Format

Send to

Choose Destination
Materials (Basel). 2016 Oct 14;9(10). pii: E831. doi: 10.3390/ma9100831.

A Constitutive Relationship between Fatigue Limit and Microstructure in Nanostructured Bainitic Steels.

Author information

1
Department of Mechanical and Process Engineering Materials Testing (AWP), University of Kaiserslautern, Gottlieb-Daimler-Straße, Kaiserslautern 67663, Germany. inga.mueller@mv.uni-kl.de.
2
Spanish National Center for Metallurgical Research (CENIM-CSIC), Avda. Gregorio del Amo 8, Madrid E-28040, Spain. rosalia.rementeria@cenim.csic.es.
3
Spanish National Center for Metallurgical Research (CENIM-CSIC), Avda. Gregorio del Amo 8, Madrid E-28040, Spain. fgc@cenim.csic.es.
4
Robert-Bosch GmbH, Materials and Process Engineering Metals, Renningen, Stuttgart 70465, Germany. matthias.kuntz2@de.bosch.com.
5
Asco Industries CREAS, Avenue de France, BP 70045, Hagondange Cedex 57301, France. thomas.sourmail@ascometal.com.
6
Department of Mechanical and Process Engineering Materials Testing (AWP), University of Kaiserslautern, Gottlieb-Daimler-Straße, Kaiserslautern 67663, Germany. kerscher@mv.uni-kl.de.

Abstract

The recently developed nanobainitic steels show high strength as well as high ductility. Although this combination seems to be promising for fatigue design, fatigue properties of nanostructured bainitic steels are often surprisingly low. To improve the fatigue behavior, an understanding of the correlation between the nanobainitic microstructure and the fatigue limit is fundamental. Therefore, our hypothesis to predict the fatigue limit was that the main function of the microstructure is not necessarily totally avoiding the initiation of a fatigue crack, but the microstructure has to increase the ability to decelerate or to stop a growing fatigue crack. Thus, the key to understanding the fatigue behavior of nanostructured bainite is to understand the role of the microstructural features that could act as barriers for growing fatigue cracks. To prove this hypothesis, we carried out fatigue tests, crack growth experiments, and correlated these results to the size of microstructural features gained from microstructural analysis by light optical microscope and EBSD-measurements. Finally, we were able to identify microstructural features that influence the fatigue crack growth and the fatigue limit of nanostructured bainitic steels.

KEYWORDS:

EBSD; Kitagawa diagram; crack growth; critical crack length; crystallography; fatigue limit; nanostructured bainite

Supplemental Content

Full text links

Icon for Multidisciplinary Digital Publishing Institute (MDPI) Icon for PubMed Central
Loading ...
Support Center