Laser Ablation of Copper Alloy under Varying Environmental Conditions to Achieve Purpose-Built Surface Structures

Abstract

In the manufacturing industry, surface structures and surface topographies present at functional areas of the mechanical parts play a vital role in various performance characteristics, such as corrosion resistance, weldability, and wear behaviors, etc. Copper–zinc alloys are extensively used in the manufacturing industry. Laser ablation has the potential to create a variety of surface structures on the ablated substrate. The size and geometry of such structures largely depend on the selection of process parameters and the ablation environment. In the present study, a copper–zinc alloy (95% Cu and 5% Zn) has been laser ablated under different gaseous and magnetic environments to realize a variety of micro-structuring at the ablation surfaces. The effect of plasma plume pressure on the geometry of the structures is deeply investigated through optical emission spectroscopy (OES) and scanning electron microscopy (SEM). By analytically evaluating thermal beta (βt), directional beta (βd), and containment radii (Rs) for the plasma of the Cu–Zinc alloy, the validity of magnetic confinement has been proven. In general, five types of microstructures are produced: micro-sized spherical cones, mounted ablated networks, cavities, pores, ridges, and ablation channels with uplifted cones. Moreover, it has been found that, under a magnetic environment, the geometry of the structures is distinct and well-defined compared to those structures achieved when the ablation is carried out without applying a magnetic field.