Ultrafast Laser Fabrication of Microchannels on Aluminium Alloy Substrate

Abstract

Aluminium alloy 6061 has a versatile application within industrial heat exchangers, heat sinks, chemical equipment, and frames of aircraft and ships. Its physical and mechanical properties such as lightweight, high strength, corrosion resistance, and thermal and electrical conductivity make it a suitable material choice for these applications. Within thermal and micro-electromechanical applications, such as heat exchanges, radiators, and heat sinks used in microelectronics, the dissipation of heat plays an important role. For optimum heat dissipation, a higher surface area is required. This can be achieved by modifying the surface by fabricating microchannels. A number of processing techniques are used for fabricating microchannels on different materials. A laser is a flexible non-contact machining tool that may be used to create any profile or contour on practically any material. In recent times due to the advancement in laser technology, the use of ultrafast laser material processing is one potential route toward further extending the fabrication of high-quality microchannels without defects caused due to heat-affected zones and in a sustainable manner. In this paper, we present an experimental work of fabrication of microchannels on an aluminium alloy 6061 surfaces by using a low power (<4 W) 400 fs laser system. The dimensional accuracy of the fabricated microchannels is assessed using scanning electron microscopy and 3D profilometry. Furthermore, as processing speed and scale is of importance in industrial laser processes, the use of scanning optics is examined as a means of developing a rapid and scalable ultrafast laser process.