Comparison study of corrosion behavior between electron beam melting formed and forged Ti6Al4V alloys

Abstract:

In this work, the electrochemical dissolution behavior of electron beam melting (EBM)-formed TC4 samples and conventionally forged TC4 in 3.5 wt% NaCl solution was investigated using an electrochemical workstation. The results show that the non-equilibrium microstructure of the EBM formed TC4 samples makes them exhibit different corrosion resistance compared to the conventionally forged TC4. the corrosion resistance of the EBM formed TC4 samples differs in different planes compared to the forged TC4, with the EBM horizontal plane being larger than the forged one, but the EBM vertical plane being smaller than the forged one. the anisotropy of the corrosion properties appearing in the vertical plane of the EBM formed TC4 samples is mainly caused by the β-columnar grain. In the process of corrosion, pitting preferentially occurs at α grain boundaries because of the higher grain boundary energy and the formation of porous passivation layers. This work is helpful to enrich the study of corrosion energy of TC4 alloy prepared by additive manufacturing in the field of aerospace titanium alloys.