uence of the Delta Phase in the Microstructure of the Inconel 718 subjected to 'Delta-processing' Heat Treatment and Hot Deformed

摘要

Inconel 718 (IN718 ) is a nickel base alloy widely used in the aerospace industry due to its mechanical stability at elevated temperatures. Stable 8 phase with acicular morphology weakens the IN718, however, it has been found that a spherical morphology distributed in the grain boundaries acts as an anchor preventing grain growth during hot deformation. The delta processing (DP718) is a saturation of 5 phase in the alloy by thermal treatment followed by thermomechanical working to control the grain growth and morphology during deformation. Two specimens (A and B) of IN718 alloy were solubilized for lh at 1100°C WQ and aging at 900°C for 24hWQ thermal treatment, following by thermomechanical deformation. Sample A was deformed at 0.001 s-1 and sample Bat 0.01 s-1, both deformations were carried out at 960°C and the final microstructures were characterized by optical microscopy and scanning electron microscopy (SEM) in order to evaluate morphology and grain size distribution.