Simulation-based qualification of repair and remanufacturing operations through DED technology of Ti6Al4V parts

Qualification of repair and remanufacturing operations through directed energy deposition (DED) offers a sustainable pathway to restore and even enhance the performance of high-value metallic components. By employing additive manufacturing techniques to deposit material onto damaged parts, this approach minimizes downtime and extends the lifecycle of critical components such as molds, dies and tooling. However, integrating newly deposited material with the original substrate poses challenges related to residual stress formation, distortion, and alterations of the microstructural. In this study, qualification is addressed from two interrelated perspectives: (1) the qualification of the component-ensuring dimensional accuracy, minimal residual stresses and preserved metallurgical integrity; and (2) the qualification of the DED process-focusing on buildability through optimized power supply, scanning speed and dwell times. Because extensive experimental testing on high-value parts is impractical and often destructive, simulation studies are the only viable means to qualify repair operations. A simulation-assisted dynamic power control strategy is developed to maintain consistent melt-pool behavior through feedback-based power modulation. The model is calibrated and validated using finite element simulations and targeted experiments. Results demonstrate that power modulation and inter-layer dwell time effectively stabilize the melt-pool and reduce heat accumulation, improving dimensional accuracy, microstructural uniformity, and hardness distribution. However, these benefits are accompanied by increased inter-layer residual stresses due to enhanced thermal gradients. The study therefore establishes the trade-offs between thermal control, mechanical response, and microstructural control in DED-based remanufacturing, providing practical insight into selecting appropriate process parameters for qualification.