Dislocation Density-Based Constitutive Model for the Mechanical Behavior of Irradiated Cu
Performance degradation of structural steels in nuclear environments results from the development of a high number density of nanometer scale defects. The defects observed in copper-based alloys are composed of vacancy clusters in the form of stacking fault tetrahedra and/or prismatic dislocation loops, which impede dislocation glide and are evidenced in macroscopic uniaxial stress-strain curves as increased yield strengths, decreased total strain to failure, decreased work hardening and the appearance of a distinct upper yield point above a critical defect concentration (neutron dose). In this paper, we describe the development of an internal state variable model for the mechanical behavior of materials subject to these environments. This model has been developed within an information-passing multiscale materials modeling framework, in which molecular dynamics simulations of dislocation--radiation defect interactions, inform the final coarse-grained continuum model. The plasticity model includes mechanisms for dislocation density growth and multiplication and for radiation defect density evolution with dislocation interaction. The general behavior of the constitutive (single material point) model shows that as the defect density increases, the initial yield point increases and the initial strain hardening decreases. The final coarse-grained model is implemented into a finite element framework and used to simulate the behavior of tensile specimens with varying levels of irradiation induced material damage. The simulation results compare favorably with the experimentally observed mechanical properties of irradiated materials in terms of their increased strength, decreased hardening, and decreased ductility with increasing irradiation dose.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15007747
- Report Number(s):
- UCRL-JC-152725; TRN: US200421%%72
- Resource Relation:
- Conference: Materials Research Society Spring Meeting 2003, San Francisco, CA (US), 04/21/2003--04/25/2003; Other Information: PBD: 10 Apr 2003
- Country of Publication:
- United States
- Language:
- English
Similar Records
Nanoindentation of Micrograins in Polycrystals under Multiaxial Stress: Control of Abrupt & Stochastic Plastic Events
Large Scale DD Simulation Results for Crystal Plasticity Parameters in Fe-Cr And Fe-Ni Systems