Correlation of Tensile Properties and Strain Hardening Behavior with Martensite Volume Fraction in Dual-Phase Steels

The strengthening and ductilization of steels are of great importance to weight reduction of vehicles. In this work, the strength-ductility synergy of dual-phase (DP) steels was obtained by properly tailoring the structural heterogeneity, including the distribution and fraction of constituent phases. It was demonstrated that heterogeneous structural DP steels with high volume fraction of martensite (from 64 to 83%) led to a good combination of strength and ductility. Compared with the cold-rolled sheets, the tensile strength and uniform elongation of heterogeneous DP steel increased by 700 MPa (from 1.06 to 1.76 GPa) and 2.7% (from 1.3 to 4%), respectively. The contributions from back stress and effective stress were analyzed by cyclic loading-unloading experiments. The underlying deformation mechanism was discussed based on the results of mechanical test and microstructure observation.

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“…Consequently, the carbon content (C m ) of martensite calculated by the following Eq. (1) [37] exhibits a descending trend, as shown in Fig. 2f.…”

Section: Microstructuresmentioning

confidence: 70%

“…where C and C f represent the carbon content of the steel and ferrite, respectively. The value of C f is set as 0.015 which is the supersaturated limit of carbon in ferrite [37]. Two kinds of ferrite morphologies can be observed in the intercritically annealed DP steels.…”

Section: Microstructuresmentioning

confidence: 99%

A high-strength heterogeneous structural dual-phase steel

et al. 2019

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“…The base material used in this study was a 2 mm thick sheet of DP600 steel, with the chemical composition listed in Table . Details of the manufacturing process of the base material can be found elsewhere . Figure shows the microstructure of DP600 steel.…”

Section: Methodsmentioning

confidence: 99%

“…Details of the manufacturing process of the base material can be found elsewhere. [32] Figure 1 shows the microstructure of DP600 steel. The microstructure was characterized by martensite islands (dark area in Figure 1a) in the ferrite matrix (bright area in Figure 1a).…”

Section: Methodsmentioning

confidence: 99%

Comparison of Microstructure and Tensile Properties of Dual Phase Steel Welded Using Friction Stir Welding and Gas Tungsten Arc Welding

Ashrafi

Shamanian

Emadi

et al. 2018

steel research int.

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In the present research, a comparative study on influence of friction stir welding (FSW) and gas tungsten arc welding (GTAW) processes on the microstructure and tensile properties of dual phase steel welds is carried out. The results indicate that the microstructure of weld metal and inner part of the heat affected zone (HAZ) in the GTA welded sample is composed of coarse bainite, Widmanestatten ferrite and ferrite–carbide (FC) aggregate. The sample welded by FSW exhibits the formation of fine ferrite, FC aggregate, and bainite in the weld nugget and inner part of the HAZ. Microhardness measurements reveal the formation of a softened zone in the subcritical area of the HAZ due to the tempering of the pre‐existing martensite. Both joints show lower tensile strength, tensile elongation and work hardening exponent compared to the base metal (BM), and fail in the softened HAZ during the uniaxial tensile test. However, the joint efficiency, work hardening rate and work hardening exponent of the sample welded by FSW are superior to those for the GTA welded sample. The predominant fracture mechanism for all samples is ductile with dimples on the fractured surfaces.

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“…Based on the linear relationship, the strength of DP steel increases linearly with the increase in V M value, whereas the nonlinear behavior involves with a maximum value of strength at a specific value of V M . [ 29,30 ] Fereiduni et al [ 30 ] showed that the increase in the hardness value with the increase in the amount of V M follows a nonlinear behavior, indicating that the linear relationship like rule of mixtures is not reliable in the DP microstructures.…”

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.

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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.

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Correlation of Tensile Properties and Strain Hardening Behavior with Martensite Volume Fraction in Dual-Phase Steels

Cited by 28 publications

References 35 publications

A high-strength heterogeneous structural dual-phase steel

A high-strength heterogeneous structural dual-phase steel

Comparison of Microstructure and Tensile Properties of Dual Phase Steel Welded Using Friction Stir Welding and Gas Tungsten Arc Welding

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

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