The influence of build parameters and wire batch on porosity of wire and arc additive manufactured aluminium alloy 2319

Porosity was measured for 21 AA2319 wire and arc additive manufacture (WAAM) panels built using different wire batches, cold metal transfer (CMT) modes, wire feed speed (WFS) and travel speed (TS). Image analysis software was used to measure the porosity across two different planes, totalling an area of 84 mm2 approximately 20 layers in height. Porosity was not strongly dependent on CMT mode, WFS and WFS to TS ratio within the ranges tested but batch-to-batch variability in feedstock wire had a significant influence on area of porosity and size distribution. Wire characterisation showed that porosity did not appear to depend on bulk composition but was influenced by surface finish. Surface finish could affect hydrogen content on the wire surface and arc stability which would affect porosity. Further investigation of the relationships between surface finish and surface hydrogen content, and surface finish and arc stability is required to understand porosity formation in aluminium WAAM components.