A Review on Ultrafast Laser Microwelding of Transparent Materials and Transparent Material–Metals

Abstract

Transparent hard and brittle (THB) materials have generated significant interest due to their excellent properties, such as wide spectral transmittance, heat resistance, chemical inactivity and high mechanical strength. To further explore the application of THB materials, it is inevitable to be confronted with a range of joining THB materials and THB material–metals. Ultrafast (UF) laser microwelding enables a new means of joining THB materials and THB material–metals, due to a localized energy deposition method, which is dominated by nonlinear absorption. This process can realize high-quality micro-zone direct joining of THB materials or THB material–metals without the assistance of a light-absorbing intermediate layer. In this paper, we review the advances in UF laser microwelding of THB materials and THB material–metals considering the last two decades, from the analysis of the interaction mechanism between UF laser and matter to the key influencing factors and practical applications of this technology. Finally, the existing problems and the future research focus of UF laser microwelding technology of THB materials and THB material–metals are discussed.

Optical parameters impact on glass-to-metal welding

“…Among the many parameters that govern USP laser pulses and matter interaction, we analysed the influence of the ablation threshold of the selected metals on the final mechanical properties of the weld. As showed in literature [2][10], glass-tometal welding happens through the interconnection of the glass and metal surfaces, creating a bonded union between the two materials, and sharply increasing the contact surface between the two. In order for this to happen in a controlled way, the metal ablation mechanism as well as the glass melding mechanism must be understood thoroughly.…”

“…Among the different material processing based on fs laser, USP laser welding has emerged as a reliable technique, offering exceptional joint strength for hermetic sealings without the need for glue or heat treatment. Glass-to-glass welding is now a well proven technique [2], but the adoption of glass-to-metal welding by the industry is still facing setbacks due to difficulties in achieving high weld strength in real applications. In fact, one crucial aspect to consider when joining such dissimilar materials is the weld's resistance to aging and thermal cycles, which can lead to stress accumulation and ultimately to rupture.…”