Paper Title
Heat Treatment and Cavitation behaviour of the INCONEL 718 in Different

Abstract
The cavitation behaviour and microstructure with phase precipitate behavior and their effects on the room temperature mechanical properties of Inconel 718 aged at 800°C for 5, 10 and 20 hours were investigated by stereomacroscopy, optical microscopy and SEM. The as-received alloy shows a hardness value of 311 HB (35HRC). After an aging treatment at 800°C for 5 h and cooled in air (standard heat-treated condition), fine γ′ phase particles precipitate within the grains, solid solution  precipitation, and small carbide particles are located at the grain boundaries the hardness decreases to 264 HB (28 HRC). A lowest hardness value of 247 HB (respectively 24 HRC) is achieved for the alloy aged at 800 °C for 20 h. With increasing the aging time from 5 to 20 h, an increase of the hardness and toughness is observed along with an enhanced quantity of NbC particles, precipitation od  solid solution and the coarsening of γ′ phase. The cavitation behaviour reveals a very good resistance of the superalloy, no mater the heat treatment state was, with a erosion/cavitation depth around 5µm and an attacked surface aroud 85-90%. Keywords - Cavitation Erosion, Heat Treatment, Superalloy INCONEL 718