Precipitation behavior during high-temperature isothermal compressive deformation of Inconel 718 alloy

The precipitation behaviors of γ″ and δ phases during high-temperature isothermal compressive deformation of Inconel 718 alloy are investigated under the strain rate of 2.2·10−4 s−1. It is found that the precipitation behaviors are tailored by deformation temperatures, and lead to the disparately abnormal deformation characteristics. Under the deformation temperature of 800 °C, the microstructure is composed of incoherent needle-shaped γ″ precipitates at grain boundaries and ultrafine spherical γ″ particles within grains, resulting in the exceptional decrease of flow stress with absence of DRX. When deformed at 900 °C, it becomes needle-shaped δ precipitates at grain boundaries and intragranular disc-shaped γ″ precipitates, and the DRX softening degree is lowered consequently.