Orientation Dependent Strain Hardening Behaviour of Isothermally Forged and Precipitation Hardened Inconel 718 Disc

Abstract

Tensile flow behaviour of as-received isothermally forged compressor disc of Inconel 718 alloy in solution treated and precipitation hardened condition varies in tangential and radial directions due to microstructural inhomogeniety. The tensile true stress - plastic strain curves exhibit two slopes defined by Ludwigson relation in both tangential and radial directions. The low ductility and low work hardening exponent (n1 and n2) of radial oriented sample in web region of disc have been explained based on the dislocation storage capacity and dynamic recovery coefficient using Kock-Mecking-Estrin analysis.