment of TBI, and provide a predictive framework for tissue engineering. Cell-level modeling, guided and calibrated by in-situ experimental observations, would address the migration, healing, and growth processes in damaged and un-damaged cells, with a view to constructing models capable of predicting the post-healed state of tissue after injury.
Biomechanics of cell interactions with 1-D and 2-D nanomaterials: Nanomaterials such as carbon nanotubes, nanowires, nanofibers, and graphene have potential applications for next generation microchips, composites, barrier coatings, biosensors, and drug delivery. These technologies are projected to release thousands of tons of nanomaterials into the atmosphere in the coming decades. There is thus an urgent need to understand the hazards of nanomaterials to health. Multiscale modeling and experimental capabilities at Brown offer opportunities to identify the fundamental mechanisms and pathways for cell-nanomaterials interactions that are relevant for cellular uptake, toxicity, and induction of diseases. Insights from these studies would guide development of strategies to mitigate the risks of nanomaterials.
Scalable algorithms for automated computational materials design: Advances in the accuracy and reliability of computer simulation of material behavior will ultimately enable automated combinatorial materials design. There is a need to develop automated hierarchical computational tools to calculate material properties of interest in particular design applications. There are opportunities to combine material modeling techniques available at Brown with adaptable, scalable algorithms and data structures that enable automated materials discovery.