The influence of laser fluences on surface properties, plasma formation, and microhardness of Mg-alloy

Abstract

The impact of variation in laser fluence on the surface modifications and plasma parameters of biocompatible, Magnesium (Mg) alloy has been studied. A 1064 nm Nd: YAG laser with, 10 ns pulse duration and a repetition rate of 1 to 10 Hz has been used for this purpose. Mg-alloy targets were subjected to fluences ranging from 1.3 J·cm−2 to 10.47 J·cm−2 in Argon (Ar) ambient. The surface morphology of irradiated targets was analyzed using a Scanning Electron Microscope (SEM). Formation of ripples, ridges, conical structures, pores, and cavities are observed on the surface of the irradiated Mg targets and are shown in the SEM topographical images. A higher initial fluence causes a rise in the size and density of these structures, which subsequently falls off as the fluence increases more to its highest value. Plasma parameters, such as electron temperature (Te) and number density (ne), are measured using Laser-Induced-Breakdown-Spectroscopy (LIBS). It was also found that both Te and ne increase with increasing fluence. XRD analysis is performed to study properties such as phase purity and structural studies were carried out through X-ray diffraction (XRD) technique, aiding in the investigation of material behavior and guiding the development of new materials with specific properties. Using a Vickers Micro hardness tester, we haveinvestigated the hardness of irradiated Mg targets. From the present investigation it is observed that the hardness value of irradiated targets is higher than the pristine Mg target. It is also found that Te and ne play a significant role for the enhancement of hardness as well as for the growth of surface structures on Mg-alloy.