The gas tungsten arc (GTA) weld brazing of 10 mm copper thick plates without preheating was investigated. The filler metal of Cu–Ag–P eutectic alloy was used in the experiments. The GTA weld brazing and brazing were compared on the microstructure and mechanical performance of their joints. It can be found that the base metal is largely dissolved by the filler metal in the case of infusion of the copper, and the α-Cu solid solution in the weld metal for weld brazing is larger than that in the weld metal for brazing. The average hardness of the weld metal for weld brazing is 50 HV lower than that for brazing. The impact ductility for weld brazing is almost thrice of that for brazing.
