Influence of Aging Treatment on Microstructural Evolution and Mechanical Properties of FGH2907

Near-net-shape forming of alloy rings is regarded as a promising approach for manufacturing critical components in aero-engines. In this work, FGH2907 is aged at 785 °C for different durations to investigate the evolution of its microstructure and mechanical properties. The results indicate that the tensile strength initially increases and then decreases with increasing aging time, whereas the ductility continuously decreases and reaches a minimum at 2 h. After aging for 1 h, the γ′ phase is finely and uniformly distributed in the matrix, while only a small amount of ε phase is present, leading to an optimal balance between strength and ductility. When the aging time increases to 2 h, both the acicular ε phase and the spherical γ′ phase undergo noticeable coarsening, which significantly enhances the strength but results in a marked reduction in ductility. With further aging to 4 h, secondary nucleation of the ε phase and γ′ phase occurs, this weakens the precipitation-strengthening effect, causing a reduction in strength while the ductility shows a slight recovery. These findings provide experimental evidence and theoretical support for optimizing the heat-treatment process of powder-metallurgy FGH2907 alloy rings.