Investigating the controlled microstructure features and the corrosion performance of laser beam powder bed fusioned Ti6Al4V alloy

Currently, there is a significant level of interest in the use of additive manufacturing (AM) technology for implant applications. The utilization of titanium alloy implants, particularly those employing Ti6Al4V produced via powder bed fusion using a laser beam (PBF-LB), is expected to optimize osteointegration between the implant and the corresponding bone. The corrosion behavior is crucial for such applications and the process parameters of PBF-LB exhibit noteworthy impacts on both microstructure and corrosion behavior. The impact of PBF-LB process parameters, with a particular focus on laser scan strategy and hatch space, on the microstructure control and corrosion properties of Ti6Al4V remains to be comprehensively studied. Therefore, a comparative analysis was carried out to evaluate the efficacy of two laser scanning strategies, namely X scan and XY scan with two different volumetric energy densities (VED). Results showed that martensitic microstructure formed in both samples due to the fast-cooling speed of the PBF-LB process. Moreover, the EBSD results indicated the remelting effect on grain structure in XY and XZ observation planes. Corrosion investigations revealed that the optimum corrosion behavior of the PBF-LBed specimens was obtained from the XY plane of the XY scan strategy. The findings of this study indicate that a controlled microstructure approach via simultaneous change of laser scanning strategy and hatch space can effectively modify the microstructure and corrosion characteristics of Ti6Al4V alloy.