Title: Laser shock deforming and induced microstructure evolution of austenitic stainless steel sheet

Authors: Xinmin Luo, Chunzhi Yuan, Xudong Ren, Yongkang Zhang, Kangmin Chen

Addresses: School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China. ' School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China. ' Jiangsu Provincial Key Laboratory of Laser Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013, China. ' Jiangsu Provincial Key Laboratory of Laser Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013, China. ' School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China; Test and Analysis Center, Jiangsu University, Zhenjiang 212013, China

Abstract: The black paint coated austenitic stainless steel sheet ASTM-204L was laser shock deformed by the Nd:YAG laser with the 1,054 nm output wave length and the 20 ns short pulse, when tap water was used as the confinement regime. The macro-deformation of the sheets was examined and the laser induced microstructures| evolution was observed and analysed with the thermo-field emission scanning electron microscope. The experimental results indicate that the plasma detonation wave acted on the sheets| surface upon laser shocking can produce designed deformation when the laser facular is 7 mm dia., the energy density 2 GW cm⁻². The microscopic morphology observation reveals that condensed plasma becomes a magma-like shell, which effectively guarantees the shocking effects of the laser beam due to the ethyl-silicate black paint coating and the confinement stratum. The macroscopic deformation mechanism belongs to the uniform plastic deformation in the thickness limit of the test material; however, in the microscopic mechanism, the twin deformation, slipping and stacking faults in austenite grains become dominant. The material grain boundaries have a negative effect on the plastic deformation of steel sheets upon laser shock processing.

Keywords: Nd:YAG lasers; laser shock deforming; austenitic stainless steel; plastic deformation; microstructure evolution; laser manufacturing; material grain boundaries.

DOI: 10.1504/IJMSI.2010.032495

International Journal of Materials and Structural Integrity, 2010 Vol.4 No.1, pp.87 - 98

Published online: 04 Apr 2010 *

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