Effect of laser bionic treatment on the microstructure and mechanical properties of TIG welded AZ31B magnesium alloy joints

In order to improve the mechanical properties of TIG welded magnesium alloy joints, the TIG welded AZ31B magnesium alloy joints were processed by laser bionic treatment. For the TIG welded joint, the crystal orien-tations of the heat affected zone (HAZ) were similar to the base metal (BM) with a (0002) basal plane texture, and the grain size in the HAZ was slightly larger than that in the BM; the fusion zone (FZ) was composed of equiaxed grains with the largest grain size and relatively random crystal orientations. After laser bionic treat-ment, due to the rapid heating and cooling of laser processing, the crystal orientations of the laser treated zone (LZ) in TIG welded joint were more random without obvious texture. The grain size in the LZ was obviously refined. The tensile properties of welded joint could be improved effectively by adjusting the laser bionic stripe spacing and distribution angle. The grain refinement in the LZ and the stress transfer between the FZ and LZ in the bionic welded joint sample were contributed to the improved tensile properties.

Automated summary

The study showed that laser bionic treatment can effectively improve the mechanical properties of TIG welded magnesium alloy joints by refining grain size and adjusting crystal orientations.