Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7882728 | Acta Materialia | 2012 | 12 Pages |
Abstract
We present the dislocation density and sub-grain size evolution for samples subjected to low cycle fatigue (LCF) loading under various conditions. Interrupted LCF tests have been performed on a cyclic softening bainitic steam turbine rotor steel, 2CrMoNiWV, at total strain amplitudes of ±0.25%, ±0.4% and ±0.7%, strain rates of 0.01 and 0.1% sâ1, and temperatures of 500 and 565 °C. Neutron diffraction experiments have been carried out on these samples, which were evaluated by means of a convolutional multiple whole profile peak shape analysis approach. With this analysis, both dislocation density and sub-grain size evolutions have been determined and compared to the results of transmission electron microscopy (TEM) and scanning TEM (STEM) spot-check evaluations. In addition, the proportions of prevailing dislocation types and the correlation factor of the microstructure have been determined. Finally, the results have been used to establish a phenomenological model describing the relationships between the observed cyclic softening and the evolution characteristics of dislocation density and sub-grain size, as a function of strain amplitude, strain rate and temperature.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
T. Mayer, L. Balogh, C. Solenthaler, E. Müller Gubler, S.R. Holdsworth,