Analysis of the hysteresis loop in stainless steels II. Austenitic-ferritic duplex steel and the effect of nitrogen

0177742 - UFM-A 20013107 RIV NL eng J - Journal Article
Polák, Jaroslav - Fardoun, F. - Degallaix, S.
Analysis of the hysteresis loop in stainless steels II. Austenitic-ferritic duplex steel and the effect of nitrogen.
Materials Science and Engineering A Structural Materials Properties Microstructure and Processing. Roč. 297, 1/2 (2001), s. 154-161. ISSN 0921-5093. E-ISSN 1873-4936
R&D Projects: GA AV ČR IAA2041704
Institutional research plan: CEZ:AV0Z2041904
Keywords : duplex steel * hysteresis loop * statistical theory
Subject RIV: JL - Materials Fatigue, Friction Mechanics
Impact factor: 0.978, year: 2001

The hysteresis loop of austenitic-ferritic duplex stainless steels, both with different levels of nitrogen, was analyzed using general statistical theory. The plot of the second derivative yields information on the average effective stress and the probability density function of the critical internal stresses, its evolution in cyclic straining and its dependence on the strain amplitude. The probability density function in duplex steels has two peaks, which correspond to the two-phase structure. The position of these peaks plotted vs. fictive stress corresponds very well to the position of the peaks in individual phases. The changes of the effective moduli and the evolution of the effective and internal component of the cyclic stress are reported. The nitrogen has strong effect on the probability density function of the critical internal stresses in austenitic steel. The suppression of the second peak formed in high amplitude straining is discussed in terms of the appearance of planar dislocation structures, which develop due to the presence of nitrogen.
Permanent Link: http://hdl.handle.net/11104/0074657