Constitutive analysis and processing map for hot working of a Ni-Cu alloy

Ebrahimi, Ghanbar; Momeni, Amir; Abbasi, S.M.; Monajatizadeh, H

doi:10.1007/s12540-013-1003-8

Cited by 28 publications

(9 citation statements)

References 15 publications

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“…In contrast to pure Ni, recent investigations have shown that Ni-30Cu (Monel400) is mostly softened by a sluggish continuous DRX (CDRX). 2 Unlike DDRX, which often leads to a fast flow softening, CDRX proceeds with the gradual evolution of substructure and therefore leads to a steady flow softening. 2,19 Therefore, the slow progress of CDRX seems to be responsible for the gradual decrease in Q d of Ni-30Cu in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…As aforementioned, this difference stems from the dissimilar dynamic softening mechanisms of the materials. 2,[17][18][19] It has been well known that materials with higher strain rate sensitivity parameter (m 5 @ln r/@ln _ e) have more resistance against flow localization. 25 As m } 1/n, larger n values increase the risk of flow localization especially at high strains.…”

Section: Resultsmentioning

confidence: 99%

“…This anomalous behavior reflects a change in the mechanism of microstructural evolution as the strain rate exceeds 0.01 s À1 . Recently, Ebrahimi et al 2 found that the mechanism of flow softening changes from CDRX to DDRX when the strain rate exceeds 0.01 s À1 . This change particularly accelerates the rate of dynamic softening and therefore decreases the deformation resistance and the apparent activation energy.…”

Section: Resultsmentioning

confidence: 99%

“…Due to the fact that Q d depends on the deformation resistance, its value is calculated by using different constitutive descriptions of flow stress. [1][2][3][4][5] The value of Q d strongly depends on the material characteristics, which is particularly controlled by the mechanism of dynamic softening, dynamic recovery (DRV), or dynamic recrystallization (DRX). As a matter of fact, there is a relationship between the stacking fault energy (SFE) and the deformation resistance or Q d .…”

Section: Introductionmentioning

confidence: 99%

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The physical interpretation of the activation energy for hot deformation of Ni and Ni–30Cu alloys

Momeni

2016

J. Mater. Res.

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Hot compression tests on pure Ni and Ni-30Cu at 950-1150°C and strain rates of 0.001-1 s À1 were performed to identify the physical interpretation of the apparent activation energy (Q d ). For pure Ni, Q d was constant and identical to that of the self-diffusion. However, for Ni-30Cu, it decreased steadily with strain. The value of Q d was separated into thermal and mechanical parts. The thermal part was necessary to propel diffusion. For pure Ni, the mechanical part was zero at low and medium strain rates of 0.001-0.1 s À1 and the self-diffusion was the controlling mechanism. However, at 1 s À1 , both the thermal and mechanical parts were needed to provide Q d . For Ni-30Cu, Q d was greater than that for the interdiffusion of Ni and Cu. The value of mechanical part decreased with increasing temperature and strain rate. Although the thermal parts for pure Ni and Ni-30Cu were nearly identical, the mechanical part for the latter was considerably higher. The difference was attributed to the strengthening effect of Cu atoms and the sluggish dynamic softening with respect to pure Ni.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The physical interpretation of the activation energy for hot deformation of Ni and Ni–30Cu alloys

Momeni

2016

J. Mater. Res.

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“…As shown in Figure 3(c), it was observed that the value of n for 5CrNiMoV steel presented a rising trend on the whole with temperature rising, which was probably for the increase in rate of DRX with temperature increasing. Many investigations indicated that this difference stemmed from the dissimilar dynamic softening mechanisms of the materials [25,29].…”

Section: (B))mentioning

confidence: 99%

Evolution of Dynamic Recrystallization in 5CrNiMoV Steel during Hot Forming

Wang

2020

Advances in Materials Science and Engineering

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The dynamic recrystallization (DRX) behavior of 5CrNiMoV steel was investigated through hot compression at temperatures of 830–1230°C and strain rates of 0.001–10 s−1. From the experimental results, most true stress-strain curves showed the typical nature of DRX that a single peak was reached at low strains followed by a decrease of stress and a steady state finally at relatively high strains. The constitutive behavior of 5CrNiMoV steel was analyzed to deduce the operative deformation mechanisms, and the correlation between flow stress, temperature, and strain rate was expressed as a sine hyperbolic type constitutive equation. Based on the study of characteristic stresses and strains on the true stress-strain curves, a DRX kinetics model was constructed to characterize the influence of true strain, temperature, and strain rate on DRX evolution, which revealed that higher temperatures and lower strain rates had a favorable influence on improving the DRX volume fraction at the same true strain. Microstructure observations indicated that DRX was the main mechanism and austenite grains could be greatly refined by reducing the temperature of hot deformation or increasing the strain rate when complete recrystallization occurred. Furthermore, a DRX grain size model of 5CrNiMoV was obtained to predict the average DRX grain size during hot forming.

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Hot Deformation Behavior and Microstructural Evolution of High Nitrogen Martensitic Stainless Steel 30Cr15Mo1N

Feng

Jiao

et al. 2017

steel research int.

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Hot deformation behavior of high nitrogen martensitic stainless steel 30Cr15Mo1N is investigated by isothermal compression tests at the temperature range of 900-1250 8C and the strain rate range of 0.01-10 s À1 . The results indicate that the activation energy of this alloy (503.5 kJ mol À1 ) is higher than that of conventional martensitic stainless steels. The developed Arrhenius-type constitutive equation considering strain compensation can predict flow stress of 30Cr15Mo1N with good consistency. The critical conditions for initiation of dynamic recrystallization (DRX) are determined based on the strain hardening rate versus flow stress curves. The DRX is inhibited and grain size decrease with increasing strain rate from 0.01 to 1 s À1 . However, the fraction of DRX increased and grain size coarsened when strain rate is further increased to 10 s À1 . Cr-rich M 23 C 6 and M 2 N precipitated at grain boundaries at lower temperatures, which can effectively pin grain boundaries and, thereby retard or even inhibit the process of DRX. In addition, dislocations tangled and piled up around precipitates, thereby hindering dislocation movement. The influence of precipitates on DRX can be eliminated due to their dissolution at higher temperatures.

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Constitutive analysis and processing map for hot working of a Ni-Cu alloy

Cited by 28 publications

References 15 publications

The physical interpretation of the activation energy for hot deformation of Ni and Ni–30Cu alloys

The physical interpretation of the activation energy for hot deformation of Ni and Ni–30Cu alloys

Evolution of Dynamic Recrystallization in 5CrNiMoV Steel during Hot Forming

Hot Deformation Behavior and Microstructural Evolution of High Nitrogen Martensitic Stainless Steel 30Cr15Mo1N

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