microanalysis and atomic-resolution characterization of boron … · 2018-10-18 · validation of...
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Enterprise for Multi-scale Research of Materials
Microanalysis and Atomic-Resolution
Characterization of Boron-rich Ceramics
Martin P. Harmer & Christopher J. Marvel
Lehigh University
How We Fit Technical Approach Key Accomplishments
Key Goals
Major Results
Impact
Transitions to ARL, within
CMRG and to other CMRGs
UNCLASSIFIED
UNCLASSIFIED
Sample Characterization – ac-STEM
(JEOL ARM200-CF)
Sample Preparation - Focused Ion Beam
(FEI Scios)
Aberration-corrected Scanning Transmission Electron Microscopy
Interfacial Design of Armor Ceramics to Enhance Mechanical Performance
• Engineer grain boundary complexions in armor ceramics
• Develop and implement light element microanalysis via z-factor quantification
• Study SiB6:B4C and B:B4C diffusion couples to evaluate bulk and grain boundary
thermodynamics
1. Design microstructures and interfaces (e.g. grain boundaries)
to modify fracture mechanisms
2. Develop and implement quantitative microanalysis of light
elements (e.g. B, C, and O)
1. All raw data is supplied to ARL and CMRG collaborators
2. New techniques and z-factor approach/computer code can be
shared with CMRG collaborators
Final Equations
Validation of z-factor Microanalysis using SiB6 Standard
Development of z-factor Microanalysis
Diffusion Zone and Region of Interest
B4C Diffusion Zone SiB6B6O
Diffusion Zone SiB6B6O
50 mm
15 mm
TEM Sample
STEM-EDS Map of B4C:B6O Diffusion Line
Bulk Phase Quantification
(at.%)
Boron Carbon Oxygen Silicon
B4C 85.7 ± 0.4 11.0 ± 0.4 1.2 ± 0.2 2.2 ± 0.3
B6O 86.8 ± 0.7 2.2 ± 1.1 10.4 ± 2.0 0.7 ± 0.3
Boron Carbon Oxygen Silicon
B4C N/A N/A 0.4 ± 0.4 3.3 ± 0.6
B6O N/A 1.1 ± 3.2 N/A 3.7 ± 1.0
1. Interfacial design and new microanalysis techniques can be used to
develop other materials relevant to ARL and the CMRG
2. Atomic-resolution capabilities can be applied to study local chemistry
differences of amorphization bands or planar defects
• z-factor microanalysis includes a built-in absorption correction which
is necessary to quantify EDS results
• Elemental mapping and grain boundary excess coverage
measurements are possible
Grain Boundary Quantification
(atoms/nm2)
B4C Amorphization Band Y-doped B6O Grain Boundary
Thermodynamic Evaluation of B4C:SiB6 Diffusion Couple
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