Abstract

The mechanisms of nickel thin films irradiated by femtosecond laser pulse trains are studied by a model using molecular dynamics simulations and two-temperature model. It is found that the pulse train technology can change energy transport and corresponding phase change processes. Compared with single pulse ablation at the same total fluence, the pulse trains lead to (1) lower ablation rate with more and smaller uniform nanoparticles, (2) higher film surface temperatures and longer thermalization time, (3) much lower electron thermal conductivity that can further control heat-affected zone, (4) significantly smaller film compressive stresses and tensile stresses which reduce microcracks, and (5) a transition from phase explosion to the critical point phase separation which favors small uniform nanoparticle generation.

Department(s)

Mechanical and Aerospace Engineering

Sponsor(s)

Ministry of Science and Technology of the People's Republic of China. 111 Project
Ministry of Science and Technology of the People's Republic of China. 863 Program
China Postdoctoral Science Foundation
National Natural Science Foundation (China)

Keywords and Phrases

Compressive Strength; High-Speed Optical Techniques; Metallic Thin Films; Microcracks; Molecular Dynamics Method; Phase Change Materials; Phase Separation; Tensile Strength

Library of Congress Subject Headings

Nanoparticles
Nickel
Thermal conductivity

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2009 American Institute of Physics (AIP), All rights reserved.

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