Skip to main content

Advertisement

Log in

On the sensitivity of fracture mechanism to stress concentration configuration in a two-step quenching and partitioning steel

  • Original Paper
  • Published:
International Journal of Fracture Aims and scope Submit manuscript

Abstract

The effect of stress concentration geometry on the fracture behavior and fracture mechanisms of a two-step quenching and partitioning steel consisting of tempered martensite and retained austenite (RA) is investigated using double edge notched tension (DENT) specimens with different notch root radii. The initial notch opening is varied from a fatigue pre-crack to 15 mm radius. The fracture surface consists in flat triangular regions and slant zones. The fracture mode evolves from intergranular brittle fracture to ductile fracture with dimples. The ductile fracture process further changes from internal necking coalescence to a void sheet shear type coalescence when increasing the notch root radius. A similar transition of the fracture behavior is observed along the ligament of the DENT specimen. This change in the fracture mode results from a decrease of the stress triaxiality. The essential work of fracture is equal to \(40\hbox { kJ/m}^{{2}}\). This is small when looking at the large value of the product of ultimate tensile strength and total elongation (\(\sim 25, 000\, \hbox {MPa}{\cdot }\)%). The small fracture toughness is ascribed to an intergranular fracture mode, which results from the distribution of blocky RA islands along the boundaries of martensitic packets and from the large stress concentration near the notch tip. A proper control of both the amount and morphology of RA during microstructure design is thus essential to generate the best compromise between tensile properties and fracture toughness, and to avoid the relatively low toughness and more brittle failure observed when stress triaxiality increases.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10

Similar content being viewed by others

References

Download references

Acknowledgements

This work was funded by ArcelorMittal Global R&D Maizières Products in France. Z.P.X. thanks the “Beijing Institute of Technology Research Fund Program for Young Scholars”.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Zhiping Xiong.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Xiong, Z., Jacques, P.J., Perlade, A. et al. On the sensitivity of fracture mechanism to stress concentration configuration in a two-step quenching and partitioning steel. Int J Fract 224, 101–116 (2020). https://doi.org/10.1007/s10704-020-00448-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10704-020-00448-0

Keywords

Navigation