Journal of Materials Science

, Volume 54, Issue 6, pp 5044–5060 | Cite as

Austempering in low-C steels: microstructure development and nanohardness characterization

  • M. C. Taboada
  • M. R. Elizalde
  • D. Jorge-BadiolaEmail author


The development of multiphase steels to obtain an optimum balance between strength and ductility is a very active topic of research. In particular, carbide-free bainitic steels have shown promising mechanical properties, making them good candidates for replacing well-established first-generation steels in the automotive industry. In this work, a detailed analysis of the microstructures attainable through overaging treatments is tackled in two bainitic steels with different Si contents. The focus has been put onto the mechanical characterization, via nanoindentation, of the phases that are generated as a consequence of the change in the bainitic treatment conditions and the final cooling to room temperature. The results show the suitability of the nanoindentation technique for gaining knowledge about the underlying transformation-related phenomena and for measuring the relative difference in hardness of the various micro-constituents. The latter is a key factor in understanding the origin of the damage in this kind of steels.



This work has been carried out in the framework of the BaseForm project. This project has received funding from the European Union’s Research Fund for Coal and Steel (RFCS) research programme under grant agreement #RFCS-CT-2014-00017. The authors acknowledge Dr. F. Hisker (ThyssenKrupp) and Dr. S.M.C. van Bohemen (Tata Steel) for providing the material used in this work.

Compliance with ethical standards

Conflict of interest

The authors declare that this work is not subjected to any conflict of interest.


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Authors and Affiliations

  1. 1.CeitDonostia/San SebastiánSpain
  2. 2.Universidad de Navarra, TECNUNDonostia/San SebastiánSpain

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