A novel cast & wrought hybrid manufacturing of FGH4096 superalloy: Achieving high performance with reduced production cost

Abstract

Despite their superior high-temperature capabilities, powder metallurgy (PM) superalloys face critical limitations in industrial scalability due to intricate processing routes, prohibitive costs, and inherent susceptibility to contamination by inclusions. To overcome these challenges, this study pioneers a hybrid manufacturing strategy integrating electron beam directional solidification (EBDS) with isothermal forging to fabricate cast-forged FGH4096 superalloy, achieving unprecedented cost-effectiveness, process efficiency, and mechanical performance. The EBDS technique produces ⟨001⟩-textured columnar grains (0.5–1 mm width), while subsequent isothermal forging and heat treatment induce more than 82 % dynamic recrystallization, eliminating casting defects and refining γ′ precipitates to a bimodal distribution (40–65 nm secondary γ′). Compared to conventional PM counterparts, the developed alloy exhibits a 10 % higher yield strength (1038 MPa at 750 °C), attributed to its hierarchical microstructural features, including high-density nanoscale twins (2.2 nm spacing) and stacking fault (SF) networks. These findings provide a better understanding of the complex interactions between γ′ phase, microtwins (MTs), SF and high-temperature properties, offering insights into improving the short-process, low-cost preparation of cast & wrought FGH4096 alloy.