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Ablation behavior of SiCp/AA2024 composites irradiated by a single-pulse nanosecond laser
摘要： In this study, homogenous Al alloy and SiC materials and SiCp/AA2024 composites with mean particle diameters of 5 μm and 30 μm were irradiated by a single-pulse nanosecond fiber laser with a 200 ns pulse width and 1064 nm wavelength. Using a laser pulse, regular circular heat-affected zones (HAZ) were formed in the homogenous materials. For the composites, an Al allloy matrix was melted and sputtered, and the SiC particles bulged when irradiated by the laser pulse. According to the measured results, the HAZ increased with the pulse energy density in a logarithmic pattern. Nonlinear fitting results demonstrated that the damage thresholds of the composites and SiC homogenous materials were the lowest and highest, respectively. SiCp/AA2024 composites with different mean particle diameters exhibited similar damage thresholds. The measured etching depths of the SiC particles and Al alloy matrix were smaller than the respective values of the homogenous materials. Thermal simulation results revealed that thermal-mechanical coupling occurred between the SiC particles and Al alloy matrix. The SiC particles in the composite heated more rapidly under a nanosecond laser, and the heat was then transferred to the matrix. Large SiC particles constrained the matrix’s molten pool, which accelerated its gasification but hindered further etching.
关键词： Composites materials,Phase transitions,Ablation mechanism,Nanosecond laser irradiating,Interface effect
更新于2025-09-19 17:13:59
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The Effects of Laser Parameters and the Ablation Mechanism in Laser Ablation of C/SiC Composite
摘要： The e?ects of laser parameters and the ablation mechanism in laser ablation of a carbon ?ber reinforced silicon carbide (C/SiC) composite are investigated in the present study. Six di?erent power densities are provided, as well as six levels of pulse numbers, and then ablation experiments are conducted for the C/SiC composite, induced by a pulsed laser. Based on the experimental results, the characteristics of surface morphology and ablation behavior are discussed. It is revealed that the surface morphology of the C/SiC composite under laser irradiation usually includes three regions: the center region, the transition region, and the border region. With the increase of laser power density, the ablation of the center region becomes severe, surface cracks occur, and more spherical SiC particles are found in the transition region. As for scenarios involving multiple pulses, the damage occurs in the center region at low power density limits, within the ?rst two layers below the surface. However, if the power density is relatively high, an ablation pit occurs in the center region when the pulse number is larger than 50. Meanwhile, the transition region and the border region diminish with increase of the pulse number. It is noted that both the power density and pulse number have noticeable e?ects on surface morphology and ablation behavior during laser ablation, which is helpful for material design and performance evaluation of C/SiC composites.
关键词： Surface morphology,C/SiC composite,Ablation mechanism,Laser ablation,Scanning electron microscopy (SEM)
更新于2025-09-12 10:27:22
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Investigation of dielectric layers laser ablation mechanism on n-PERT silicon solar cells for (Ni) plating process: Laser impact on surface morphology, composition, electrical properties and metallization quality
摘要： Laser contact opening is a critical step for solar cells manufacturing and needs to be optimized to achieve high efficiencies. In this paper, laser contact opening using a picosecond laser (wavelength 355 nm, pulse duration 10 ps) has been carried out on n-PERT precursors composed of a SiOx/SiOxNy stack on the rear polished side and a SiOxNy layer on the front textured side. By varying peak fluence from 0.130 J/cm2 to 2.159 J/cm2 and spot overlapping, ninety parameters combinations have been tested to open these dielectric layers. Surface morphology characterization, before and after laser ablation, has been realized using Confocal Laser Scanning Microscopy and Scanning Electron Microscopy. Bulk and surface compositions have also been investigated by Energy Dispersive Spectroscopy and X-ray Photoelectron Spectroscopy analysis, respectively. Results have shown the existence of four separated laser impacted areas on the polished side and a related ablation mechanism is suggested. Also, electrical characterization using four probe measurements and calibrated lifetime photoluminescence revealed that electrical properties of the silicon underlying increased when post laser annealing was performed associated with no spot overlapping. Then, nickel electroless deposition has been performed and first characterizations indicate adherence issues and inhomogeneous metallization. Characterization of metallized samples revealed that these observations were closely linked to the non-homogenous surface morphology and composition after laser ablation.
关键词： Ni plating,Surface damages,n-PERT cell,Ablation mechanism,UV-Picosecond laser
更新于2025-09-12 10:27:22