Hot deformation behavior, dynamic recrystallization, and physically-based constitutive modeling of plain carbon steels

Abstract

The high-temperature deformation behaviors of low and medium carbon steels with respectively 0.06 and 0.5 wt.% C were investigated under strain rate and temperature ranges of 10 -4 -10 -1 s -1 and of 900-1100 °C. Three types of dynamic recrystallization (DRX) flow behaviors were identified, namely single peak, multiple transient steady state, and cyclic behaviors. The normalized critical stress (and strain) for the low and medium carbon steels were about 0.846 (0.531) and 0.879 (0.537), respectively. For both steels, the apparent deformation activation energy and the power of the hyperbolic sine law were found to be near the lattice self-diffusion activation energy of austenite (270 kJ/mol) and 4.5, respectively. As a result, it was concluded that the flow stress of plain carbon steels during hot deformation is mainly controlled by dislocation climb, and based on physically-based constitutive analysis, it was found that carbon has a slight effect on the hot flow stress of plain carbon steels. The significance of the approach used in this work was shown to be its reliance on the theoretical analysis based on the deformation mechanisms, which makes the comparison more reliable.

A Constitutive Equation for the Flow and Densification Behaviors of Powder Metallurgy Fe-0.5C-2Cu Steel at Elevated Temperatures

“…The value of the hot deformation activation energy has been considered to be usually close or equal to the lattice self‐diffusion activation energy. In this work, the value of 267.1 kJ mol −1 for hot deformation activation energy is very close to the lattice self‐diffusion activation energy of austenite, which is reported as 270 kJ mol −1 . This result indicates that the calculation approach of the flow stress of matrix material ( σ 0 ) is reliable.…”

“…In this work, the value of 267.1 kJ mol À1 for hot deformation activation energy is very close to the lattice self-diffusion activation energy of austenite, which is reported as 270 kJ mol À1 . [18,37] This result indicates that the calculation approach of the flow stress of matrix material (s 0 ) is reliable. Combining Equation 9 with the previously obtained Q and n, the value of lnA was calculated as 24.91.…”

Effects of Grain Size on Mechanical Properties and Work‐Hardening Behavior of AISI 304 Austenitic Stainless Steel

“…Tensile testing was carried out at room temperature by a computerized testing machine at the constant cross‐head speed of 1 mm min −1 to obtain engineering stress ( S )–engineering strain ( e ) curves. The values of work‐hardening rate were determined based on , where and are true stress and true strain (logarithmic strain), respectively. The instantaneous (incremental) work‐hardening exponent ( n ) based on the Hollomon equation ( or ) was also considered.…”

A physically-based constitutive model for high temperature deformation of Cu-0.36Cr-0.03Zr alloy

“…Several physical-based constitutive models has been established to describe the work hardening, dynamic recovery and dynamical recrystallization behavior of 42CrMo steel [7], plain carbon steels [8], a nitrogen alloyed ultralow carbon stainless steel [9] a typical nickel-based superalloy (GH4169) [10],Cu-0.4 Mg [11], and 7050 aluminum alloy [12]. Besides, some internal variable thermomechanical constitutive models have been proposed or modified in recent years.…”