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Ductile deformation in alumina ceramics under quasi-static to dynamic contact impact

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journal contribution
posted on 18.11.2019, 10:57 by Robert Crookes, Benjamin Maerz, Houzheng Wu
Florescence spectroscopy and TEM has been used to study the ductile deformation of alumina ceramics underneath an impact contact. The contact was generated by a spherical tungsten carbide indenter under quasi-static, drop weight and ballistic loading conditions. In all circumstances, a ductile deformation region containing dislocations developed below each contact impression. The dislocation density distribution complies to the shear stress distribution predicted by the Hertzian contact model. Ballistic loading resulted in secondary material flow, giving a maximum dislocation density 5-10 times higher than that dictated by the Hertzian contact model. Quantification of dislocation density distribution allowed a critical shear stress for dislocation generation to be estimated. In this alumina ceramic, the critical shear stress is estimated as 2.55 ± 0.10 GPa. Cold work hardening and comminution under dynamic loading are discussed as possible mechanisms for the enhanced dislocation activity under dynamic impact.

Funding

Understanding and Improving Ceramic Armour Materials

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Materials

Published in

Materials & Design

Volume

187

Publisher

Elsevier BV

Version

VoR (Version of Record)

Rights holder

© Elsevier

Publisher statement

This is an Open Access Article. It is published by Elsevier under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date

13/11/2019

Publication date

2019-11-16

Copyright date

2019

ISSN

0261-3069

eISSN

0264-1275

Language

en

Depositor

Dr Houzheng Wu Deposit date: 17 November 2019

Article number

108360

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