Experimental and numerical investigations of dynamic strain ageing behaviour in solid solution treated Inconel 718 superalloy
ISSN: 0264-4401
Article publication date: 24 July 2020
Issue publication date: 27 January 2021
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.
Keywords
Acknowledgements
This publication has emanated from research conducted with the financial support of the Shenzhen Municipal Science and Technology Innovation Council under Grant Number JCY20160608161000821. Financial support of the National Science Foundation Council under grant number 11872161 is also acknowledged. Yinghao Zhou from Southern University of Science and Technology is gratefully acknowledged for the TEM characterisation.
Citation
Song, R.-H., Qin, H.-L., Bi, Z.-N., Zhang, J., Chi, H., Busso, E.P. and Li, D.-F. (2021), "Experimental and numerical investigations of dynamic strain ageing behaviour in solid solution treated Inconel 718 superalloy", Engineering Computations, Vol. 38 No. 1, pp. 19-35. https://doi.org/10.1108/EC-01-2020-0006
Publisher
:Emerald Publishing Limited
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