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Nonlocal damage‐viscoplastic model for high temperature creep of single crystal superalloys
Author(s) -
Trinh Bach Tuyet,
Hackl Klaus
Publication year - 2011
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201110214
Subject(s) - creep , superalloy , viscoplasticity , materials science , dissipation , dislocation , constitutive equation , mechanics , deformation (meteorology) , single crystal , structural material , thermodynamics , composite material , physics , finite element method , nuclear magnetic resonance , microstructure
A new nonlocal damage‐viscoplastic model for high temperature creep of single crystal superalloys is developed. It is based on the variational formulation consisting of free energy, plastic and damage dissipation potentials. Evolution equations for plastic strain and damage variables are derived from the minimum principle for dissipation potentials [1]. The model is capable of describing different stages of creep in a unified way. The evolution of dislocation densities of gamma and gamma prime phases in superalloys incorporates plastic deformation. It results in the time‐dependence of the creep rate in primary and secondary creep. Tertiary creep is taken into account by introducing local and nonlocal damage variables. Herein the nonlocal one is considered as numerical treatment to remove mesh‐dependence. Numerical results and comparisons with experimental data of the single crystal superalloy LEK94 are shown. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)