Dislocation substructure evolution in torsion of pure copper

Liu, C. D.; Bassim, M.N.

doi:10.1007/bf02657323

Cited by 16 publications

(2 citation statements)

References 16 publications

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“…Tests of continuous compression of samples on the GLEEBLE 3800 simulator showed that with a decrease in temperature and an increase in the rate of deformation, the deformation value ε m , suitable for the maximum value of the yield stress moves towards greater deformation. This relationship has been confirmed by Liu et al [ 42 ], as well as in the works [ 43 , 44 , 45 ]. The analysis of the shape of the curves shows that in the tested range of hot deformation parameters, the decrease in deformation hardening of the steel significantly depends on the temperature and the rate of deformation.…”

Section: Discussionsupporting

confidence: 70%

Hot Working Behavior in Multiphase Steel with Ti and V

Wojtacha

Opiela

2022

Materials

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This study investigated the effect of hot working conditions on changes in yield stress and the softening degree in the newly developed multiphase steel with Ti and V microadditions. The research was performed on the GLEEBLE 3800 thermomechanical simulator. In order to determine the σ-ε curves, continuous compression tests were carried out. The samples were plastically deformed at temperatures from 900 °C to 1100 °C at the rate of 0.1 s−1, 1 s−1 and 10 s−1. The activation energy of the plastic deformation was 375 kJ·mol−1. The analysis of the shape and course of the curves indicated that the decrease in strain hardening was mainly the result of the continuous dynamic recrystallization process. Two-stage compression with isothermal holding of the samples was also carried out between the two stages of deformation lasting from 1 s to 50 s. The structure of primary austenite was generated using the ARPGE software. The different size of austenite grain is the result of various thermally activated processes—when increasing the strain rate from 0.1 s−1 to 10 s−1, the average grain size of the primary austenite decreases from approx. 16 µm to approx. 6 µm. The time t0.5 needed to form 50% of the austenite fraction recrystallized at 1100 °C is approx. 4 s and extends to approx. 10 s with the reduction in the plastic deformation temperature to 900 °C. The time of complete austenite recrystallization tR, which varies from approx. 50 s to approx. 90 s in the tested temperature range, lengthens even more. The obtained results make it possible to develop thermomechanical treatment technology for the production of forgings from the tested multiphase steel.

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Section: Discussionsupporting

confidence: 70%

Hot Working Behavior in Multiphase Steel with Ti and V

Wojtacha

Opiela

2022

Materials

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“…Figure a and b display that the LDS appears only in one side of the TBs, while Figure c clearly shows that the LDS presents in both sides of the TBs. In essence, the LDS is ultimately the result of dislocation slip and rearrangement of dislocation structures . Due to the different orientation of the two sides of the TBs, the dislocation slip may occur in only one side or both sides under the same torsion condition, which is dependent on the orientations of the two sides during torsion.…”

Section: Resultsmentioning

confidence: 99%

Microstructures and Mechanical Properties of Commercial Hot‐Extruded Copper Processed by Torsion Deformation

Guo

Xiao

et al. 2016

Adv Eng Mater

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Free-end torsion deformation is used for processing copper rod in this work. Both microstructures and mechanical properties of the torsional rods are quantitatively analyzed. The results show that gradient lamellar dislocation substructures (LDS) along the radial direction as the main defects are formed after torsion. The increment of the LDS density, the shrinking of spacing size, and the change of length/ spacing (L/S) ratio of the LDS are all non-monotonic function of torsion revolution. High-density LDS with fine spacing can retain strain hardening capability, which results in good combination of high tensile strength and good ductility in the torsional deformed sample with large number of revolutions. The influence of torsion strain on primary twin boundaries (TBs) in the hot-extruded rod is also discussed. Fig. 4. Statistical measurements of the LDS size and morphology evolutions with increasing torsion strain: (a) distribution of LDS spacing; (b) distribution of length/spacing (L/S) aspect ratios of LDS in the torsional samples with different strains. The results were determined by using of at least five ECCI images for each sample.

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On dislocation link length statistics for strain hardening and recovery during elevated temperature plastic deformation

Shi

Northwood

1995

Phys. Stat. Sol. (a)

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Tensile tests are performed for an AISI 310 type stainless steel over a range of test temperatures and strain rates. The experimental results generally show that the strain hardening behaviour of the 310 stainless steel has two distinctive regions, namely: (i) a low-temperature region, in which strain hardening decreases linearly with strain and is almost independent of the strain rate; and (ii) a high-temperature region (where the temperature is higher than about half of the melting point), in which strain hardening is affected by strain rate, and the strain hardening coefficient increases with an increase in strain rate at a given temperature. For the 310 stainless steel, the low-temperature region is from 298 to about 873 K, and the high-temperature region is above 873 K. The dynamic effects of strain hardening and recovery processes during elevated temperature plastic deformation of the 310 stainless steel are then analyzed by means of dislocation link length statistics. The main findings are: (i) The strain hardening coefficient for an elevated temperature tensile test is given byR/i, where His strain hardening coefficient for low-temperature plastic deformation without recovery, A , a numerical constant about unity, V ( t ) is dependent on dislocation structure during deformation, R recovery rate, and i strain rate; (ii) for steady state deformation, the relationship between flow stress, 0, and dislocation density, @, namely cr = a,Mpb@'iZ, can be deduced from this analysis, where aI is a constant, M the Taylor factor, ,u shear modulus, and b the Burgers vector; (iii) the dislocation annihilation rate, &, has a stronger dependence on stress than recovery rate, R, and strain rate, C,. The dislocation annihilation rate, &, is proportional to the dislocation density, @, in the manner 4, a ern, where rn = 2 to 3 is a constant. Direct comparison of these new results from dislocation link length statistics is made with the experimental results for the 310 stainless steel. Agreement is good between the analysis and the experimental results.') Windsor, Ontario N9B 3P4, Canada. ' ) Now

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Dislocation substructure evolution in torsion of pure copper

Cited by 16 publications

References 16 publications

Hot Working Behavior in Multiphase Steel with Ti and V

Hot Working Behavior in Multiphase Steel with Ti and V

Microstructures and Mechanical Properties of Commercial Hot‐Extruded Copper Processed by Torsion Deformation

On dislocation link length statistics for strain hardening and recovery during elevated temperature plastic deformation

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