Research home
We strive to understand the relationship between the mechanical properties and the microstructure of materials in detail by a combination of synthesis, mechanical property measurements, microstructural examination, and modelling:
Synthesis and fabrication of films and structures with extremely good control of composition, microstructure and geometry is a prerequisite for the rest of our work. As a result we have developed a high level of expertise in this area. We can prepare films by physical deposition methods in our group and use the Cornell Nanofabrication Facility for chemical vapor depostion and nanofabriaction techniques.
A major focus of our research is on high resolution mechanical properties measurements on the nanometer and micrometer dimensional scales. We have developed particular expertise in the use of substrate curvature methods for determining stresses in films, nanoindentation methods for determining hardness, stiffness and time-dependent deformation characteristics, and x-ray measurements of elastic strains. We continue to develop new methods and to improve existing ones and have a collection of techniques availiable "in house." We can offer extensive consulting, collaboration, and advice in this area as well.
We use state of the art methods for examining the microstructure of our samples. Our emphasis is on grain and interface structure, orientation, dislocations, topography and local chemistry. We use a wide array of microscopies (TEM, FIB, EBSD, AFM...), and spectroscopies (RBS, SIMS, EELS...), as well as x-ray diffraction methods. This work is enabled by our collaborators and the multi-user facilities at the Cornell Center for Materials Research, the Cornell High Energy Synchrotron Source, the Max-Planck-Institut für Metallforschung, and elsewhere.
Finally, since mechanical properties are determined by the ensemble behavior of many microstructural features, we develop models to relate mechanical behavior across length scales. This work is highly collaborative and we are working with a number of experts at many different institutions. This work includes empirical models, continuum mechanics, finite and boundary elements, and discrete dislocation dynamics.
