Achieving superior tensile and fatigue properties than conventional wrought state via hybrid additive-forging manufacturing

Additively manufactured materials typically contain undesired defects and microstructures. These defects reduce material performance and limit the adoption of the technique in production environments. In this work, we report a hybrid manufacturing strategy that integrates additive manufacturing with hot forging to achieve exceptional mechanical properties in Ti-6Al-4V. The resulting material exhibits improved tensile and fatigue properties compared to its purely additively manufactured and conventionally wrought counterparts. The control of thermal history and plastic flow is capable of healing defects and tailoring microstructure. A series of combined forging and heat treatment processes were undertaken to reveal correlations between fabrication parameters and the resulting microstructures and mechanical response. The underlying mechanisms of microstructure evolution were investigated through systematic and integrated experimental characterization, finite element modelling and mechanical tests. A generic component, representative of an aero-engine blade, was fabricated using this technology, demonstrating the huge promise of adopting this technique in practical applications.