Surface engineering alumina armour ceramics with laser shock peening

Pratik Shukla; Stuart  Robertson; Houzheng Wu; Abhishek  Telang; Michael  Kattoura; Subhasisa Nath; Seetha Ramaiya  Mannava; Vijay  Vasudevan; Jonathan Lawrence

doi:10.1016/j.matdes.2017.08.066

Surface engineering alumina armour ceramics with laser shock peening

Pratik Shukla, Stuart Robertson , Houzheng Wu, Abhishek Telang , Michael Kattoura, Subhasisa Nath, Seetha Ramaiya Mannava, Vijay Vasudevan , Jonathan Lawrence

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Abstract

Laser shock peening (LSP) of Al2O3 armour ceramics is reported for the first-time. A 10 J, 8 ns, pulsed Nd:YAG laser with a 532 nm wavelength was employed. The hardness, KIc, fracture morphology, topography, surface residual stresses and microstructures were investigated. The results showed an increase in the surface hardness by 10% which was confirmed by a reduction in Vickers indentations size by 5%. The respective flaw sizes of the Vickers indentations were also reduced (10.5%) and inherently increased the KIc (12%). Residual stress state by X-ray diffraction method showed an average stress of − 64 MPa after LSP, whilst the untreated surface stress measured + 219 MPa. Further verification with the fluorescence method revealed surface relaxation with a maximum compressive stress of − 172 MPa induced after LSP within the Al2O3 armour ceramic. These findings are attributed to a microstructural refinement, grain size reduction and an induction of compressive stress that was relaxing the top/near surface layer (post LSP) from the pre-existing tensile stresses. Further process refinement/optimization will provide better control of the surface properties and will act as a strengthening technique to improve the performance of armour ceramics to stop bullets for a longer period of time and protect the end-users.

Original language	English
Pages (from-to)	523-538
Number of pages	16
Journal	Materials and Design
Volume	134
Early online date	1 Sept 2017
DOIs	https://doi.org/10.1016/j.matdes.2017.08.066
Publication status	Published - 15 Nov 2017

Bibliographical note

Publisher Statement: NOTICE: this is the author’s version of a work that was accepted for publication in Materials and Design. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Materials and Design, [134, (2017)] DOI: 10.1016/j.matdes.2017.08.066

© 2017, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

Keywords

LSP
Ceramics
Al2O3
Hardness
KIc fracture toughness
residual stress
Microstructure

Access to Document

10.1016/j.matdes.2017.08.066

Post-PrintAccepted author manuscript, 4 MBLicence: CC BY-NC-ND

Cite this

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title = "Surface engineering alumina armour ceramics with laser shock peening",

abstract = "Laser shock peening (LSP) of Al2O3 armour ceramics is reported for the first-time. A 10 J, 8 ns, pulsed Nd:YAG laser with a 532 nm wavelength was employed. The hardness, KIc, fracture morphology, topography, surface residual stresses and microstructures were investigated. The results showed an increase in the surface hardness by 10% which was confirmed by a reduction in Vickers indentations size by 5%. The respective flaw sizes of the Vickers indentations were also reduced (10.5%) and inherently increased the KIc (12%). Residual stress state by X-ray diffraction method showed an average stress of − 64 MPa after LSP, whilst the untreated surface stress measured + 219 MPa. Further verification with the fluorescence method revealed surface relaxation with a maximum compressive stress of − 172 MPa induced after LSP within the Al2O3 armour ceramic. These findings are attributed to a microstructural refinement, grain size reduction and an induction of compressive stress that was relaxing the top/near surface layer (post LSP) from the pre-existing tensile stresses. Further process refinement/optimization will provide better control of the surface properties and will act as a strengthening technique to improve the performance of armour ceramics to stop bullets for a longer period of time and protect the end-users.",

keywords = "LSP, Ceramics, Al2O3, Hardness, KIc fracture toughness, residual stress, Microstructure",

author = "Pratik Shukla and Stuart Robertson and Houzheng Wu and Abhishek Telang and Michael Kattoura and Subhasisa Nath and Mannava, {Seetha Ramaiya} and Vijay Vasudevan and Jonathan Lawrence",

note = "Publisher Statement: NOTICE: this is the author{\textquoteright}s version of a work that was accepted for publication in Materials and Design. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Materials and Design, [134, (2017)] DOI: 10.1016/j.matdes.2017.08.066 {\textcopyright} 2017, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/",

year = "2017",

month = nov,

day = "15",

doi = "10.1016/j.matdes.2017.08.066",

language = "English",

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pages = "523--538",

journal = "Materials and Design",

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TY - JOUR

T1 - Surface engineering alumina armour ceramics with laser shock peening

AU - Shukla, Pratik

AU - Robertson , Stuart

AU - Wu, Houzheng

AU - Telang , Abhishek

AU - Kattoura, Michael

AU - Nath, Subhasisa

AU - Mannava, Seetha Ramaiya

AU - Vasudevan , Vijay

AU - Lawrence, Jonathan

N1 - Publisher Statement: NOTICE: this is the author’s version of a work that was accepted for publication in Materials and Design. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Materials and Design, [134, (2017)] DOI: 10.1016/j.matdes.2017.08.066 © 2017, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

PY - 2017/11/15

Y1 - 2017/11/15

N2 - Laser shock peening (LSP) of Al2O3 armour ceramics is reported for the first-time. A 10 J, 8 ns, pulsed Nd:YAG laser with a 532 nm wavelength was employed. The hardness, KIc, fracture morphology, topography, surface residual stresses and microstructures were investigated. The results showed an increase in the surface hardness by 10% which was confirmed by a reduction in Vickers indentations size by 5%. The respective flaw sizes of the Vickers indentations were also reduced (10.5%) and inherently increased the KIc (12%). Residual stress state by X-ray diffraction method showed an average stress of − 64 MPa after LSP, whilst the untreated surface stress measured + 219 MPa. Further verification with the fluorescence method revealed surface relaxation with a maximum compressive stress of − 172 MPa induced after LSP within the Al2O3 armour ceramic. These findings are attributed to a microstructural refinement, grain size reduction and an induction of compressive stress that was relaxing the top/near surface layer (post LSP) from the pre-existing tensile stresses. Further process refinement/optimization will provide better control of the surface properties and will act as a strengthening technique to improve the performance of armour ceramics to stop bullets for a longer period of time and protect the end-users.

AB - Laser shock peening (LSP) of Al2O3 armour ceramics is reported for the first-time. A 10 J, 8 ns, pulsed Nd:YAG laser with a 532 nm wavelength was employed. The hardness, KIc, fracture morphology, topography, surface residual stresses and microstructures were investigated. The results showed an increase in the surface hardness by 10% which was confirmed by a reduction in Vickers indentations size by 5%. The respective flaw sizes of the Vickers indentations were also reduced (10.5%) and inherently increased the KIc (12%). Residual stress state by X-ray diffraction method showed an average stress of − 64 MPa after LSP, whilst the untreated surface stress measured + 219 MPa. Further verification with the fluorescence method revealed surface relaxation with a maximum compressive stress of − 172 MPa induced after LSP within the Al2O3 armour ceramic. These findings are attributed to a microstructural refinement, grain size reduction and an induction of compressive stress that was relaxing the top/near surface layer (post LSP) from the pre-existing tensile stresses. Further process refinement/optimization will provide better control of the surface properties and will act as a strengthening technique to improve the performance of armour ceramics to stop bullets for a longer period of time and protect the end-users.

KW - LSP

KW - Ceramics

KW - Al2O3

KW - Hardness

KW - KIc fracture toughness

KW - residual stress

KW - Microstructure

UR - http://www.mendeley.com/research/surface-engineering-alumina-armour-ceramics-laser-shock-peening-enhance-hardness-fracture-toughness

U2 - 10.1016/j.matdes.2017.08.066

DO - 10.1016/j.matdes.2017.08.066

M3 - Article

SN - 0261-3069

VL - 134

SP - 523

EP - 538

JO - Materials and Design

JF - Materials and Design

ER -

Surface engineering alumina armour ceramics with laser shock peening

Abstract

Bibliographical note

Keywords

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EPSRC Laser Loan Pool: Science & Technology Facilities Council (STFC) Rutherford Appleton Laboratory - Laser Shock Peening of Advance Ceramics and Cermets Applicable for Cutting Tools

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Surface engineering alumina armour ceramics with laser shock peening

Abstract

Bibliographical note

Keywords

Access to Document

Other files and links

Fingerprint

Projects

EPSRC Laser Loan Pool: Science & Technology Facilities Council (STFC) Rutherford Appleton Laboratory - Laser Shock Peening of Advance Ceramics and Cermets Applicable for Cutting Tools

Cite this