Numerical Simulation and Experiment Micro-dimple Array on E690 High-strength Steel Surface Induced by Laser Shock Processing

Cao, YP; Jiang, SZ; Shi, WD; Hua, GR; Feng, AX; Wang, ZG

Shi, WD (reprint author), Nantong Univ, Sch Mech Engn, Nantong 226019, Peoples R China.

CHINA SURFACE ENGINEERING, 2019; 32 (5): 69

Abstract

To study how different times of laser shocks affect the micro-dimple, surface residual stress and microstructure of E690 high-strength steel, the finite element software ABAQUS was used to simulate the surface evolution process of the sample. E690 high-strength steel specimens were impacted by pulsed laser with a power density of 7.96 GW/cm(2). Three-dimensional surface morphology was measured by an optical profiler. The surface residual stress and FWHM values of laser-shocked zone were measured by an X-ray diffraction residual stress tester, and the microstructure and morphology of the impacted area were characterzal by using TEM. Results show that when pulse laser with a power density of 7.96 GW/cm(2) impacts 1-4 times, the resultant depths present an increasing trend between 10 and 40 am. A comparison of the simulated and measured results of three-dimensional surface topography in depth-wise direction suggests that the error rate falls within a reasonable range. When pulse laser impacts 2 times and more, test values of residual compressive stress of the specimens tend to be consistent in all directions. FWHM values gradually increase and tended to be equal with the impact being performed 4 and 3 times. TEM images and electron diffraction patterns of specimens that has been impacted by pulse laser for 2 times show nanocrystals forming on the surface of the micro-dimple.

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