Analysis of residual stresses of metallic components made by Electron Beam Melting

Due to an increased understanding of additive manufacturing processes and the availability of new equipment for industrial production, the use of metal powder-based processes for industrial applications is growing. Particularly in the case of some titanium alloys, like titanium aluminide alloys, for which Electron Beam Powder Bed Fusion (EB-PBF) is the only method of production. The deposited layers are driven to rapid thermal cycles during the EB-PBF process. Residual stresses may be created by severe temperature gradients. The effective functioning and structural integrity of manufactured parts can be affected by residual stresses. In this study, the semi-destructive hole-drilling method is utilized to measure and compare the residual stresses on Ti 48-2-2 and Ti 6-2-4-2 parts produced by EB-PBF. The technique employs an empirically determined relationship between the magnitudes and directions of the principal stresses and the strain relaxation around the hole to calculate the magnitude and principal directions of residual stresses at the hole location. The trends of residual stresses are compared for different surfaces of these two materials and on simple and more complex geometries.