Laser -Based Joining of Metallic and Non-metallic Materials

Abstract

Laser as a high intensity heat source can be effectively used for joining of materials by fusion welding and brazing in autogenous or in hybrid modes. In autogenous mode, welding is done in conduction, deep penetration, and keyhole mode. However, due to inherently high energy density available from a laser source, autogenous keyhole welding is the most popular laser welding mode. But, it has certain limitations like need for extremely good joint fit-up, formation of very hard welds in steel, keyhole instability, loss of alloying elements, etc. To overcome these limitations, innovative variants such as laser-arc hybrid welding, induction-assisted welding, dual beam welding, etc., have been developed. Using laser heat, brazing can be performed by melting a filler to fill the joints, without melting the base materials. Accomplishing laser-based joining as mentioned above requires appropriate choice of laser source, beam delivery system, processing head with appropriate optics and accessories. Basic principles of various laser-based joining processes, laser system technology, process parameters, metallurgical effects on different base materials, joint performance, and applications are explained in this chapter.