The high temperature flow behavior of additively manufactured Inconel 625 superalloy

The combination of Inconel material properties and the geometric freedom of additive manufacturing provides special opportunity for the production of engineered structures with exceptional strength and stability at elevated temperatures. The present work deals with the high temperature flow behavior of an additively manufactured Inconel 625 superalloy in a wide temperature range of 800 °C–1100 °C under the various strain rates of 0.001, 0.01, and 0.1 s −1 . The strain hardening rate analysis was utilized to reveal the critical condition for the occurrence of the restoration processes. The additively manufactured material was capable to be dynamically recrystallized at various thermomechanical conditions. In this regard, the effect of the Zener–Hollomon parameter (Z) on the characteristic points of the flow curves (critical, peak and steady state stresses and strains) was studied using the power law relations. A phenomenological hyperbolic sine constitutive model was proposed to predict the high temperature flow behavior of the manufactured material; and the model was modified considering the effect of imposed strain. Interestingly, the flow stress levels and the average hot deformation activation energy for the additively manufactured Inconel 625 alloy were found to be lower than that for the same alloy which have been fabricated through hot forging. This was attributed to the complex alloy composition and the specified solidified microstructure of the additively manufactured materials.