The Microstructural Study of Nd:YAG Pulsed Laser Beam Weld of Copper Beryllium Alloy

Abstract

In this study, the microstructure of Nd:YAG pulsed laser weld of C17200 copper beryllium alloy is investigated by optical microscopy, scanning electron microscopy and X-ray diffraction. The SEM images reveals three distinct solidified structures due to various thermal gradients occurred in the fusion zone. The XRD patterns show that the preferred solidification directions are the same as those of FCC materials. The effects of pulsed laser parameters on the weld pool dimensions were also studied. According to metallographic results, pulsed energy should be kept as low as possible to obtain the weld pool with the highest values of penetration and the least width. In addition, the laser beam diameter should be kept as low as possible. Moreover, polarization was carried out to investigate the effect of passive layer on the reflectivity of surface by incident laser beam. It was found that weld pool increases when the Fresnel absorption phenomenon activated at high pulsed energy.