The mechanical properties and microstructural changes in Inconel 718 after annealing and aging

Abstract

A superalloy with exceptional mechanical qualities and resistance to corrosion, Inconel is heat treatable and shows microstructural alterations brought on by different heat treatment techniques. The current study focuses on the mechanical characteristics and microstructural investigation of Inconel 718 alloys that have undergone solution annealing and cooling at various media. Furthermore, the alloy plates were considered for the aging (or precipitation) process. Mechanical tests include tensile, compression, bending, and hardness tests. There were two sets of experiments: (1) taking only solution annealed+cooled samples, and (2) taking solution annealed + cooled+aged samples. To conduct each type of test, one sample was evaluated in the 'as received' condition, allowing for a proper comparison of heat treated sample properties to those of a non-treated sample. This work also includes a comparison of the characteristics of 'aged' and 'non-aged' Inconel samples.

The microstructural observation demonstrated that the reduced amount of needle-shaped δ in 'unaged' samples has dramatically risen with aging. Aging resulted in thickening of the γ grain boundaries. These two microstructural modifications significantly lowered the alloy's strength and hardness. Under post-aging conditions, all heat-treated materials become highly deformable due to their reduced strength.