Cyclic strain hardening has been observed to be markedly sensitive to microstructural changes in microalloyed steels. Two significantly different microstructures - polygonal ferrite grains of average grain size 10-120 μm and acicular ferrite/upper bainite colonies of dimensions 200-625 μm - were examined in order to determine the influence of each on cyclic strain hardening and related properties. Tests were conducted at temperatures between -150 and 27°C. The cyclic strain hardening exponent, βc, was significantly more sensitive to changes in the size of the polygonal ferrite grains than to changes in the acicular ferrite/upper bainite colony size.
Bibliographical noteFunding Information:
This work was performed at the Sandia National Laboratories supported by the US Department of Energy under contract number DE-AC04-76DPO0789. Partial financial support was further provided under grant number DOE-DE AC02-79ER10433, also from the Department of Energy.
- cyclic hardening
- grain size
- low cycle fatigue
- low temperatures
- microalloyed steels