Publication detail

Temperature Dependence of Fracture Characteristics ofVariously Heat-Treated Grades of Ultra-High-Strength Steel:Experimental and Modelling

POKLUDA, J. DLOUHÝ, I. KIANICOVÁ, M. ČUPERA, J. HORNÍKOVÁ, J. ŠANDERA, P.

Original Title

Temperature Dependence of Fracture Characteristics ofVariously Heat-Treated Grades of Ultra-High-Strength Steel:Experimental and Modelling

Type

journal article in Web of Science

Language

English

Original Abstract

The temperature dependence of tensile characteristics and fracture toughness of the standardly heat-treated low-alloyed steel OCHN3MFA along with three additionally heat-treated grades was experimentally studied. In the temperature range of ⟨−196; 22⟩ °C, all the additional heat treatments transferred the standard steel from a high- to ultra-high strength levels even with improved tensile ductility characteristics. This could be explained by a reduction of the inclusion content, refinement of the martensitic blocks, ductile retained austenite content, and homogenization of the shape ratio of martensitic laths as revealed by metallographic, X-Ray, and EBSD techniques. On the other hand, the values of the fracture toughness of all grades were found to be comparable in the whole temperature range as the cause of a high stress triaxiality in the pre-cracked Charpy V-notch samples. The values of the fracture toughness of the standard steel grade could be predicted well using the fracture model proposed by Pokluda et al. based on the tensile characteristics. Such a prediction failed in the case of additionally heat-treated grades due to the different temperature dependence of the fracture mechanisms occurring in the tensile and fracture-toughness tests. While the tensile samples fractured in a ductile-dimple mode at all temperatures, the fracture-toughness specimens exhibited a transition from the ductile to quasi-brittle fracture mode with decreasing temperature. This transition could be interpreted in terms of a transfer from the model proposed by Rice and Johnson to the model of Tvergaard and Hutchinson.

Keywords

ultra-high steel grades; tensile characteristics; fracture toughness; temperature dependence; modelling fracture

Authors

POKLUDA, J.; DLOUHÝ, I.; KIANICOVÁ, M.; ČUPERA, J.; HORNÍKOVÁ, J.; ŠANDERA, P.

Released

7. 10. 2021

Publisher

MDPI

ISBN

1996-1944

Periodical

Materials

Year of study

14

Number

19

State

Swiss Confederation

Pages from

1

Pages to

28

Pages count

28

URL

https://www.mdpi.com/1996-1944/14/19/5875

Full text in the Digital Library

http://hdl.handle.net/11012/201772

BibTex

@article{BUT172690,
  author="Jaroslav {Pokluda} and Ivo {Dlouhý} and Marta {Kianicová} and Jan {Čupera} and Jana {Horníková} and Pavel {Šandera}",
  title="Temperature Dependence of Fracture Characteristics ofVariously Heat-Treated Grades of Ultra-High-Strength Steel:Experimental and Modelling",
  journal="Materials",
  year="2021",
  volume="14",
  number="19",
  pages="1--28",
  doi="10.3390/ma14195875",
  issn="1996-1944",
  url="https://www.mdpi.com/1996-1944/14/19/5875"
}