Laser heating mechanism including evaporation process initiating laser drilling

Laser shock processing is a good candidate for surface industry due to its rapid processing, localized ablation, and precision of operation. In the current study, laser shock processing of steel was considered. The numerical solutions for temperature rise and recoil pressure development across the interface of the ablating front and solid are presented. The propagation of elastic-plastic waves in the solid due to recoil pressure loading at the surface is analyzed and numerical solution for the wave propagation was obtained. An experiment was conducted to ablate the steel surfaces for shock processing. Scanning electron microscopy was carried out to examine the ablated surfaces shock processing while transmission electron microscopy was conducted to obtain dislocation densities after the shock processing. It was found that surface hardness of the workpiece increased in the order of 1.8 times of the base material hardness, and the dislocation was the main source of the shock hardening in the region affected by laser shock processing.

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“…where V is the recession velocity of the surface, which can be determined from the energy balance at the surface, [6] i.e.,…”

Section: T͑xy͒mentioning

confidence: 99%

“…where A is the area of irradiated surface, P r is the recoil pressure, ṁ is the rate of mass flow and V ev is the evaporating front velocity, which can be formulated from the Maxwell's law for the velocity distribution of molecules, [6] i.e.,…”

Section: T͑xy͒mentioning

confidence: 99%

Investigation Into Laser Shock Processing

Yilbaş

Arif

Shuja

et al. 2004

Journal of Materials Engineering and Performance

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“…They formulated the evaporation process analytically by assuming constant recession velocity of the solid surface. Yilbas et al [2] formulated analytically laser machining process and evaporation of the surface. Their results were in agreement with the experimental findings for millisecond laser pulses.…”

Section: Introductionmentioning

confidence: 99%

Laser heating: jet emanating from laser induced cavity

Yilbaş

Mansour

2007

International Journal of Thermal Sciences

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“…They showed that the dual gas jet cutting is very effective for laser cutting of thick samples. Yilbas et al (1995) studied the influence of assisting gas on laser cutting process. They showed that the chemical reaction contribution to energy content in the cutting section was about 60%.…”

Section: Introductionmentioning

confidence: 99%