Abstract
The mechanical behavior of an aluminum alloy during uniaxial cyclic loading is examined using finite element simulations of aggregates with individually resolved crystals. The aggregates consist of face centered cubic (FCC) crystals with initial orientations assigned by sampling the orientation distribution function (ODF) determined from the measured crystallographic texture. The simulations show that the (elastic) lattice strains within the crystals evolve as the number of cycles increases. This evolution is attributed to the interactions between grains driven by the local plasticity. Under constant amplitude strain cycles, the average (macroscopic) stress decays with increasing number of cycles in concert with the evolution of the lattice strains. Further, the average number of active slip systems also decreases with increasing cycles, eventually reaching zero as the material response becomes totally elastic at the grain level. During much of the cyclic history only a single slip system is activated in most grains. The simulation results are compared to experimental data for the macroscopic stress and for lattice strains in the unloaded state after 1, 30 and 1000 cycles.
Original language | English |
---|---|
Pages (from-to) | 267-281 |
Number of pages | 15 |
Journal | International Journal of Fatigue |
Volume | 25 |
Issue number | 4 |
DOIs | |
Publication status | Published - Apr 2003 |
Externally published | Yes |
Funding
Support for this work has been provided by the Air Force Office of Sponsored Research under Grant #F49620-98-1-0401. Neutron diffraction experiments were performed on a National Research Council (Canada) neutron diffractometer located at the NRU reactor of AECL (Atomic Energy of Canada Limited). The authors thank Dr Ronald Rogge for his assistance in performing these experiments. Computing resources were provided by the Cornell Theory Center. EBSD measurements were performed at the Cornell Center for Materials Research.
Funders | Funder number |
---|---|
Air Force Office of Sponsored Research | 49620-98-1-0401 |
Keywords
- Crystal plasticity
- Cyclic loading
- Lattice strains
- Neutron diffraction
- Polycrystalline material