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The LASer Shock Adhesion Test (LASAT) is based on coating-substrate spallation induced by a power pulsed YAG laser. While the laser induced shock wave propagates in the target, pull back velocity VISAR signals provide a diagnostic about the coating debonding. However, for targets over the millimeter range, the hydrodynamic decay can reduce the tensile stress created at the interface, down to below the debonding threshold. A numerical study shows that the application of a Low-Impedance Layer (LIL) on the impacted face increases stresses at the coating-substrate interface. It is experimentally evidenced by VISAR signals obtained on a 110 μm electro-deposited chromium on copper. Possibilities of pushing up thickness limits of LASAT tested samples are shown. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The LASer Adherence Test so-called LASAT aims to control the interface adhesion of a coating deposited over a substrate which is irradiated by a high power laser intensity. The shock waves propagation yields traction at the interface, likely to debond the coating. This technique has been applied to a copper plasma sprayed coating on an aluminum substrate. During the test, the coating’s pull back VISAR signals clearly evidence characteristic patterns according to the debonding or the integrity of the system. This shows the possibility to use this non-intrusive diagnostic for assessing the bond quality of the coating. The numerical simulations of the experiments performed provide an estimate of the debonding parameters associated with a cumulative damage criterion for the interface of this system. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We introduce a recent application for the impact of a laser driven mini-flyer on Hugoniot measurement of transparent materials and as a demonstrative work, study of water is presented. In this experimental system, water has been used as both the target sample and the window medium for VISAR diagnosis. By allowing the incident beam of the VISAR transmitting through water, both the impact velocity of a mini-flyer and the particle velocity of water at impact were recorded simultaneously. Measurements have time resolution in nanoseconds and a velocity uncertainty of about 1%. Up to 2 GPa, the Hugoniot data are in good agreement with the literature. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]