Two-dimensional model for material damage due to melting and vaporization during laser irradiation

Kar, Aravinda; Mazumder, J.

doi:10.1063/1.346275

Cited by 85 publications

(30 citation statements)

References 9 publications

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“…Contributions of vapor-induced shear forces and recoil pressure in shaping laser produced cavities in solids were shown to have a negligible impact on the cavity axial depth produced for the relatively slow evaporation conditions used in this study [30]. Finally, none of the surface profiles displayed any roughening within the pit that would normally occur if explosive boiling had taken place, and experimental irradiances were well below the phase explosion threshold (10 11 W/cm 2 ) [28].…”

Section: Estimate Of the Evaporation Rates From Surface Profilementioning

confidence: 90%

Evaporation kinetics of laser heated silica in reactive and inert gases based on near-equilibrium dynamics

Elhadj¹,

Matthews²,

Yang³

et al. 2012

Opt. Express

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The temperature dependent evaporation kinetics of silica was measured up to the boiling point3000 K using a CO 2 laser for heating, while the solid-gas phase evaporation chemistry of silica was assessed by using, hydrogen, air, and pure nitrogen gases that served to represent reducing, oxidizing, and neutral environments, respectively. Air, nitrogen, and hydrogen were increasingly more effective in evaporating silica at a given temperature in that order. Hydrogen gas enhancement was attributed to providing an additional pathway for the formation of the evaporation product SiO, while the oxygen in air pushed the balance of the reaction backwards. The problem of mass transport control was addressed experimentally with a gas-nozzle flow configuration co-aligned with the infrared laser heating that allowed varying the gas species feed and removal rates. The apparent mass transport limitations supported the use of a near-equilibrium analysis for the purposes of interpreting the evaporation kinetic data. In combination with an evaporation reaction schemes provided for each gas, the thermodynamics of the reactions were determined and the effective reaction free energies were derived from 2600 K to 3000 K and compared to reported values. With the corresponding mass transfer coefficient, a semiempirical model of the evaporation kinetics of silica is derived that accounts for the heating, gas chemistry, and transport parameters. The experimental and analytical approach described should have broad application to material evaporation, but also in applications requiring study of thermal decomposition chemistry under extreme temperatures. Research highlights Evaporation rates of laser heated fused silica were measured from 2600-3000 K in the presence of hydrogen, air, and pure nitrogen gases  The solid-gas phase chemistry of the reactions involved with oxidizing, neutral, and reducing gases were determined  The process of silica evaporation was found to be mass transport limited  A near equilibrium model is derived to describe the evaporation of silica based on temperature, gas composition, and gas flow rate

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Section: Estimate Of the Evaporation Rates From Surface Profilementioning

confidence: 90%

Evaporation kinetics of laser heated silica in reactive and inert gases based on near-equilibrium dynamics

Elhadj¹,

Matthews²,

Yang³

et al. 2012

Opt. Express

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“…More detailed discussion can be found in refs. [21][22][23]. According to the process of laser irradiation without any gas jet assistance, the workpiece experiences heating, melting, and vaporization phases from the viewpoint of hear transfer.…”

Section: Machining Mechanisms and Experimental Detailsmentioning

confidence: 99%

“…Their simulations predicted the formation of broad-spectrum surface pressure fluctuations due to both the turbulent nature of the gas jet and the blunt shock oscillation on the surface. On the other hand, in order to understand the thermal phenomena and temperature fields, several models for the laser drilling process have been reported in the literature [21][22][23][24][25][26][27]. For example, Chan and Mazumder [21,22] used multiphase model with the heat equation to analytically analyze the evaporation and melt expulsion and discuss the material removal rates.…”

Section: Introductionmentioning

confidence: 99%

Continuous-wave laser drilling assisted by intermittent gas jets

Hsu

Lin

Chang

et al. 2015

Int J Adv Manuf Technol

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We describe a study of the laser drilling of stainless steel (SUS304) using a fiber laser with a wavelength of 1090 nm, assisted by intermittent gas jets. By comparing with the results obtained with the conventional continuous gas jets used in assisted laser drilling, we demonstrate that the use of the intermittent gas jets can effectively increase the material removal rate and reduce the consumption of assist gas. The intermittent gas jets can be modulated according to the frequency to effectively reduce the overcooling effect of the assist gas. Experimental results show that both the drilling depth and machining quality can be greatly and simultaneously improved. Two types of intermittent gas jets, namely, straight and swirling jets, are considered, and the effects of the intermittent frequencies and gas pressures on the laser drilling are investigated and discussed. We conclude that the intermittent gas jet method greatly reduces heat loss and slag formation around the hole exit in the laser drilling process. Compared with the results obtained when using a continuous straight gas jet, laser drilling with a 20-Hz intermittent straight gas jet reduces the drilled hole entrance diameter and increases the drilled hole depth by a factor of up to 1.7. The intermittent gas jet method can reduce the quantity of assist gas being used, and therefore the cost, especially when expensive gases such as helium and argon are being used.

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“…Fluid Flow and Heat Transfer and liquid expulsion was used by Von Allman [7] to calcuThe field equations are the conservation of mass, the late the velocity and the efficiency of laser drilling as a Navier-Stokes equations (the conservation of linear mofunction of the absorbed intensity. A two-dimensional mentum), and the thermal energy equation in cylindrical model for damage due to melting and vaporization formucoordinates, lated by Kar and Mazumder [8], is based on the energy conservation equation and the effects of various parameters on the depth and the radius of holes drilled are studied the Weber number (the reciprocal of the dimensionless ity, u 0 , are taken as 508 Ȑm which is the diameter of a surface tension coefficient) in the input data. typical laser beam and 10 cm/s, respectively.…”

Section: Introductionmentioning

confidence: 99%