Accession Number:

ADA623362

Title:

Sample Size Induced Brittle-to-Ductile Transition of Single-Crystal Aluminum Nitride

Descriptive Note:

Journal article

Corporate Author:

ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE

Personal Author(s):

• Guo, J. J.
• Reddy, K. M.
• Hirata, A.
• Fujita, T.
• Gazonas, G. A.
• McCauley, J. W.
• Chen, M. W.

Report Date:

2015-08-01

Pagination or Media Count:

14.0

Abstract:

Ceramics are known to be mechanically hard, chemically inert and electrically insulating for many important applications.However, they usually suffer from brittleness and have moderate strength that strongly depends on their microscopic structure.In this study, we report a size induced brittle-to-ductile transition in single-crystal aluminum nitride AlN. When thespecimen diameters are smaller than 3--4 um, AlN micropillars show metal-like plastic flow under room-temperatureuniaxial compression. The unprecedented plastic strain of 5--10 together with the ultrahigh strength of 6.7 GPa has neverbeen achieved before. Transmission electron microscopy demonstrates that dislocations play a dominant role in the plasticityof the micro-sized AlN.

Descriptors:

• *ALUMINUM NITRIDES
• *SINGLE CRYSTALS
• BRITTLENESS
• CERAMIC MATERIALS
• DISLOCATIONS
• PLASTIC FLOW
• RAMAN SPECTROSCOPY
• REPRINTS
• ROOM TEMPERATURE
• STRENGTH(GENERAL)
• TRANSMISSION ELECTRON MICROSCOPY

Subject Categories:

• Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE