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Title: Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.

Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, deform, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle deformation and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental mechanisms responsible for plastic deformation/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containing numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic deformation and fracture without fragmentation. Dislocation nucleation/motion, significant plastic deformation, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. As a result, the identified deformation mechanisms provide insight into feedstock designmore » for AD.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND-2015-7094J
Journal ID: ISSN 1059-9630; 603168
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Thermal Spray Technology
Additional Journal Information:
Journal Volume: 25; Journal Issue: 1-2; Journal ID: ISSN 1059-9630
Publisher:
Springer
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; alumina; modeling; nanoindentation
OSTI Identifier:
1237699

Sarobol, Pylin, Chandross, Michael E., Carroll, Jay D., Mook, William M., Bufford, Daniel Charles, Boyce, Brad L., Hattar, Khalid Mikhiel, Kotula, Paul G., and Hall, Aaron Christopher. Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.. United States: N. p., Web. doi:10.1007/s11666-015-0295-2.
Sarobol, Pylin, Chandross, Michael E., Carroll, Jay D., Mook, William M., Bufford, Daniel Charles, Boyce, Brad L., Hattar, Khalid Mikhiel, Kotula, Paul G., & Hall, Aaron Christopher. Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.. United States. doi:10.1007/s11666-015-0295-2.
Sarobol, Pylin, Chandross, Michael E., Carroll, Jay D., Mook, William M., Bufford, Daniel Charles, Boyce, Brad L., Hattar, Khalid Mikhiel, Kotula, Paul G., and Hall, Aaron Christopher. 2015. "Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.". United States. doi:10.1007/s11666-015-0295-2. https://www.osti.gov/servlets/purl/1237699.
@article{osti_1237699,
title = {Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.},
author = {Sarobol, Pylin and Chandross, Michael E. and Carroll, Jay D. and Mook, William M. and Bufford, Daniel Charles and Boyce, Brad L. and Hattar, Khalid Mikhiel and Kotula, Paul G. and Hall, Aaron Christopher},
abstractNote = {Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, deform, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle deformation and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental mechanisms responsible for plastic deformation/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containing numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic deformation and fracture without fragmentation. Dislocation nucleation/motion, significant plastic deformation, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. As a result, the identified deformation mechanisms provide insight into feedstock design for AD.},
doi = {10.1007/s11666-015-0295-2},
journal = {Journal of Thermal Spray Technology},
number = 1-2,
volume = 25,
place = {United States},
year = {2015},
month = {9}
}