TY  - JOUR
AU  - Jovanović, Gvozden
AU  - Glišić, Dragomir
AU  - Dikić, Stefan
AU  - Međo, Bojan
AU  - Marković, Branislav
AU  - Vuković, Nikola
AU  - Radović, Nenad
PY  - 2023
UR  - https://ritnms.itnms.ac.rs/handle/123456789/1174
AB  - Two medium-carbon microalloyed steels with a predominant acicular ferrite microstructure were investigated in this study in order to determine the initial micro-crack formation mechanism and the role of acicular ferrite structure in cleavage fracture. In order to ensure cleavage fracture, samples were investigated at −196 ◦C for uniaxial tension and four point bending fracture. Previous investigations have shown that cleavage fracture for steels with a predominant acicular ferrite microstructure has not been initiated by the fracture of coarse TiN particles as in ferrite-pearlite,
bainite, or martensitic microalloyed steels. The average maximal thickness of cementite plates measured in this work is 0.798 µm and 0.966 µm, for V and TiV steel, respectively. The corresponding stress values required for their fracture according to Griffith’s equation are 1970 MPa and 1791 MPa,
respectively. Estimated values of the effective surface energy for the V steel with an average cementite volume fraction of 3.8% range from 40 Jm−2 to 86 Jm−2, and for the TiV steel with an average cementite volume fraction of 18.3% range from 55 Jm−2 to 82 Jm−2. The fracture of coarse cementite plates was found to not to be responsible for the cleavage fracture initiation in case of both steels.
PB  - MDPI
T2  - Materials
T1  - Determining the role of acicular ferrite carbides in cleavage fracture crack Initiation for two medium carbon microalloyed steels
IS  - 22
VL  - 16
DO  - 10.3390/ma16227192
ER  - 

@article{
author = "Jovanović, Gvozden and Glišić, Dragomir and Dikić, Stefan and Međo, Bojan and Marković, Branislav and Vuković, Nikola and Radović, Nenad",
year = "2023",
abstract = "Two medium-carbon microalloyed steels with a predominant acicular ferrite microstructure were investigated in this study in order to determine the initial micro-crack formation mechanism and the role of acicular ferrite structure in cleavage fracture. In order to ensure cleavage fracture, samples were investigated at −196 ◦C for uniaxial tension and four point bending fracture. Previous investigations have shown that cleavage fracture for steels with a predominant acicular ferrite microstructure has not been initiated by the fracture of coarse TiN particles as in ferrite-pearlite,
bainite, or martensitic microalloyed steels. The average maximal thickness of cementite plates measured in this work is 0.798 µm and 0.966 µm, for V and TiV steel, respectively. The corresponding stress values required for their fracture according to Griffith’s equation are 1970 MPa and 1791 MPa,
respectively. Estimated values of the effective surface energy for the V steel with an average cementite volume fraction of 3.8% range from 40 Jm−2 to 86 Jm−2, and for the TiV steel with an average cementite volume fraction of 18.3% range from 55 Jm−2 to 82 Jm−2. The fracture of coarse cementite plates was found to not to be responsible for the cleavage fracture initiation in case of both steels.",
publisher = "MDPI",
journal = "Materials",
title = "Determining the role of acicular ferrite carbides in cleavage fracture crack Initiation for two medium carbon microalloyed steels",
number = "22",
volume = "16",
doi = "10.3390/ma16227192"
}

Jovanović, G., Glišić, D., Dikić, S., Međo, B., Marković, B., Vuković, N.,& Radović, N.. (2023). Determining the role of acicular ferrite carbides in cleavage fracture crack Initiation for two medium carbon microalloyed steels. in Materials
MDPI., 16(22).
https://doi.org/10.3390/ma16227192

Jovanović G, Glišić D, Dikić S, Međo B, Marković B, Vuković N, Radović N. Determining the role of acicular ferrite carbides in cleavage fracture crack Initiation for two medium carbon microalloyed steels. in Materials. 2023;16(22).
doi:10.3390/ma16227192 .

Jovanović, Gvozden, Glišić, Dragomir, Dikić, Stefan, Međo, Bojan, Marković, Branislav, Vuković, Nikola, Radović, Nenad, "Determining the role of acicular ferrite carbides in cleavage fracture crack Initiation for two medium carbon microalloyed steels" in Materials, 16, no. 22 (2023),
https://doi.org/10.3390/ma16227192 . .

TY  - CONF
AU  - Jovanović, Gvozden
AU  - Glišić, Dragomir
AU  - Radović, Nenad
AU  - Patarić, Aleksandra
PY  - 2019
UR  - https://ritnms.itnms.ac.rs/handle/123456789/945
AB  - Stress and strain distribution at the onset of cleavage fracture during fourpoint bending testing at liquid nitrogen temperature of two commercial mediumcarbon V and TiV microalloyed forging steels, with predominantly acicular ferrite structure, was examined using finite element analysis. The finite element models were based on notched four-point bending Griffiths-Owens’s type specimens, while the material mechanical properties data input was based on stress-strain curves obtained by tensile testing at liquid nitrogen temperature. Results of the modeling showed that there were no distinct differences in strain distribution along the distance from the notch tip between the two steel samples, aside from strain magnitude which stems from the differences in stress-strain curves. Based on the recorded load at fracture, the corresponding displacement calculated by finite element analysis was somewhat larger for the V steel. While the TiV steel breaks at crosshead displacement between 0.3 and 0.5 mm, the V steel breaks between 0.6 and 0.9 mm. Plastic strain at the cleavage initiation site for the TiV steel ranges from 0.0595 to 0.1612, while for the V steel these values range from 0.3694 to 0.6338. Observed differences in plastic deformations near the notch root, where cleavage initiation sites were detected, seem to reflect differences in deformation behavior at liquid nitrogen temperature.
Moreover, such difference could be ascribed to the observed differences in structure, primarily in the volume fraction of acicular ferrite. It was concluded that deformations are more uniformly distributed when acicular ferrite is predominant in
the structure of the steel. It could be ascribed to the effect of “gradual yielding” related to the high dislocation density in acicular ferrite, somewhat lower yield stress and higher ductility of the TiV steel with predominantly acicular ferrite structure.
PB  - Belgrade : Association of Metallurgical Engineers of Serbia
C3  - 4th Metallurgical & Materials Engineering Congress of South-East Europe MME SEE 2019
T1  - Finite element analysis of the cleavage fracture in medium carbon V and TiV microalloyed forging steels
EP  - 70
SP  - 70
ER  - 

@conference{
author = "Jovanović, Gvozden and Glišić, Dragomir and Radović, Nenad and Patarić, Aleksandra",
year = "2019",
abstract = "Stress and strain distribution at the onset of cleavage fracture during fourpoint bending testing at liquid nitrogen temperature of two commercial mediumcarbon V and TiV microalloyed forging steels, with predominantly acicular ferrite structure, was examined using finite element analysis. The finite element models were based on notched four-point bending Griffiths-Owens’s type specimens, while the material mechanical properties data input was based on stress-strain curves obtained by tensile testing at liquid nitrogen temperature. Results of the modeling showed that there were no distinct differences in strain distribution along the distance from the notch tip between the two steel samples, aside from strain magnitude which stems from the differences in stress-strain curves. Based on the recorded load at fracture, the corresponding displacement calculated by finite element analysis was somewhat larger for the V steel. While the TiV steel breaks at crosshead displacement between 0.3 and 0.5 mm, the V steel breaks between 0.6 and 0.9 mm. Plastic strain at the cleavage initiation site for the TiV steel ranges from 0.0595 to 0.1612, while for the V steel these values range from 0.3694 to 0.6338. Observed differences in plastic deformations near the notch root, where cleavage initiation sites were detected, seem to reflect differences in deformation behavior at liquid nitrogen temperature.
Moreover, such difference could be ascribed to the observed differences in structure, primarily in the volume fraction of acicular ferrite. It was concluded that deformations are more uniformly distributed when acicular ferrite is predominant in
the structure of the steel. It could be ascribed to the effect of “gradual yielding” related to the high dislocation density in acicular ferrite, somewhat lower yield stress and higher ductility of the TiV steel with predominantly acicular ferrite structure.",
publisher = "Belgrade : Association of Metallurgical Engineers of Serbia",
journal = "4th Metallurgical & Materials Engineering Congress of South-East Europe MME SEE 2019",
title = "Finite element analysis of the cleavage fracture in medium carbon V and TiV microalloyed forging steels",
pages = "70-70"
}

Jovanović, G., Glišić, D., Radović, N.,& Patarić, A.. (2019). Finite element analysis of the cleavage fracture in medium carbon V and TiV microalloyed forging steels. in 4th Metallurgical & Materials Engineering Congress of South-East Europe MME SEE 2019
Belgrade : Association of Metallurgical Engineers of Serbia., 70-70.

Jovanović G, Glišić D, Radović N, Patarić A. Finite element analysis of the cleavage fracture in medium carbon V and TiV microalloyed forging steels. in 4th Metallurgical & Materials Engineering Congress of South-East Europe MME SEE 2019. 2019;:70-70..

Jovanović, Gvozden, Glišić, Dragomir, Radović, Nenad, Patarić, Aleksandra, "Finite element analysis of the cleavage fracture in medium carbon V and TiV microalloyed forging steels" in 4th Metallurgical & Materials Engineering Congress of South-East Europe MME SEE 2019 (2019):70-70.