Crookes_1-s2.0-S0264127519307981-main.pdf (5.36 MB)
Ductile deformation in alumina ceramics under quasi-static to dynamic contact impact
journal contribution
posted on 2019-11-18, 10:57 authored by Robert Crookes, Benjamin Maerz, Houzheng WuFlorescence
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 & DesignVolume
187Publisher
Elsevier BVVersion
- VoR (Version of Record)
Rights holder
© ElsevierPublisher 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
2019-11-13Publication date
2019-11-16Copyright date
2019ISSN
0261-3069eISSN
0264-1275Publisher version
Language
- en