This study aimed to examine the corrosion behavior of Inconel 625 in a molten salt system of sodium sulfate and vanadium pentoxide at varying temperatures and durations. The corrosion products, microstructure, and element distribution of hot extruded Inconel in Na₂SO₄ and V₂O₅ molten salt systems were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) analyses. This study demonstrates that corrosion of the alloy increases with time at a constant temperature. During the initial stage of corrosion, the surface of the alloy is primarily composed of a dense oxide layer consisting of Cr₂O₃ and NiO. However, after exposure to the salt bath for 24 h, a chemical reaction occurs between the alloy and vanadium (V), resulting in the formation of CrVO₄ and Ni₃V₂O₈. Furthermore, the intrusion of sulfur (S) element into the matrix leads to the formation of internal sulfides, including Ni-, Cr-, and Mo-based sulfides, which accelerate intergranular and intracrystalline corrosion. As the corrosion temperature rises, the surface microstructure of the corrosion layer transforms from powder to salt particles and then to massive particles. The corrosion products exhibit a clear stratification, while the alloy undergoes simultaneous oxidation and vulcanization processes.

Hot isostatic pressing (HIP) technology is an efficient near-net-shape forming method to prepare complex-shaped structural components. However, for non-axisymmetric components with a complex shape, the powder flow and densification behaviors during HIP are still not clear, leading to a need for lots of experiments to optimize the process parameters. In the current work, a typical aerospace thin-walled tubular component with non-axisymmetric inner ribs was selected as the research object, and its instantaneous powder flow and relative density during the whole HIP process were investigated by a numerical simulation method, focusing on the influence of HIP process conditions on powder densification. The simulation results indicate that the upper end of the Ti6Al4V thin-walled tubular part is preferentially densified, and the lowest densification is observed at the inner rib of the cylinder wall. Moreover, the effect on densification of each HIP condition, including sintering temperature (900–970 °C), pressure (120–180 MPa), and holding time (3–4 h), was evaluated separately. The HIP sintering temperature contributes the most to the improvement of densification, followed by the pressure, while the holding time contributes the least. Investigating HIP densification behavior is beneficial to the structural and process optimization of metal near-net-shape forming applications.