Computational Micromechanics Modeling of Polycrystalline Superalloys. . .
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Fig. 14 Experimental results and numerical predictions of the cyclic response of Inconel
718 at 400 ◦ C tested under uniaxial tension with R ε = −1. (a) Cyclic stress-strain loops for
ε//ε min = 1.5. (b) Evolution of the stress amplitude, σ/σ 0 , and of the mean stress, σ m /σ 0 ,
with the number of cycles for ε//ε min = 1.5. (c) Idem as (a) for min = 3.5 (d) Idem as
(b) for min = 3.5. Experimental data are given by open circles, while the results provided
by computational homogenization using the crystal plasticity parameters obtained with the inverse
optimization are shown by the broken lines
A second test of the predictive capabilities of the model was attempted by
simulating the cyclic behavior of the same alloy under strain control at R ε = −1
also at 400 ◦ C and three different strain ranges ε//ε min = 1.5, 3, and 3.5. The
experimental cyclic stress-strain curves with R ε = −1 are plotted for two different
cycles (the first one and another at ≈75% of the fatigue life) in Fig. 14a, c for
the tests carried out at ε//ε min = 1.5 and 3.5, respectively. In addition, the
evolution of the stress amplitude, σ , and of the mean stress, σ m , (normalized
by σ 0 ) with the number of fatigue cycles is plotted in Fig. 14b, d for the tests
carried out at ε//ε min = 1.5 and 3.5, respectively. The corresponding numerical
results are plotted in these figures, and the agreement between the experiments
153
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150
200
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(a)
(b)
(c)
(d)
Fig. 14 Experimental results and numerical predictions of the cyclic response of Inconel
718 at 400 ◦ C tested under uniaxial tension with R ε = −1. (a) Cyclic stress-strain loops for
ε//ε min = 1.5. (b) Evolution of the stress amplitude, σ/σ 0 , and of the mean stress, σ m /σ 0 ,
with the number of cycles for ε//ε min = 1.5. (c) Idem as (a) for min = 3.5 (d) Idem as
(b) for min = 3.5. Experimental data are given by open circles, while the results provided
by computational homogenization using the crystal plasticity parameters obtained with the inverse
optimization are shown by the broken lines
A second test of the predictive capabilities of the model was attempted by
simulating the cyclic behavior of the same alloy under strain control at R ε = −1
also at 400 ◦ C and three different strain ranges ε//ε min = 1.5, 3, and 3.5. The
experimental cyclic stress-strain curves with R ε = −1 are plotted for two different
cycles (the first one and another at ≈75% of the fatigue life) in Fig. 14a, c for
the tests carried out at ε//ε min = 1.5 and 3.5, respectively. In addition, the
evolution of the stress amplitude, σ , and of the mean stress, σ m , (normalized
by σ 0 ) with the number of fatigue cycles is plotted in Fig. 14b, d for the tests
carried out at ε//ε min = 1.5 and 3.5, respectively. The corresponding numerical
results are plotted in these figures, and the agreement between the experiments