Chapter 5
Dry Laser Peening: Ultrashort Pulsed
Laser Peening Without Sacrificial
Overlay Under Atmospheric Conditions
Tomokazu Sano
Abstract Laser peening, or laser shock peening, is a surface modification technique
using a laser-driven shock wave to improve mechanical properties of solids such as
hardness, residual stress, fatigue properties, and corrosion resistance. An ultrashort
pulsed laser-driven shock compression of solids enables peening without sacrificial
overlay under atmospheric conditions, which is called Dry Laser Peening (DryLP).
An ultrashort pulsed laser ablation of solids and the accompanying ultrashort pulsed
laser-driven shock wave have an important role on the peening effects. Improvement
of mechanical properties of base material and laser welded 2024 aluminum alloy
using DryLP are described in this chapter.
5.1 Introduction
Laser peening, or laser shock peening, is a surface modification method using a
laser-driven shock wave to improve mechanical properties such as hardness, residual
stress, fatigue properties, and corrosion resistance [1–25]. A nanosecond pulsed laser
is conventionally used as a laser peening tool in aerospace, automotive, medical,
and nuclear industries. The solid which is irradiated by the nanosecond laser pulse
transits into a gas or a plasma via a liquid, accompanied by a volume expansion.
A shock wave is driven as a recoil force during the expansion on the surface and
propagates into the material [2, 4]. The plastic deformation of the material via the
shock wave contributes to the peening effect [1]. In the case using a laser pulse
with a near infrared wavelength (~1.05 μm), the material’s surface needs to be
covered with a protective coating or a sacrificial layer such as a black paint or an
aluminum tape to prevent the surface from melting or sustaining damage from the
Portions of the following text and figures have been reproduced under a Creative Commons
Attribution (CC BY) license of references [1] and [2]
T. Sano (B)
Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka
University, 2-1 Yamada-oka, Suita 565-0871, Osaka, Japan
e-mail: sano@mapse.eng.osaka-u.ac.jp
© Springer Nature Switzerland AG 2020
A. Hu (ed.), Laser Micro-Nano-Manufacturing and 3D Microprinting, Springer Series
in Materials Science 309, https://doi.org/10.1007/978-3-030-59313-1_5
163
Dry Laser Peening: Ultrashort Pulsed
Laser Peening Without Sacrificial
Overlay Under Atmospheric Conditions
Tomokazu Sano
Abstract Laser peening, or laser shock peening, is a surface modification technique
using a laser-driven shock wave to improve mechanical properties of solids such as
hardness, residual stress, fatigue properties, and corrosion resistance. An ultrashort
pulsed laser-driven shock compression of solids enables peening without sacrificial
overlay under atmospheric conditions, which is called Dry Laser Peening (DryLP).
An ultrashort pulsed laser ablation of solids and the accompanying ultrashort pulsed
laser-driven shock wave have an important role on the peening effects. Improvement
of mechanical properties of base material and laser welded 2024 aluminum alloy
using DryLP are described in this chapter.
5.1 Introduction
Laser peening, or laser shock peening, is a surface modification method using a
laser-driven shock wave to improve mechanical properties such as hardness, residual
stress, fatigue properties, and corrosion resistance [1–25]. A nanosecond pulsed laser
is conventionally used as a laser peening tool in aerospace, automotive, medical,
and nuclear industries. The solid which is irradiated by the nanosecond laser pulse
transits into a gas or a plasma via a liquid, accompanied by a volume expansion.
A shock wave is driven as a recoil force during the expansion on the surface and
propagates into the material [2, 4]. The plastic deformation of the material via the
shock wave contributes to the peening effect [1]. In the case using a laser pulse
with a near infrared wavelength (~1.05 μm), the material’s surface needs to be
covered with a protective coating or a sacrificial layer such as a black paint or an
aluminum tape to prevent the surface from melting or sustaining damage from the
Portions of the following text and figures have been reproduced under a Creative Commons
Attribution (CC BY) license of references [1] and [2]
T. Sano (B)
Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka
University, 2-1 Yamada-oka, Suita 565-0871, Osaka, Japan
e-mail: sano@mapse.eng.osaka-u.ac.jp
© Springer Nature Switzerland AG 2020
A. Hu (ed.), Laser Micro-Nano-Manufacturing and 3D Microprinting, Springer Series
in Materials Science 309, https://doi.org/10.1007/978-3-030-59313-1_5
163