Morphology investigation on direct current pulsed gas tungsten arc weldedadditive layer manufactured Ti6Al4V alloy

摘要

The effects of pulsed gas tungsten arc weldingparameters on the morphology ofadditive layer manufacturedTi6Al4V has been investigated in this study. Thepeak/base current ratio and pulse frequency are found tohave no significant effect onthe refinement of prior betagrain size. However, it is found that the wire feedratehas a considerable effect on the prior beta grainrefinement at a given heatinput. This is due to the extrawire input being able to supply manyheterogeneousnucleation sites and also results in a negative temperaturegradientin the front of the liquidus which blocks thecolumnar growth and changes thecolumnar growth toequiaixal growth.