Abstract
The fatigue crack growth process involves damage accumulation and crack extension. The two sub-processes that lead to fatigue crack extension were quantified separately in a recent model for small fatigue crack growth applicable to engineering alloys. Here, we report the results of an experimental investigation to assess the assumptions of that model. The fatigue striation formation in an aluminum alloy is modeled, and it is verified that the number of cycles required for striation formation is related to the cyclic crack-tip opening displacement. The striation spacing is related to the value of the monotonic crack-tip displacement. It is concluded that extensive crack-tip geometry changes due to plasticity in the aluminum alloy causes a reduction in the slope of the fatigue crack propagation curves. The implications of these results on the fatigue crack propagation lifetime calculations are identified.
| Original language | English |
|---|---|
| Pages (from-to) | 1843-1852 |
| Number of pages | 10 |
| Journal | International Journal of Fatigue |
| Volume | 32 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 2010 |
Funding
The authors thank Prof. J. Wayne Jones and Dr. Xiaoxia Zhu of the University of Michigan for the femtosecond laser machining experiments. The authors also thank Carl Boehlert (Michigan State University) and Peter Blau (ORNL) for reviewing the manuscript. The research at the Oak Ridge National Laboratory’s High Temperature Materials Laboratory was sponsored by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program. A portion of this research was conducted at the SHaRE User Facility, which is sponsored by the Division of Scientific User Facilities, Office of Basic Energy Sciences, US Department of Energy.
| Funders | Funder number |
|---|---|
| Division of Scientific User Facilities | |
| Office of Basic Energy Sciences | |
| US Department of Energy | |
| Office of Energy Efficiency and Renewable Energy | |
| Oak Ridge National Laboratory |
Keywords
- Fatigue crack growth
- Fatigue striations
- Metals and alloys
- Modeling
- Plastic deformation