EBSD study of micromechanisms involved in high deformation ability of DP steels

Saeidi, Navid; Ashrafizadeh, F.; Niroumand, Behzad; Barlat, Frédéric

doi:10.1016/j.matdes.2015.07.134

Cited by 92 publications

(17 citation statements)

References 32 publications

(41 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was in the range of 1800–2400 MPa. By using a similar method, the interface strength was calculated to be 2100 MPa for DP780 steel . This value was rather high compared to ferrite–cementite interface strength in common low carbon steels with interface strengths of 1200–1300 MPa .…”

Section: Resultsmentioning

confidence: 95%

Evaluation of Fracture Micromechanisms in a Fine‐Grained Dual Phase Steel during Uniaxial Tensile Deformation

Saeidi

Ashrafizadeh

Niroumand

et al. 2014

steel research int.

View full text Add to dashboard Cite

Ductile fracture mechanism in fine‐grained high‐strength dual phase steel in sheet form, which incorporated martensite particles in a soft ferrite matrix, was studied through extensive quantitative metallography, scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD) observations of polished sections as well as fracture surfaces analysis of failed specimens. The void characteristics in terms of area fraction, density, and average size were examined as a function of thickness strain in the sectioned specimens. Detailed microstructural analysis revealed that interface decohesion at triple junctions of ferrite–ferrite–martensite was the dominant void nucleation mechanism. EBSD analysis also revealed that void nucleation was predominantly promoted by the increase of ferrite–ferrite grain boundary misorientation with strain, especially at the boundaries incorporating adjacent martensite particles. Moreover, the study of voids nucleation and evolution behavior suggested that ductile fracture in this steel was nucleation controlled such that just before the final fracture incidence, a high density of voids would be nucleated or a sudden accelerated void nucleation could happen. Microscopic observations as well as statistical analysis confirmed this phenomenon.

show abstract

Section: Resultsmentioning

confidence: 95%

Evaluation of Fracture Micromechanisms in a Fine‐Grained Dual Phase Steel during Uniaxial Tensile Deformation

Saeidi

Ashrafizadeh

Niroumand

et al. 2014

steel research int.

View full text Add to dashboard Cite

show abstract

“…[ 6,34,38 ] Deformation of second hard phase martensite within the microstructure of DP steel is considered as a relaxation mechanism. [ 39 ] Therefore, the lower effect of V M on the UTS than the YS can be justified by deformation of low carbon martensite grains and their relaxation effect opposing the strain hardening, on overall deformation behavior.…”

Section: Developments On the Design Of The Microstructurementioning

confidence: 99%

“…So, it is expected that the smaller ferrite grain size would result in the smaller strain gradient, inside the ferrite grains. It was showed that the greater uniformity of strain distribution within the microstructure will result in superior material formability; [ 39 ] the finer grain size would enhance the YS and strain hardening rate of ferrite matrix which, in turn, would lead to rapid transfer of stress to adjacent martensite grains; this would lead to increase in macroscopic strain hardening.…”

Section: Developments On the Design Of The Microstructurementioning

confidence: 99%

Microstructural Modifications of Dual‐Phase Steels: An Overview of Recent Progress and Challenges

Ebrahimi

Saeidi

Raeissi

2020

steel research int.

View full text Add to dashboard Cite

Optimization of the microstructure and its effect on the strength and ductility of the steel is one of the main aspects of the researcher's effort toward production of advanced structural materials. There have been various investigations focusing on the thermomechanical treatment and grain refinement of steel while some researches are dealing with the modification of chemical composition. This article considering major parameters influencing the mechanical properties of steels aims to present an overview of the outstanding achievements in improvement of the dual-phase steels. Following the obtained consensus, some advanced promising microstructural modification strategies are also suggested, which can bring new insights to shed light upon the further enhancement of the mechanical behavior of the dual-phase steels.

show abstract

“…[15][16][17] Ramazani et al 15) reported that the high dislocation density zone in the surrounding of martensite particles was detected using EBSD with kernel average misorientation (KAM) map. Saeidi et al 16) showed that the higher dislocations created within the smaller grains themselves as sub-boundaries. However, there have been few reports about quantitative evaluation of void formation in dispersed cementite steels.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cementite Dispersion on Void Formation Process in Spheroidize-Annealed Steels

Maeda

Shimamura²,

Suzuki

2018

ISIJ Int.

View full text Add to dashboard Cite

The effect of cementite dispersion on ductile fracture was investigated by comparing void formations in different spheroidize-annealed steels. Two types of steels with different grain sizes and interparticle distances were used. Tensile tests of plate specimens were performed in longitudinal direction along the rolling direction. After the tensile tests, the fractured specimens were cut in the middle along the width. The cross sections near the fractured surface were observed using a scanning electron microscope. Voids in the microstructure were observed in five thickness reduction areas corresponding to different strain levels. As a result, the number density of voids increased as the strain increased in both steels. The number density of voids in steel containing large cementite grains was higher for all strain values, and the fraction of long voids in this steel was higher with greater applied high strain. Two types of voids were mainly observed in this study: One was decohesion of the interface between bainitic ferrite and cementite, while the other was cracking of the cementite itself. Void formation was evaluated using electron back scatter diffraction analysis with kernel average misorientation (KAM) as parameter. The obtained KAM values (representing misorientation in crystal grains) increased with increasing strain, and the areas with high KAM values were concentrated locally along cementite in the long spacing cementite steel. Therefore, it was revealed that void formation in steels with large cementite grains and long cementite spacings occurred more easily by the stress applied to cementite.

show abstract

EBSD study of micromechanisms involved in high deformation ability of DP steels

Cited by 92 publications

References 32 publications

Evaluation of Fracture Micromechanisms in a Fine‐Grained Dual Phase Steel during Uniaxial Tensile Deformation

Evaluation of Fracture Micromechanisms in a Fine‐Grained Dual Phase Steel during Uniaxial Tensile Deformation

Microstructural Modifications of Dual‐Phase Steels: An Overview of Recent Progress and Challenges

Effect of Cementite Dispersion on Void Formation Process in Spheroidize-Annealed Steels

Contact Info

Product

Resources

About