Effects of Laser Peening with a Pulse Energy of 1.7 mJ on the Residual Stress and Fatigue Properties of A7075 Aluminum Alloy

Metals

Kiyotaka Masaki¹  Yoshio Mizuta²  Tomonao Hosokai²  Takunori Taira³  Yuji Sano³  Satoshi Tamaki⁴ 

[1] Department of Mechanical Systems Engineering, National Institute of Technology, Okinawa College, Nago 905-2192, Japan;Department of Quantum Beam Physics, SANKEN, Osaka University, Osaka 567-0047, Japan;Division of Research Innovation and Collaboration, Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan;LAcubed Co., Yokohama 220-0012, Japan;

关键词: laser shock peening;    LPwC;    microchip laser;    X-ray diffraction;    fatigue;   

DOI  :  10.3390/met11111716

来源: DOAJ

【 摘 要 】

Laser peening without coating (LPwC) using a palmtop-sized microchip laser has improved the residual stresses (RSs) and fatigue properties of A7075 aluminum alloy. Laser pulses with a wavelength of 1.06 μm and duration of 1.3 ns from a Q-switched Nd:YAG microchip laser were focused onto A7075 aluminum alloy samples covered with water. X-ray diffraction revealed compressive RSs on the surface after irradiation using laser pulses with an energy of 1.7 mJ, spot diameter of 0.3 mm, and density of 100–1600 pulse/mm². The effects were evident to depths of a few hundred micrometers and the maximum compressive RS was close to the yield strength. Rotation-bending fatigue experiments revealed that LPwC with a pulse energy of 1.7 mJ significantly prolonged the fatigue life and increased the fatigue strength by about 100 MPa with 10⁷ fatigue cycles. The microchip laser used in this study is small enough to fit in the hand or be mounted on a robot arm. The results may lead to the development of tools that extend the service life of various metal parts and structures, especially outdoors where conventional lasers are difficult to apply.

【 授权许可】

Unknown