New Mechanistic Models of Creep-Fatigue Interactions for Gas Turbine Components (Final Report)
- Purdue Univ., West Lafayette, IN (United States)
This report documents activities for DE-FE0011796 New Mechanistic Models of Creep-Fatigue Interactions for Gas Turbine Components. As part of the computational mechanics work two rate dependent strain gradient plasticity models are developed. One model is an extension of the Norton model and the other model an extension of the Kocks-Mecking model of unified viscoplasticity. Both models are used to compute results for time dependent deformation problems (gradient creep, void growth, a rotating turbine disk). Detailed numerical verification studies are reported. A plasticity model appointing for the strength differential effect in IN 718 is implemented and employed to analyze indentation experiments. Crack growth simulations are conducted with a cohesive zone model approach combining a rate independent fatigue damage component with a time dependent damage model. Crack growth simulations reported for several combinations of the cohesive zone model with the strain gradient plasticity formulations. Plastic strain gradients lead to local suppression of plastic strain which alters the fatigue crack growth response and crack tip fields locally. It also contributes to the condition of crack deflection and bifurcation at interfaces and interlayers as relevant for the understanding of the crack growth response in certain conditions of IN 718 manufactured additively. IN 718 from a conventional and additive manufacturing route (including a HIP process) are considered. Detailed microstructure characterization is reported. Fatigue crack growth at room temperature and at 650°C are reported for all three material variants, and microscale mechanisms are described.
- Research Organization:
- Purdue Univ., West Lafayette, IN (United States)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE), Clean Coal and Carbon Management
- DOE Contract Number:
- FE0011796
- OSTI ID:
- 1489645
- Report Number(s):
- DOE-PURDUE-0011796
- Country of Publication:
- United States
- Language:
- English
Similar Records
Multi Resolution In-Situ Testing and Multiscale Simulation for Creep Fatigue Damage Analysis of Alloy 617
The roles of yield strength mismatch, interface strength, and plastic strain gradients in fatigue crack growth across interfaces