Cavitation erosion is an especially destructive and complex phenomenon. In order to understand its basic mechanism, the dynamics of laser-induced vapor bubbles have been investigated. Special experimental devices have been used to record ultrafast visualizations and pressure measurements. From these measurements, the different sources of stresses, induced on the solid wall by the presence of the bubble (shock wave, microjet), have been characterized. The “water hammer” pressure associated with the microjet velocity varies up to 210 MPa. When the bubble collapses near a solid wall, the pressure emitted is less than in an infinite medium. Pressure values up to 2.5 MPa have been found. These values have been associated with the duration of the pressure applied to the solid wall, which is about 30 ns for the microjet and more than 300 ns for the shock wave. These results have been correlated with the analysis of damage created on the surface sample.

This paper deals with an experimental study on the mechanisms of laser surface cleaning process in a liquid medium.Experiments have been performed with oxides of different compositions irradiated with two different wavelengths: 1064nm, 532nm . Interpretations have been inferred from high speed visualizations, pressure recordings and surface samples analysis. Interesting results on the dynamics of the cavity resulting from ablation and its potential contribution to the cleaning effects have been carried out.

Comportement d'une bulle de cavitation à proximité d'une paroi solide Contribution à l'étude du mécanisme d'érosion par J.-c. Isselin, A.

The surface cleaning effect is investigated here using Nd YAG and Excimer User irradiation The different kind of mechanisms encountered are studied as function of laser interaction parameters: energy density: 0.1J/cm2 - 10J/cm2, pulse duration : 10ns - 20ns, wave length radiation: 248nm - 532nm - 1064nm, laser repetition rate: 1Hz - 200Hz.

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