Laser welding of copper-niobium microcomposite wires for pulsed power applications

摘要

The laser welding of copper-niobium microcomposite wires was investigated. It was determined that the joint structure does not have welding defects, while microscopic examination of the joint cross-section showed that the microstructure of the autogenous weld consists mainly of a copper-based solid solution strengthened by niobium-rich precipitations. The weld obtained with use of filler material consists of two distinct zones, which are formed due to melting of filler wire and microcomposite wire. This structure of the joint provides an insignificant increase in electrical resistance and sufficient ultimate strength and plasticity of the joint. The tensile strength of the sample welded without filler material reaches 335MPa, but such welded joints are very brittle due to very low ductility. However, an autogenous laser welding joint has about 1.6 times better ductility, and the tensile strength of the joint depends on the applied filler material and is equal to the tensile strength of this material.