Effects of welding current on macromorphologies, microstructures and mechanical properties of nano-SiC particles strengthening activating flux tungsten inert gas welded AZ31 magnesium alloy joints were investigated by scanning electron microscope and energy dispersive X-ray spectrometer observations and microhardness and tensile tests. The results showed that SiC particles mainly dwelled in the centre and bottom zone of welding pool. Moreover, with the welding current increasing, the mechanical properties of the welding joints were improved by the increased SiC particles in welding pool, the depth/width ratios of weld pool and the refined α-Mg grain size. However, the α-Mg grains coarsened and the mechanical properties of joints decreased due to excessive heat input in welding process when welding current over 115 A.
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