Interval Island Laser-Scanning Strategy of Ti–6Al–4V Part Additively Manufactured for Anisotropic Stress Reduction

The powder bed fusion (PBF) process using Ti–6Al–4V powder has the specific application in additive manufacturing of a high-performance structural parts in the aerospace and medical industries. The PBF involves the repeated accumulation of laser melted layers. Consequently, high anisotropic residual stresses and local temperature accumulation occur during the rapid melting and cooling in the process. These factors affect the mechanical properties of the as-built structure. In particular, we revealed the effective interval island laser-scanning strategy with less grain size, thermal effect and anisotropic residual stresses of the additively manufactured structure, compared to those of the strip and continuous laser-scanning strategies. Through the cantilever experiment, it was confirmed that the interval island laser-scanning strategy reduced deformation by up to 7.7% compared to that of the conventional strip laser-scanning strategy due to the reduction of anisotropic residual stresses.