▎ 摘　　要

The effects of graphene nanoplates (GNPs) on the microstructures and mechanical properties of nanoparticles strengthening activating tungsten inert gas arc welding (NSA-TIG) welded AZ31 magnesium alloy joints were investigated. It was found that compared with those of activating TIG (A-TIG), and obvious refinement of alpha-M-Mg grains was achieved and the finest alpha-Mg grains of fusion zone of NSA-TIG joints were obtained in the welded joints with TiO2+ GNPs flux coating. In addition, the penetrations of joints coated by TiO2+ GNPs flux were similar to those coated by the TiO2+ SiCp flux. However, the welded joints with TiO2+ GNPs flux coating showed better mechanical properties (i.e., ultimate tensile strength and microhardness) than those with TiO2+ SiCp flux coating. Moreover, the generation of necking only occurred in the welded joints with TiO2+ GNPs flux.