A Material Surface Modification Method of Thermodynamic Composite Underwater Laser Shock

Abstract

The invention provides a material surface modification method for thermal composite underwater laser shock, comprising the steps of: building a processing platform for the underwater environment, adjusting the pulse laser to a circular pulse laser beam and flat-top energy distribution; adjusting the focus of the pulse laser beam and The surface of the material to be processed has a positive defocus, and the energy density of the pulsed laser beam receiving radiation on the surface of the material to be processed is guaranteed to be 1-5GW / cm 2 , The thickness of the surface ablation layer is less than 200μm; use the above-mentioned determined pulse laser conditions to perform laser shock treatment with a single laser beam on the surface of the material to be processed, and determine the multi-point area according to the microscopic mechanical properties in the single laser beam irradiation area on the surface of the material to be processed Lap rate during laser shock treatment; actual material surface modification using established laser beam shock conditions. The method of the invention makes the surface of the finally obtained material smooth, and the residual stress is uniformly distributed, and the obtained material presents a distribution state of mechanical properties of external hardness and internal toughness.

Description

technical field [0001] The invention relates to a material surface modification method for thermodynamic composite underwater laser shock, belonging to the technical field of material surface strengthening and modification. Background technique [0002] Laser shock material surface processing is a method based on the force effect of pulsed laser to achieve the purpose of material surface modification. In the conventional laser shock processing technology, the laser beam with ns level and faster pulse time induces high temperature and high pressure plasma to form a GPa level shock wave acting on the surface of the material, which is considered to be the material surface processing principle of the laser shock method. With the development of high-speed photography and other technologies, technicians proposed a new surface modification technology based on the combined use of plasma shock and cavitation effect based on the occurrence conditions of laser-induced underwater cavita...

AI Technical Summary

Problems solved by technology

[0003] In a liquid environment such as underwater, it is difficult to apply absorbing layer materials such as black tape; however, coating without an absorbing layer will cause severe ablation on the surface of the material, resulting in increased surface roughness and weakened tissue properties.

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