Computational Micromechanics Modeling of Polycrystalline Superalloys: Application to Inconel 718

This paper presents a computational micromechanics modeling approach to predict the dynamic modulus of asphalt concrete mixtures. The modeling uses a finite element method combined with the micromechanical representative volume element (RVE) of mixtures and laboratory tests that characterize the properties of individual mixture constituents. The model treats asphalt concrete mixtures as heterogeneous with two primary phases: a linear viscoelastic fine aggregate matrix (FAM) phase and a linear elastic aggregate phase. The mechanical properties of each phase were experimentally obtained by conducting constitutive tests: oscillatory torsion tests for the viscoelastic FAM phase and quasistatic nanoindentation tests for the elastic aggregate particles. Material properties of each mixture phase were then used in the finite element simulation of two-dimensional mixture microstructures obtained from digital image processes of asphalt concrete mixtures. Model simulations were compared with the experimental dynamic moduli of asphalt concrete mixtures. Simulation results indicated that the micromechanical approach based on the mixture microstructure and phase properties could fairly predict the overall mixture properties that are typically obtained from laboratory mixture tests. Furthermore, the RVE dimension of 60 mm might be used to predict the undamaged viscoelastic stiffness characteristics of asphalt concrete mixtures with reduced computing efforts.

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Computational micromechanics modeling of piezoresistivity of carbon nanotube polymer nanocomposites

10.1117/12.923609 ◽

2012 ◽

Cited By ~ 4

Author(s):

Xiang Ren ◽

Gary D. Seidel

Keyword(s):

Carbon Nanotube ◽

Polymer Nanocomposites ◽

Micromechanics Modeling ◽

Computational Micromechanics

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The Nature of Delta Phase Precipitation in Inconel 718

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055916 ◽

1982 ◽

Vol 40 ◽

pp. 724-725

Author(s):

L. S. Lin ◽

C. C. Law

Keyword(s):

Inconel 718 ◽

Base Alloy ◽

High Strength ◽

Physical Metallurgy ◽

Nickel Base Alloy ◽

Phase Precipitation ◽

Weight Percentage ◽

Delta Phase ◽

The Subject ◽

Nickel Base

Inconel 718, a precipitation hardenable nickel-base alloy, is a versatile high strength, weldable wrought alloy that is used in the gas turbine industry for components operated at temperatures up to about 1300°F. The nominal chemical composition is 0.6A1-0.9Ti-19.OCr-18.0Fe-3Mo-5.2(Cb + Ta)- 0.1C with the balance Ni (in weight percentage). The physical metallurgy of IN 718 has been the subject of a number of investigations and it is now established that hardening is due, primarily, to the formation of metastable, disc-shaped γ" an ordered body-centered tetragonal structure (DO2 2 type superlattice).

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