| NSF Org: |
CMMI Division of Civil, Mechanical, and Manufacturing Innovation |
| Recipient: |
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| Initial Amendment Date: | August 16, 2013 |
| Latest Amendment Date: | April 21, 2014 |
| Award Number: | 1301193 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Alexis Lewis
alewis@nsf.gov (703)292-2624 CMMI Division of Civil, Mechanical, and Manufacturing Innovation ENG Directorate for Engineering |
| Start Date: | September 1, 2013 |
| End Date: | February 28, 2017 (Estimated) |
| Total Intended Award Amount: | $324,274.00 |
| Total Awarded Amount to Date: | $329,274.00 |
| Funds Obligated to Date: |
FY 2014 = $5,000.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
2601 WOLF VILLAGE WAY RALEIGH NC US 27695-0001 (919)515-2444 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
NC US 27695-7906 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | MATERIALS AND SURFACE ENG |
| Primary Program Source: |
01001415DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.041 |
ABSTRACT
This research is about the correlation between the size effects of silicon nanowires on elasticity, fracture, and their brittle to ductile transition.. In-situ scanning/transmission electron microscopy resonance and tensile testing on the same single NWs will be conducted to measure the elastic behavior. A statistical, Weibull-type, probability model will be employed to analyze the fracture data and identify fracture origins with the assistance of real-time and post-mortem microscopy analyses. In-situ thermomechanical testing done in-situ, in a Transmission Electron Microscope using a novel microfabricated testing stage will be used to probe the brittle to ductile transition.
If successful, the proposed research has potential to improve flexible and stretchable electronics, improve energy conversion and storage. It is anticipated that the experimental results will be used in a collaborative way to develop atomistic simulations that will pin down the mundamental mechnisms of nanoscale elasticity, fracture and brittle to ductile transition. In addition, the novel experimental tools and methods developed in this project (e.g., the microfabricated thermomechanical testing stage) can be used to understand the properties of a broad range of nanostructures. From a teaching perspective, this work will be: 1) integrated into undergraduate and graduate courses that PI offers at NCSU (including a NSF supported undergraduate nanotechnology laboratory course), and web-based dissemination of the new course module; 2) used for training of graduate and undergraduate students for multidisciplinary research with involvement of women and underrepresented minorities; 3) used for collaboration with the Engineering Place program at North Carolina State University to develop an interactive demonstration module and present it to K-12 students.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This grant (Experimental Investigation of Fundamental Mechanical Behavior of Silicon Nanowires) has resulted in significant advance in the instrumentation capabilities for nanomechanical testing. Microelectromechanical system (MEMS) has been widely used for nanomechancial testing of nanostructures such as nanowires and nanotubes. As an outcome of this project, for the first time we have developed a MEMS testing stage that can perform thermomechanical testing of individual nanowires inside. In addition, we have measured and analyzed mechanical behaviors of Si nanowires including elasticity, fracture and brittle to ductile transition. We have obtained novel insights into the competition between surface dislocation nucleation and surface crack nucleation as a function of temperature and convincingly showed the brittle to ductile transition in Si nanowires based on several evidences including stress-strain curve, activation volume and postmortem TEM images where dislocations were directly observed.
The PI has presented the findings in journal publications and conference presentations. For example, his group published several journal articles on development of the MEMS devices and mechanical properties of several semiconductor nanowires. In particular, the PI has written three invited review articles on different aspects on experimental mechanics of nanowires - Y. Zhu, “Mechanics of Crystalline Nanowires: An Experimental Perspective”, Applied Mechanics Reviews 69 (1), 010802 (2017); Y. Zhu, “In-situ Nanomechanical Testing of Crystalline Nanowires in Electron Microscopes”, JOM 68 (1), 84-93 (2016); Y. Zhu and T.-H. Chang, “A Review of Microelectromechanical Systems for Nanoscale Mechanical Characterization”, Journal of Micromechanics and Microengineering 25, 093001 (2015). This grant has partly supported three graduate research assistants at PhD levels and four undergraduate research assistants, one of which is an African American female student. Materials coming out of this grant have been adopted in a graduate course and in outreach activities such as Nanodays at North Carolina State University.
Last Modified: 05/10/2017
Modified by: Yong Zhu
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