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

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.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 2015
Accession Number
ADA623362

Entities

People

  • A. Hirata
  • George A. Gazonas
  • J. J. Guo
  • J. W. Mccauley
  • K. M. Reddy
  • Mingwei Chen
  • T. Fujita

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aluminum Nitrides
  • Crystal Structure
  • Crystals
  • Diameters
  • Diffraction
  • Electron Microscopy
  • Failure Mode And Effect Analysis
  • Mechanical Properties
  • Mechanical Working
  • Metals
  • Microscopy
  • Plastic Flow
  • Plastic Properties
  • Raman Spectroscopy
  • Single Crystals
  • Transitions
  • Transmission Electron Microscopy

Fields of Study

  • Materials science
  • Physics

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Nanocomposite Materials Science
  • Thin Film Deposition Science.

Technology Areas

  • Microelectronics
  • Microelectronics - Graphene