Effect of Pulse Cycle on Microstructure and Tensile Properties of AZ80 Magnesium Alloy Fabricated by CMT+P Arc Additive Manufacturing

To address the current issues of coarse microstructure, severe elemental segregation, and insufficient mechanical properties in traditional cast magnesium alloys, in this study, by adjusting pulse cycles (0P, 2P, 5P, and 10P), the wire arc additive manufacturing of single-pass multi-layer AZ80 magnesium alloy walls is realized, and the effects of pulse cycles on the microstructures and mechanical properties of AZ80 magnesium alloys are investigated. The results reveal that the AZ80 alloy walls fabricated under different pulse cycles predominantly exhibit equiaxed grains with uniform size distribution. As the pulse cycle number increases, the Al element distribution becomes more homogeneous, and the content of secondary phases gradually decreases, with the secondary phase volume fraction (3.6%) by CMT+10P process the lowest. The overall mechanical properties in vertical and horizontal directions of the as-deposited AZ80 alloy walls prepared via CMT+10P are the optimal and with no obvious anisotropy. All the four as-deposited AZ80 alloy walls present typical ductile fracture characteristics. The dimples in the facture surface of the as-deposited AZ80 alloy wall prepared via CMT+10P are numerous and densely distributed, making its tensile deformation uniform.