A novel strategy for electrochemical additive manufacturing: Femtosecond laser-assisted localized electrochemical deposition

Abstract

Localized electrochemical deposition (LECD) exhibits significant advantages in fabricating microscale 3D metallic structures. However, conventional LECD technologies are inherently constrained by diffusion-controlled mechanisms, where pursuit of enhanced deposition efficiency inevitably degrades deposition quality (such as increased surface roughness and internal defects), consequently impairing structural mechanical properties. This study presents a femtosecond laser-assisted localized electrochemical deposition (FsLA-LECD) technology. By precisely coupling femtosecond laser irradiation with the electrodeposition microzone and leveraging laser energy to regulate electrodeposition process, this approach simultaneously achieves efficient fabrication of complex metallic microstructures with enhanced mechanical performance. The regulating effects of laser irradiation on mass transfer, nucleation kinetics, and grain growth evolution are investigated throughout the evolution process of point-surface-structure. Experimental and computational analysis elucidate that the laser-induced Marangoni effect within the reaction microenvironment enhances microzone electrolyte replenishment, consequently elevating deposition current density. This results in a volume deposition rate of 15.47 μm³/s, representing a 3 times enhancement over laser-free conditions. Laser-mediated regulation of deposition rates enabled fabrication of uniform-diameter, bamboo-like, and hourglass-shaped microstructures. Furthermore, pulsed laser energy facilitated stepwise current amplification, thereby inducing nanotwin formation within copper micro-geometrical features. This approach attained a tensile yield strength of 1.08 GPa, significantly surpassing that of traditional electrodeposited counterparts. This work demonstrates the capability of FsLA-LECD to simultaneously enable high-efficiency manufacturing and enhanced mechanical properties, establishing the groundwork for innovative approaches to high-performance micromanufacturing.