Atomistic insights of thermomechanical interfacial stripping—a pathway to low-damage femtosecond laser processing of layered materials

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Huang, Zhidong and Feng, Zeming and Cai, Yukui and Zhang, Teng and Tang, Yunqing and Li, Xing and Liang, Xiaoliang and Luo, Xichun and Liu, Zhanqiang (2025) Atomistic insights of thermomechanical interfacial stripping—a pathway to low-damage femtosecond laser processing of layered materials. Journal of Materials Science and Technology, 266. pp. 92-103. ISSN 1005-0302 (https://doi.org/10.1016/j.jmst.2025.12.035)

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Abstract

The micropatterning of multilayer composites enables advanced performance and tailored electromagnetic functionalities. However, precisely removing surface coatings while minimizing substrate damage remains a critical manufacturing challenge. Although femtosecond (fs) lasers are well-established for high-precision ablation with minimal thermal damage, their interactions with layered material interfaces are still poorly understood. Here, we investigate the mechanisms and process of the fs laser ablation of an aluminum film on a glass-fiber-reinforced polymer substrate. Using an extended two-temperature model-molecular dynamics framework for multilayer materials and in situ high-speed imaging of fs laser processing dynamics, we identify and validate a unique thermomechanical removal mechanism: interfacial stripping. Ultrashort laser pulses induce high compressive stresses that propagate into the material and reflect as tensile waves, exceeding the metal's yield strength and causing spallation. The substrate is compressed near its elastic limit and rebounds, propelling the residual metal layer forward. Interfacial stripping occurs when the translational kinetic energy surpasses the interfacial bonding energy. Atomistic insights reveal that interfacial stripping minimizes the heat-affected zone, enables thickness-adaptive removal, and avoids vaporization, thereby achieving low damage, low energy consumption, and superior quality. Experimentally, we achieve complete metal removal with optimized laser parameters. Multi-method characterizations elucidate the thermochemical damage mechanisms of the epoxy substrate, confirming that damage is confined to the nanoscale. Combining atomic-scale simulation, in situ imaging, and multi-technique ex situ characterization, this work demonstrates the unique advantages of the ultrafast laser processing of layered materials.

ORCID iDs

Huang, Zhidong, Feng, Zeming, Cai, Yukui, Zhang, Teng, Tang, Yunqing, Li, Xing, Liang, Xiaoliang, Luo, Xichun ORCID logoORCID: https://orcid.org/0000-0002-5024-7058 and Liu, Zhanqiang;
CORE (COnnecting REpositories)