Exploration of pulse timing for multiple laser hits within a combined heat transfer, phase change, and gas dynamics model for laser ablation

Laser annealing of laser additive–manufactured Ni-Ti structures: An experimental–numerical investigation

“…With increase in grain size, the general effect of annealing is clearly visible in Nd:YAG laser annealing than the diode laser annealing. 12 Risk of ablation is high while using infrared laser for annealing, 13,14 whereas in Nd:YAG laser annealing the risk of ablation is under control. The same Nd:YAG laser is not able to produce smoother surface morphology revealed by SEM when annealing was done at the wavelength of 1064 nm.…”

“…12 Also, there are some published literature reporting laser annealing of Ni-Ti structure by repeated scanning of continuous-wave infrared laser systems. 13,14 There are also reports that pulsed Nd:YAG laser is deployed for annealing Ni-Ti thin film with various power spots at a wavelength of 1064 nm developed by sputtering on silicone substrate. 15 During the literature survey, it is found that there are no published reports on usage of Nd:YAG laser at 532 nm wavelength for annealing bulk Ni-Ti structures developed using LAM.…”

Temporal and spatial temperature modelling for understanding pulsed laser induced solution based nanomanufacturing

“…The temperature measurements for solution based pulsed laser processes are subjected to particular materials, specific temperature ranges, time or spatial constraints [12][13][14]. Moreover, the assumption such as the linear relationship between laser power and temperature [15,16] could not provide accurate results with temporal resolution comparing to pulse width or spatial resolution within the laser spot.…”

“…Moreover, the assumption such as the linear relationship between laser power and temperature [15,16] could not provide accurate results with temporal resolution comparing to pulse width or spatial resolution within the laser spot. The heat transfer model is therefore an effective tool for obtaining temperature profiles in laser applications [14,[17][18][19]. For example, in modelling laser chemical vapor deposition (LCVD) [20,21], temperature evolution could be simulated considering the forced convection air flow [22,23] and the effect of natural convection for both stationary and moving laser [24,25].…”

Experiment and simulation on responses of polymer induced by laser irradiation

“…So far, glory fruits have been achieved in experimental and theoretical studies, and massive literatures can be obtained also, such as the theoretical analysis presented by Povarnitsyn et al [1][2] ,which was based on the classical heat transfer theory and studied the ablation model of target materials under a single pulse laser beam; On consideration of the material constitutive effects, Wang et al [3] described the connected effects among micro-damages in the late damage stage by using a stress relaxation function, they also performed the numerical simulations of dynamic mechanical response and spallation failure experiments of aluminum under high laser irradiation. By using the microanalysis on aramid fiber reinforced plastics sample recovered from the ablation experiments in different laser power, Wang et al [4] obtained the thermal damage morphology and damage physic-chemical processes under different laser parameters; with the help of electromagnetic device, Ebihara [5] deposited high quality ZnO nano-structure film by using the separated pulsed laser deposition (SPLD), Cultrera [6] studied the strong emission of particulates towards the incident beam direction in pulsed-laser ablation experiments; in order to predict where, when, and what stresses occur during laser grooving, Xiang et al [7] proposed a three-dimensional elastic stress model and integrated it into ablation solution; with a Gauss function standing for the pulsed laser power density distribution, Zhang et al [8] discussed the effect of the pulsed laser power density distribution function on temperature distribution of the target surface before melting in ablation process; Christensen et al [9] simulated the two-temperature model Au, Ag, Cu and Al and proposed an analytical model for the ablation rates in the high fluency regime; Mullenix and Povitsky [10] developed a laser ablation model and pointed out one can control the total mass ablated and the mass transfer rate by changing this interval. Although the materials response in laser irradiation has been studied intensively, studies on how to reduce internal damages in MEMS laser fabrication can hardly be seen.…”