| NSF Org: |
CMMI Division of Civil, Mechanical, and Manufacturing Innovation |
| Recipient: |
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| Initial Amendment Date: | July 14, 2017 |
| Latest Amendment Date: | July 29, 2019 |
| Award Number: | 1727428 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Lucy T. Zhang
CMMI Division of Civil, Mechanical, and Manufacturing Innovation ENG Directorate for Engineering |
| Start Date: | August 1, 2017 |
| End Date: | July 31, 2022 (Estimated) |
| Total Intended Award Amount: | $476,409.00 |
| Total Awarded Amount to Date: | $481,279.00 |
| Funds Obligated to Date: |
FY 2019 = $4,870.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
1664 N VIRGINIA ST # 285 RENO NV US 89557-0001 (775)784-4040 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1664 N. Virginia Street Reno NV US 89557-0001 |
| 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): |
Mechanics of Materials and Str, Special Initiatives |
| Primary Program Source: |
01001920DB 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
Strength refers to a material's ability to withstand failure or yield, while ductility is its ability to permanently deform without fracture. Many important engineering applications require high strength and yet ductile materials, such as in cutting tools, body armor for soldiers, and manufacturing process. One promising candidate is boron carbide, a so-called superhard ceramic names so because of its strength; however, it has low ductility. In poly-crystalline materials, the strength and ductility are commonly associated with microstructural features at the lower length scales (micrometers and below). There is a significant knowledge gap regarding the impact of microstructure on the strength and ductility of superhard ceramics. This project is directed towards the study of the physical mechanisms that underlie the relationships between microstructure, and strength and ductility of boron carbide based materials using computational modeling and simulations. The project will also establish design principles based on the knowledge gained for the development of new boron carbide based materials with enhanced strength and ductility. The design strategies will be extendable to a variety of other superhard materials, such as borides, carbides, and diamond. The research will be integrated into both undergraduate and graduate education, as well as outreach activities for local high school students. The research project will also target the participation of women and under-represented minority students in science, technology, engineering, and math disciplines.
The research objective of this project is to illustrate how microstructure determines the deformation and mechanical processes in boron carbide based materials. The research team will apply a multiscale approach coupling atomistic modeling and the mesoscale phase field method to (1) investigate the impact of grain boundaries on mechanical properties, deformation, and failure mechanisms of boron carbide; and (2) establish the design principles to enhance the strength and ductility of boron carbide through engineering of grain boundary properties with microalloying. The research will make original contributions in elucidating the origins of the strength and ductility of polycrystalline superhard ceramics under realistic conditions. The materials design principles will be applied to inspire experimental synthesis of stronger and tougher boron carbide based materials for commercial applications.
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.
In this project, the PI and Co-PI developed a multiscale approach coupling density functional theory, atomistic modeling, and the mesoscale phase field method. Then we applied this approach to illustrate the impact of grain boundaries on mechanical properties, deformation, and failure mechanisms of boron carbide, a promising superhard material with a low density and excellent impact resistance. Through the research activities in this project, we first identified that the major failure mechanism of polycrystalline boron carbide involves the local amorphization along grain boundaries and the penetration of amorphization into interior grains. Then we established a couple of design principles to enhance the ductility of boron carbide through the engineering of grain boundary properties. The first design principle is to decrease the grain size to nanoscale grains to promote the sliding between grains and suppress the penetration of amorphization into interior grains. The second approach is to increase the boron concentration in boron carbide so that amorphization nucleation is delayed. The third approach is to micro-alloy silicon into boron carbide so that the grain boundary properties are modified and the local amorphization is suppressed. With the support of this award, the PI and Co-PI have published about thirty-five papers in decent scientific journals.
Enhancing the toughness and ductility of superhard boron carbide can significantly extend its engineering applications to extreme environments such as high temperature, high pressure, and highly corrosive conditions. The materials design principles established in this project provide the fundamental theoretical basis for future experimental synthesis and characterization of tougher boron carbide based materials. Through this project, the multiscale computational framework has been developed and can be effectively extended to a variety of other important superhard materials such as carbide, boride, and diamond.
The research outcomes from this project have been integrated into undergraduate-level and graduate-level courses. In this project, we have trained next-generation scientists, engineers, and skilled technical workers within the field of mechanics of materials and structures. Particularly, several minority students in science, technology, engineering, and math disciplines have participated in this research project and trained well for their future academic and industrial careers. With the support of this award, two graduate students have obtained Ph.D degree and one graduate student has obtained MS degree from University of Nevada, Reno.
Last Modified: 08/07/2022
Modified by: Qi An
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