14th International Conference on Shot Peening

Dry Laser Peening: A New Laser Peening Technique using Femtosecond Laser Pulses

Tomokazu Sano

Osaka University, Japan, sano@mapse.eng.osaka-u.ac.jp

Introduction

Dry laser peening enables improving fatigue performance of metallic materials using femtosecond laser pulses without a sacrificial overlay in air [1-4]. The intensity of a femtosecond laser pulse is extremely high even at a low energy because the pulse width is extremely short. Therefore, direct irradiation of a solid surface with a femtosecond laser pulse drives an intense shock wave that propagates into the solid. Such a shock wave driven by the femtosecond laser pulse irradiated under atmospheric conditions deforms a material plastically. Heat-affected and melted zones formed by a femtosecond laser pulse are much smaller than those produced by a nanosecond laser pulse due to its extremely short pulse width. Therefore, peening without a sacrificial overlay in air is possible using femtosecond laser pulses.

Objectives

The objective of this study is to verify the effectiveness of the dry laser peening for laser-welded 2024 aluminum alloy containing welding defects by investigating the mechanical properties.