Tailoring sapphire–invar welds using burst femtosecond laser

作者：Xuemin Jia, Yuyang Chen, Zhaoxi Yi, Jiawei Lin, Jinlin Luo, Kai Li, Cong Wang, Ji’an Duan, Dmitry Polyakov, Vadim P. Veiko · 发表于：Light Advanced Manufacturing · 年份：2025 · DOI：10.37188/lam.2026.003 · 被引用次数：15 · 研究领域：Laser Material Processing Techniques、Welding Techniques and Residual Stresses、Hydrogen embrittlement and corrosion behaviors in metals

The efficient and robust joining of transparent metal-dissimilar materials remains a significant challenge in high-performance system integration.A primary barrier is the inherently rough surfaces of metals, which hinder reliable bonding with transparent materials, largely due to the limited understanding of the underlying welding mechanisms.In this study, we demonstrate ultrafast laser joining between sapphire and metal substrates with surface roughness (Sa) up to 2 μm, achieving a maximum shear strength of 11.73 MPa.High-speed imaging techniques were employed to conduct the first systematic investigation of coupled absorption dynamics at heterogeneous interfaces.The plasma ejection observed during welding indicated that the molten metal actively confined the interfacial region, transforming the initial free space into a confined space.This transition facilitates the formation of an optical contact condition, significantly improving the joint strength.To further explore the potential of pulse shaping in controlling interfacial behaviour, the effects of temporal shaping (Burst mode) on laser energy deposition, joint strength, and interfacial morphology were examined.Consistent joint quality was achieved across a range of burst parameters, with shear strengths ranging from 9 to 13 MPa.Fractographic analysis indicated that the fracture was predominantly governed by the internal stress within the sapphire, thereby limiting further improvements in joint strength.The revelation of...