Magnesium alloy thin-walled cylindrical components with the advantages of high specific stiffness and strength present broad prospect for the lightweight of aerospace components. However, poor formability resulting from the hexagonal close-packed crystal structure in magnesium alloy puts forwards a great challenge for thin-walled cylindrical components fabrication, especially for extreme structure with the thickness-changing web and the high thin-wall. In this research, an ZK61 magnesium alloy thin-walled cylindrical component was successfully fabricated by two-step forging, i.e., the pre-forging and final-forging is mainly used for wed and thin-wall formation, respectively. Microstructure and mechanical properties at the core, middle and margin of the web and the thin-wall of the pre-forged and final-forged components are studied in detail. Due to the large strain-effectiveness and metal flow along the radial direction (RD), the grains of the web are all elongated along RD for the pre-forged component, where an increasingly elongated trend is found from the core to the margin of the wed. A relatively low recrystallized degree occurs during pre-forging, and the web at different positions are all with prismatic and pyramid textures. During final-forging, the microstructures of the web and the thin-wall are almost equiaxed due to the remarkable occurrence of dynamic recrystallization. Similarity, except for few basal texture of the thin-wall, only prismatic and pyramid textures are found for the final-forged component. Compared with the initial billet, an obviously improved mechanical isotropy is achieved during pre-forging, which is well-maintained during final-forging.

Conical rings with thin sterna and high ribs (CRTSHR) are key bearing-load parts of aerospace equipment, which are required to be manufactured with high performance and efficiency. Traditional ring rolling is the most preferred method for manufacturing high-performance ring parts, but it can hardly achieve the forming of CRTSHR due to the extreme geometry of CRTSHR. To solve this difficulty, an innovative constraining ring rolling process (CRR) is proposed in this paper to manufacture CRTSHR. To evaluate the proposed CRR and reveal its deformation behaviors, a thermomechanical coupled FE model for CRR of CRTSHR is established. Then, the experiment for CRR of CRTSHR is performed on a modified ring rolling machine, which proves that CRR of CRTSHR is feasible and the established FE model is reliable. Based on the reliable FE model, the metal flow mode in deformed CRTSHR is analyzed, and the deformation characteristics such as the stress state, strain distribution and the evolution of power parameters in CRR of CRTSHR are revealed. Finally, the influences of key parameters such as the friction factor between ring and molds, the diameter of idle roll and the feed velocity of idle roll on CRR of CRTSHR are investigated by FE simulation.