Laser welding of copper with stellite 6 powder and investigation using LIBS technique

Abstract

This paper reports a process by which two copper plates are welded together by using a millisecond pulse Nd:YAG laser with the addition of stellite 6 powder which increases the absorption of laser energy. It also reports an interesting application of Laser Induced Breakdown Spectroscopy (LIBS) in order to determine the elemental composition and diffusion of stellite 6 powder into the copper plates. The effects of laser peak power and pulse duration are examined to optimize the welding. The amount of stellite 6 powder is also optimized for a high quality welding. The tensile strength and hardness values are measured for different laser parameters. The EDX and SEM results show that the stellite 6 powder particles penetrate into the copper plates and increase the hardness. The elements in laser weld joints of copper plates were analyzed with LIBS, utilizing a high resolution multi-channel CCD spectrometer and a nanosecond pulse Nd:YAG laser, providing a depth profile of elemental composition of the penetrated region.