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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 SiB 6 :B 4 C and B:B 4 C 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 SiB 6 Standard Development of z-factor Microanalysis Diffusion Zone and Region of Interest B 4 C Diffusion Zone SiB 6 B 6 O Diffusion Zone SiB 6 B 6 O 50 mm 15 mm TEM Sample STEM-EDS Map of B 4 C:B 6 O Diffusion Line Bulk Phase Quantification (at.%) Boron Carbon Oxygen Silicon B 4 C 85.7 ± 0.4 11.0 ± 0.4 1.2 ± 0.2 2.2 ± 0.3 B 6 O 86.8 ± 0.7 2.2 ± 1.1 10.4 ± 2.0 0.7 ± 0.3 Boron Carbon Oxygen Silicon B 4 C N/A N/A 0.4 ± 0.4 3.3 ± 0.6 B 6 O 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/nm 2 ) B 4 C Amorphization Band Y-doped B 6 O Grain Boundary Thermodynamic Evaluation of B 4 C:SiB 6 Diffusion Couple
