Influence of raster orientation on fracture behavior of Ti6Al4V alloy manufactured by Laser powder bed fusion

This study analyzes the fracture characteristics of Ti6Al4V alloy manufactured by the Laser Powder Bed Fusion (LPBF) technique, specifically investigating the effect of raster orientation. A modified yield function is presented to determine the decrease in load-carrying ability attributed to shear effects. The damage variable includes both the void volume fraction and shear damage variables, taking into consideration the consequences of void interaction. The research utilizes Finite Element Analysis (FEA) together with calibrated modified GTN fracture parameters derived from Hill's 48 parameters to accurately predict material behavior. Uniaxial tension tests are carried out on samples in different raster orientations:0°, 45°, and 90°. The Scanning Electron Microscope (SEM) is used to conduct a more thorough examination of the fracture's characteristics. The specimens with a 90° raster orientation exhibit considerable plastic deformation with deep dimples on the fractured surface, along with irregularly shaped voids. In contrast, the sections with 45° and 0° orientations display smaller dimples and smoother cup and cone features without significant plastic deformation. The results demonstrate that the direction of the raster has a considerable impact on the plastic modulus and fracture properties of the material.