Effect of Alternating Parameters on Prior β Grain Evolution and Properties of Ti–6Al–4V Fabricated by Cold Metal Transfer Additive Manufacturing

This study fabricated five straight walls of Ti–6Al–4V alloy using the cold metal transfer additive manufacturing technique. The impact of alternating parameters on the alloy's microstructure, mechanical properties, and corrosion resistance was explored. The findings indicate that the average grain widths of the sample fabricated by alternating the arc mode and travel speed (TS) are 0.735 and 0.760 mm, respectively. Their average lengths are 1.322 and 1.794 mm, respectively. By alternating the parameters, the prior β grain size is significantly reduced. The epitaxial growth behavior of prior β grains in the titanium alloy is disrupted, and the sample's anisotropy is efficiently lessened. Compared with constant parameters samples, the elongation IPA of alternating arc mode sample decreases by up to 81.8%. For alternating TS sample, the standard deviation of the hardness distribution is reduced to 11.97. Alternating TS enhanced the sample's corrosion resistance, with a reduction in surface corrosion pits and a corrosion current density decreased to 3.01 × 10 ⁻⁵  A/cm ² .