Enhancing High Cycle Fatigue Perfomance Of Electron Beam Melted Ti6Al4V: A Study On Shot Peening And Hot Isostatic Pressing

The qualification of electron beam powder bed fusion (PBF-EB) for safety-critical applications is hindered by variability in high cycle fatigue performance, largely due to surface roughness and internal defects. While Hot Isostatic Pressing (HIP) effectively reduces internal porosity, it does not address surface-initiated fatigue failures. This study investigated the combined effects of HIP and shot peening on enhancing the fatigue performance of PBF-EB Ti6Al4V. Over 50 specimens, including both vertical and horizontal build orientations, underwent high cycle fatigue testing per ASTM E466. X-Ray computed tomography confirmed decrease in defect distribution following HIP, while shot peening resulted in a more uniform surface. Combined HIP and shot peening led to a 100 MPa increase in fatigue compared to machined samples by introducing compressive residual stresses and delaying crack initiation. This study highlights the necessity of integrating combined post-processing strategies in extending the fatigue life of PBF-EB Ti6Al4V