Laser additive manufactured Ti–6Al–4V alloy: tribology and corrosion studies

The effect of heat treatments (HT) on wear and corrosion of direct metal laser-sintered Ti–6Al–4V specimens have been studied. Rectangular parts were built in vertical (VB) and horizontal (HB) directions and heat treated above β transus and below β transus with different cooling rate. Rotary wear tests have been carried out under varying loads of 5 N, 15 N and 25 N at 25 m/s. Corrosion behaviour were analysed in 1 M H₂SO_4,1 M HCl and 3.5% NaCl solutions. Wear volume loss of both HB and VB are less in specimens subjected to HT 2 than in HT1 which is attributed to more grain refinement. Presence of compact oxide debris on the surface of HT 2-VB specimen could have contributed to the low wear volume. A sharp positive difference could be observed in OCP immersed in 1 M H₂SO₄solution from −0.6 V (as-sintered) to 0.069 V (HT 1-HB) and 0.089 V (HT 2-HB). Icorr value in 1 M H₂SO₄ improved after both the heat treatments from 17.450 μA/cm² to 1.470 and 0.152 11 μA/cm², respectively. Generally, heat-treated specimens (both horizontal and vertical) show better corrosion resistance than the as-sintered specimens in all the three media.