Experimental and numerical investigations of dynamic strain ageing behaviour in solid solution treated Inconel 718 superalloy

Abstract

Purpose The purpose of this paper is to systematically investigate the dynamic strain aging (DSA) effect in solid solution treated IN718 at different temperatures through experiments and simulations to gain an understanding of the inelastic deformation mechanisms. Design/methodology/approach In the present work, uniaxial tensile tests have been carried out in conjunction with finite element (FE) simulations to investigate the behaviour of the solid solution treated Inconel 718 superalloy at different temperatures and strain rates. Dynamic strain aging (DSA) effects, which manifested during the tests in the form of a negative strain rate sensitivity and stress serrations, are investigated. The most significant DSA effect occurs at 500°C and at a strain rate of 10–4 s-1. In a newly proposed rate-dependent constitutive formulation, the DSA model, proposed by McCormick, Kubin and Estrin, was introduced into slip-assisted solute hardening, and an activation energy-dependent exponential flow rule was adopted. Findings The observed negative strain rate sensitivity and stress serrations are well predicted by a 3 D FE. The FE results indicate that the equivalent plastic strain rate distribution in the specimen gauge length is as highly inhomogeneous as in the other materials exhibiting DSA effects such as aluminium and titanium alloy. During inelastic deformation, propagating high strain rate bands can be closely correlated to the stress serrations. Originality/value For the DSA effect in solid solution treated IN718, the existing researching mainly focuses on the mechanical properties experiment and microstructure observation. In this study, a constitutive formulation, combined with the DSA model, has been proposed, and the mechanical behaviors, including the DSA effect, have been well predicted by a finite element model.

Experimental and numerical analysis of the Portevin–Le Chatelier effect in a nickel-base superalloy for turbine disks application

“…DSA effects are also mentioned in (v) high-strength Nickel-based superalloys tested at around 500 • C as reported in (Fournier et al, 2001;Dudova et al, 2008;Cai et al, 2017) and more recently in (Song et al, 2021a;Zhang et al, 2021). The PLC phenomenon appears in a wide range of materials.…”

Constitutive modeling and numerical simulations for dynamic strain aging in MMFX steel at elevated temperatures

“…The finite element code for the proposed model was also developed by building a user-defined subroutine and its validity is also tested using theoretical predictions from the proposed model as well as the experimental measurements. Using the validated numerical algorithm, some DSA-related phenomena such as the propagation of Lüders band may be further investigated in the future [26,34,48].…”

Examination of Dynamic Strain Ageing Effects during Rapid Quenching of Inconel 718 Superalloy Disc

“…Uniaxial tensile tests at different temperatures (from 20°C to 790 °C) and strain rates (from 10 -4 /s to 10 -2 /s) are carried out to calibrate the material parameters in the mechanical analysis, which have been given in our previous study (see Ref. [10]).…”

“…Bi et al [9] simulated the residual stress evolution in a forged turbine disc during quenching and ageing processes, and analyzed the distortion caused by the residual stress relaxation during the machining process. However, the high temperature rate dependence of the constitutive response of the IN718 alloy is ignored in these models, though negative strain rate sensitivity (NSRS) has been identified for the solid solution treated IN718 alloy [10]. It has been shown in Refs.…”