Effect of Build Orientation and Heat Treatment on Shear Strength of Additively Manufactured Ti6Al4V Alloy

Abstract

This study investigates the effects of build orientation and heat treatment on the transverse shear properties of additively manufactured Ti6Al4V alloy produced by laser powder bed fusion (LPBF). Specimens were fabricated in three different build orientations (0°, 45°, and 90°) and subjected to heat treatment at 900 °C under argon gas atmosphere. Transverse shear strength was evaluated using the short beam shear test method. The results revealed that build orientation significantly affects both shear strength and ductility of materials. Compared to the 0° reference, the 45° and 90° samples showed an approximately 43% increase in shear strength, along with 56% and 103% increases in displacement, respectively. Heat treatment further enhanced the ductility, especially for the 45° oriented specimen, which exhibited the highest displacement and a 26% increase in shear strength compared with reference 0° sample. However, heat treatment slightly reduced the strength of the 45° and 90° specimens relative to their untreated counterparts. Fractographic analysis confirmed quasi-brittle failure with the presence of dimples, indicating enhanced ductility post-heat treatment. These findings provide novel insight into optimizing process parameters and post-processing strategies to improve the shear performance of LPBF Ti6Al4V components for critical structural applications.