A study of the breakdown mechanism of AISI 304 stainless steel, type 2024 aluminum and various titanium coatings
Beelby, Michael Howard
Ulrich, Henry George, III
Challenger, Kenneth D.
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An investigation, experimental and theoretical, into the breakdown mechanisms and associated minimum power levels required for the breakdown and unipolar arcing was conducted for AISI 304 stainless steel and Type 2024 aluminum. The experiment was conducted using a neodymium-glass Q-switched laser. A system of filters was used to attenuate the irradiance on target to the point at which no damage was discernible following laser-target interaction. Experimental results show that above a certain critical power density, surface breakdown occurs. The primary mechanism of surface damage at the power density threshold is by unipolar arcing. Titanium coasted stainless steels were exposed to energy density levels on the order of 5 GW/CM(2). The titanium coating significantly reduced or eliminated the number of unipolar arcs observed. A model is proposed for the physical processes involved in the first few nanoseconds before breakdown.
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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