Affiliation:
1. Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
2. Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314019, People's Republic of China
Abstract
The femtosecond laser ablation of metals is a complex and violent nonequilibrium process, and numerous studies have sought to reveal the evolution of a single physical phenomenon, such as laser-induced periodic surface micro-nanostructures or plasma eruptions. By considering the multiphysics scenarios of energy and heat transfer, structural mechanics, hydrodynamics, and nucleation dynamics, a femto-nanosecond and nano-micrometer multiscale framework combining electron–phonon-coupled heat transfer, lattice deformation, phase transition, and plasma eruption was constructed to describe the heat and mass transfer mechanism of femtosecond laser–copper interaction. A multiphysics model was proposed in this study to simulate the ablation process with different laser fluences. Ablation occurs at low near-threshold fluences primarily via a combination of the thermal phase transition process of melting and thermoplastic deformation coupled with the nonthermal phase transition process of hot electron explosion. Marangoni convection and non-uniform nucleation at the solid–liquid interface create micro-nano structures on the surface of the ablation crater. At a high laser fluence, plasma plumes are emitted via gasification and eruption, and as the material is heated to decrease its density, the surface is broken into a micro-column structure, and then the micro-columns fracture and erupt to form micro-nano structures and plasma plumes. Numerical results offer a better understanding of surface topography modifications and plasma plume evolution and promote the application of femtosecond laser precision fabrication in the fields of aviation, mechanics, electronics, and materials engineering.
Funder
National Natural Science Foundation of China
Beijing Institute of Technology Research Fund Program for Young Scholars
Joint Funds of the National Natural Science Foundation of China
National Science and Technology Major Project
Subject
Condensed Matter Physics,Fluid Flow and Transfer Processes,Mechanics of Materials,Computational Mechanics,Mechanical Engineering
Cited by
11 articles.
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