Laser welding of molybdenum and stainless steel with Cu-Ti filler metal

Brittle Mo-Fe intermetallic compounds (IMCs) are usually fatal for the joining of Mo and steel. In the present work, Ni-free joining of Mo and stainless steel was successfully achieved by laser welding with Cu-Ti filler metal. The entry of Mo element into the weld seam and the formation of Mo-Fe IMCs was significantly suppressed. TiFe, TiFe2, Ti5Cr8Fe16, and Cu -Ti -Fe phases were found inside the weld and near the interface. The IMCs were separated by Cu matrix and no continuous layered IMCs were found. The brittle fracture characteristics of Ti-Fe IMCs and plastic deformation of the Cu matrix was found on the fracture surface in the weld.