Study of Tensile Strength of Aluminum Alloy Caused by Pulsed Laser Drilling

Abstract

In the process of pulsed laser drilling, the material properties in the heat-affected zone will change due to the thermal effect of the laser. To study the effect of this change on the material tensile strength, two lasers were used to punch the standard 6061 aluminum alloy specimens with millisecond and nanosecond pulse widths, and then the tensile test was carried out on the standard specimens with a tensile tester to measure the ultimate tensile strength of the aluminum alloy. Finally, the micro-morphology of the fracture was photographed by scanning electron microscopy (SEM), and the fracture mechanism of the aluminum alloy was analyzed. The experimental results show that the relationship between the rate of intensity change induced by the millisecond laser and the ablation area ratio is more linear than that of the nanosecond laser; with the increase of ablation area ratio, the rate of intensity changes induced by the nanosecond and millisecond lasers becomes increasingly closer; three types of fractures are produced with two types of laser ablation; the plasticity of the material rapidly decreases with laser drilling, and the main reason for decrease in plasticity was stress concentration. This study provides an important point of reference for how to ensure the strength and plasticity of the components after laser drilling.

Picosecond laser drilling grids in aluminium foil at 532 and 355 nm wavelengths

“…Any substance under such laser irradiation experiences phase transitions into all states, including plasma which in turn may change chemical composition due to nuclear reaction [3,4]. High-energy laser beams, along with the ability to focus them into a small spot diameter, are utilized in technological processes such as laser cutting, welding, drilling, and surface hardening [5][6][7]. The new generation of solid-state lasers with pulse energy up to 10 mJ and a duration of 10 ns, has already become a versatile tool for microdrilling and micro-cutting of various materials [8][9][10].…”