Keyhole formation and power deposit law in Nd:YAG laser welding

The purpose of this work is to understand keyhole formation observed during pulse Nd:YAG laser welding. We determine the power deposit law during laser pulse. We present a calculation of the energy deposit law by Fresnel reflections. The aim is to calculate the ray trajectory in keyhole to deduce the local absorption. A previous study allows to observe keyhole formation using flash X-ray radiography, and determine evolution of keyhole geometry. These results are compared with a previous experimental determination of the interaction efficiency.