Effect of Thermomechanical Working on the Microstructure and Mechanical Properties of Hot Pressed Superalloy Inconel 718

Experimental results on hot deformation and dynamic structural processes of nickel based alloy Inconel 718 are reviewed. The focus is the analysis of dynamic precipitation processes which operate during hot deformation of these materials at elevated temperatures. Hot compression tests were performed on the solution treated precipitation hardenable nickel based superalloy Inconel 718 at 720-1150°C with a constant true strain rates of 10 -4 and 4x10 -4 s -1 . True stress true strain curves and microstructure analysis of the deformed nickel based superalloy is presented. The properties and dynamic behaviour are explained through observation of the microstructure using standard optical, scanning and transmission electron microscopy. Structural observations of solution treated Inconel 718 deformed at high temperatures, reveal non uniform deformation effects. The distribution of niobium-rich carbides were affected by localized flow within the strain range investigated at relatively low deformation temperatures 720 850°C.