Laser generation of high-amplitude stress waves in materials

Abstract

Stress-wave environments generated at a confined surface by a pulsed laser were investigated.Experimental measurements and theoretical calculations demonstrated that confinement of the surface with a transparent overlay provided an effective method of generating high-amplitude laser-induced stress waves in the target material. Peak pressures approaching 10 GPa were possible at laser power densities of several times 10 9 W/cm 2 for laser pulse durations ranging from several nanoseconds to several tens of nanoseconds. These pressures were generated in an air environment at standard conditions, thus enhancing their practical utilization for processing of materials and measurements of material properties. At laser power densities greater than 10 9 W/cm 2 , the laser-induced stress-wave environment was controlled by properties of the ionized plasma created near the metal surface. Some enhancement in the amplitude and duration of laserinduced stress-wave environments was observed at laser power densities less than 10 9 W/cm 2 if low thermal conductivity and low heat of vaporization materials were used. Calculations show that peak pressures greater than 10 GPa were possible by superimposing stress waves either through reflection off a high acoustic impedance barrier or through the interaction of stress waves which were generated at different surfaces of a material.

Induction of Engineered Residual Stresses Fields and Associate Surface Properties Modification by Short Pulse Laser Shock Processing

“…Specially wear resistance, stress corrosión cracking susceptibility and crack propagation rate seem to be material properties specially improved by LSP treatments [1][2][3][4].…”

Effect of Laser Peening on Residual Stress and Micro-Hardness of TC4 Titanium Alloy

“…The very first studies investigating the possibility of high energy laser beams to induce shock waves were done at the Battelle Columbus Laboratory in the 1970s [1][2][3][4][5]. Since then considerable attention has been paid to potential application of laser peening in the aerospace and nuclear industry.…”

Laser Shock Processing: an emerging technique for the enhancement of surface properties and fatigue life of high-strength metal alloys

“…Specially wear resistance, stress corrosion cracking susceptibility and crack propagation rate seem to be material properties specially improved by LSP treatments [1][2][3][4].…”