Effect of pulse frequency on the morphology, microstructure and properties of deposited layer in arc additive manufacturing of 6061 aluminum alloy

Objective The aim is to provide a reference for the selection of process parameters of 6061 aluminum alloy arc additive manufacturing. Methods A tungsten inert gas (TIG) arc additive manufacturing platform is constructed. The research focuses on the impact of different pulse frequencies mode on morphology, microstructure and mechanical properties of 6061 aluminum alloy deposited layers. Results The result of research shows that with the increase of pulse frequency, the fish-scale pattern of the single-layer weld gradually becomes denser, the fusion width of the single-layer weld shows a change rule of decreasing first and then increasing, the fusion height shows a change rule of increasing first and then decreasing. The average grain size of the single-layer multi-track deposition sample decreases and then increases within a certain range, its elongation after fracture continues to increase, the tensile strength and yield strength show a trend of increasing first and then decreasing. Conclusion When the peak current is 170 A and the pulse frequency is 2.5 Hz, the mechanical properties of the samples reach their optimal levels. The tensile strength reaches 166.6 MPa, the yield strength is 129.2 MPa and the average hardness is 61.3 HV.