Award Abstract # 2417298
Understanding the Role of Residual Stress Gradients on Plastic Strain Recovery in Nanocrystalline Thin Films

NSF Org: CMMI
Division of Civil, Mechanical, and Manufacturing Innovation
Recipient: UNIVERSITY OF NORTH TEXAS
Initial Amendment Date: February 20, 2024
Latest Amendment Date: March 18, 2024
Award Number: 2417298
Award Instrument: Standard Grant
Program Manager: Siddiq Qidwai
sqidwai@nsf.gov
 (703)292-2211
CMMI
 Division of Civil, Mechanical, and Manufacturing Innovation
ENG
 Directorate for Engineering
Start Date: October 1, 2023
End Date: November 30, 2025 (Estimated)
Total Intended Award Amount: $482,511.00
Total Awarded Amount to Date: $413,161.00
Funds Obligated to Date: FY 2022 = $413,161.00
History of Investigator:
  • Yufeng Zheng (Principal Investigator)
    Yufeng.Zheng@unt.edu
  • Leslie Mushongera (Former Principal Investigator)
Recipient Sponsored Research Office: University of North Texas
1112 DALLAS DR STE 4000
DENTON
TX  US  76205-1132
(940)565-3940
Sponsor Congressional District: 13
Primary Place of Performance: University of North Texas
1112 DALLAS DR STE 4000
DENTON
TX  US  76205-1132
Primary Place of Performance
Congressional District:
13
Unique Entity Identifier (UEI): G47WN1XZNWX9
Parent UEI:
NSF Program(s): Mechanics of Materials and Str
Primary Program Source: 01002223DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 9102, 9150, 9161, 013E, 024E, 027E, 022E
Program Element Code(s): 163000
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.041

ABSTRACT

This award supports research to identify the microscopic mechanisms governing plastic strain recovery in pure nanocrystalline metal thin films. This project will implement an integrated experimental and modeling strategy to address this objective. The identification of the mechanisms governing plastic strain recovery will raise the possibility of designing metal components that may recover after being deformed or dented. This fundamental knowledge will be used to develop predictive tools, which will facilitate the accurate prognosis of life to mitigate premature failures. There is a wide range of applications such as gas turbines and tribological coatings among others that can benefit from these developments. In addition, the project will provide an integrated training platform for the future and diverse workforce via the education of graduate and undergraduate students in the areas of computational mechanics and microscopy. A particularly interesting ativity in this regard is the partnership with a local community college, whose students will be able to apply for 8-week long research internships.

The deformation behavior of nanocrystalline metals substantially differs from that of coarse-grained metals. One such unique behavior is the ability of nanocrystalline metals to recover plastic strain. This phenomenon is quite unusual since plastic deformation in metals is considered permanent after unloading. The critical micromechanical driving forces are not clear however and remain a subject of conjecture. As a result, a microstructure-sensitive predictive modeling framework also remains elusive. Specific objectives of this work are to: (1) identify the influence of mismatch in elastic response of nano-sized grains on plastic strain recovery; (2) elucidate the influence of texture on the residual stresses; (3) identify the connection between grain boundary sliding and strain compatibility; and (4) identify the influence of grain boundary sliding on the residual stress gradients. An integrated experimental-modeling plan is put in place to achieve these objectives that includes extensive in-situ testing and characterization using advanced microscopy techniques, such as the scanning transmission electron microscopy, and sophisticated elastoplastic phase field modeling method.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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