Representing the superplasticity of Inconel 718

Abstract

Modelling the superplastic process using finite element analysis can enable optimum process parameters to be determined and lead to a better understanding of the process. Constitutive equations, which accurately represent a material's behaviour, are very important in the development of representative process models. The development of a set of constitutive equations for superplastic grade Inconel 718 alloy based around a hyperbolic sine relation is described in this paper. The hyperbolic sine relation with strain dependant parameters is shown to represent the relationship between stress, strain and strain rate over a wide strain range. The valid strain range is sufficient to cover both strain hardening and flow softening behaviour.

Ceramic Cutting Materials and Tools Suitable for Machining High-Temperature Nickel-Based Alloys: A Review

“…Inconel 718 remains one of the most researched grades of nickel-based superalloys in terms of surface integrity aspects [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Other grades of nickel-based superalloys that have received attention among researchers include ME-16 [23][24][25][26][27], RR1000 [28][29][30][31][32][33], IN-100 [34][35][36][37], and FGH95 [36][37][38][39], produced through powder metallurgy (PM) techniques and Udimet 720LI [38,39] which also find applications in aerospace and automobile industries [40][41][42][43][44][45][46][47][48]. Nimonic 80 A (according to DIN 17,742 its alloy mark is NiCr20TiAl, W.Nr.…”

Comparative studies of hyperbolic sine constitutive models for constant pressure superplastic tests

“…The microstructural part of this model was further developed in 2005 [9]. Zhang in 2004 [16] returned to Sellar's model and related the values of the exponential parameter to the α and m parameters. In 2006, Bonet [17] proposed a slight modification of the previous model where the exponential affects the hyperbolic sine function and not its argument.…”

Hyperbolic Sine Representation of a Constitutive Equation for Superplastic Forming Grade Inconel 718

“…The geometric envelope of the test specimens was rectangular with a gauge length, width and thickness of 30, 10 and 1 mm respectively. The actual tests were stepped strain rate tests, where the superimposed stain rate was 1.5 times the underlying strain rate [12][13][14]. The main purpose of stepped strain rate tests is to provide sufficient data to determine the strain rate sensitivity index, m.…”