This goal of this project is to understand and design high strength, ductile amorphous-crystalline nanolaminates. This will be accomplished through an understanding of the length-scale effects on the deformation behavior of laminated amorphous and nanocrystalline layers, and the interplay between dislocations and the amorphous-nanocrystalline (a-c) interfaces. The nanolaminates are based on the Cu-Zr system and fabricated by the alternative deposition of Cu and Zr layers followed by solid-state amorphization. The thickness of the amorphous layer is controllable and the chemistry of the amorphous phase, as well as the a-c interface, can also be tuned by selective alloying with Ni and Al, for example. The microstructure, chemical and defect distributions in the nanolaminates will be characterized using advanced instruments such as Cs-corrected high-resolution TEM, atom probe tomography, X-ray scattering, and small-angle neutron scattering. Deformation behavior will be investigated by conventional tensile tests on free-standing foil samples and a micro-compression technique. Microscale specimens (micro-pillars) with the a-c interfaces aligned in controlled orientations will be fabricated using focused ion beam machining. In situ straining experiments will enable observation of dislocation-interface interactions using high-resolution TEM. High-temperature experiments using a nanoindentation system will be performed. Preliminary molecular dynamic simulations on the deformation of nanolaminates are proposed, with special emphasis on the interaction between dislocations and the a-c interfaces.

NON-TECHNICAL SUMMARY:

Understanding the deformation of nanolaminates at the atomistic level represents a giant step towards a understanding the interactions between dislocations and interfaces at the nanometer level. This ability can further aid in the design and reliable application of multilayered devices, e.g. structures that are widely used in various technological fields, such as advanced electronic devices, micro- and nano-scale MEM systems, biosensors, magnetics, and thermal barrier coatings. In addition, the study of dislocation interactions with the amorphous-crystalline interface can shed light on the mechanical response of grain boundaries. This project will advance and enhance the research and education activities at UT by offering excellent opportunities to undergraduate and graduate students. Educational materials will be developed and distributed through a new graduate-level class for students pursuing advanced degrees in MSE with a concentration on nanomaterials. To recruit and enhance women and minority participation into this program, the PI will work with the College of Engineering's (CoE) representatives of the National Consortium for Graduate Education for the Minorities in Engineering and Science, and the CoE Pipeline Engineering Diversity Program. The PI is working with the CoE's Tennessee Louis Stokes Alliance for Minority Participation to mentor undergraduate students, foster interest in research and develop potential applicants for summer-research studies.

Agency
National Science Foundation (NSF)
Institute
Division of Materials Research (DMR)
Type
Standard Grant (Standard)
Application #
0905979
Program Officer
Diana Farkas
Project Start
Project End
Budget Start
2009-10-01
Budget End
2014-09-30
Support Year
Fiscal Year
2009
Total Cost
$315,838
Indirect Cost
Name
University of Tennessee Knoxville
Department
Type
DUNS #
City
Knoxville
State
TN
Country
United States
Zip Code
37996