Plastic flow of metals under cyclic change of deformation path conditions

Bochniak, W.; Korbel, A.; Ostachowski, Paweł; Łagoda, М.

doi:10.1016/j.acme.2017.11.004

Cited by 8 publications

(6 citation statements)

References 30 publications

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“…The effect of the dynamic recrystallization of the SPSed AA7075 due to the KOBO extrusion severe deformation process needs to be deeply discussed and analysed. The authors of [27] showed that the cyclic changes in the deformation path during KOBO extrusion led to the crossing of slip and forest dislocations, dislocation dipoles, and point defects. This results in saturation of the crystalline with point defects, a decrease in the migration of self-interstitial atoms, and, consequently, dynamic recrystallization activation energies.…”

Section: Discussionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Spark Plasma Sintered and Severely Deformed AA7075 Alloy

Garbiec¹,

Leshchynsky

García-Junceda

et al. 2021

Metals

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In this paper, the microstructure and mechanical properties of AA7075 with a coarse-fine-grained laminated microstructure produced by spark plasma sintering (SPS) and the cyclic extrusion severe deformation (KOBO) technique were investigated. It was found that an inhomogeneous grain microstructure was formed from coarse and fine grains by the SPS process and then was transformed into a coarse-fine-grained laminated microstructure by means of KOBO extrusion at room temperature. The grain refinement during KOBO extrusion resulted in a fine grained laminated microstructure created due to the formation of low-angle grain boundaries (LAGBs), followed by dynamic recrystallization, leading to high-angle grain boundaries (HAGBs). The EBSD analysis results reveal the formation of a deformed and partially recrystallized ultrafine grain microstructure owing to the generation and development of shear bands during KOBO extrusion. The ultimate tensile strength (UTS) of the AA7075 alloy rose after SPS-KOBO severe deformation up to 422 MPa, with high strains of about 33%. The obtained results clearly show that the SPS-KOBO extrusion technique allows a bimodal laminated fine gradient grain microstructure to be obtained due to deformation and dynamic recrystallization, which result in both high strength and good ductility. The new heterogeneous AA7075 alloys obtained by the SPS-KOBO combined techniques demonstrate that microstructural heterogeneities can assist in overcoming the strength–ductility trade-off.

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Section: Discussionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Spark Plasma Sintered and Severely Deformed AA7075 Alloy

Garbiec¹,

Leshchynsky

García-Junceda

et al. 2021

Metals

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“…Numerical predictions of fitting based on experimental results gives the anisotropic and swift hardening parameters based on CPB06 as shown in table 1. We note that hardening parameters are fitted in this contribution based on the experimental hardening curve of Bochniak et al (2018). Validation of our numerical simulations and fitting of anisotropic parameters based on experimental results allow to predict the ductility limit of the magnesium alloy Mg-Li 4%.…”

Section: Resultsmentioning

confidence: 86%

An Anisotropic Model with Linear Perturbation Technique to Predict HCP Sheet Metal Ductility Limit

Jedidi

Bettaieb

Abed‐Meraim

et al. 2021

Lecture Notes in Mechanical Engineering

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In this paper, hexagonal closed packed (HCP) sheet metal ductility for a viscoplastic material is analyzed by using a linear perturbation technique. It can be used for the analysis of localized necking. This technique is used to perturbate the material behavior in a rate dependent formulation by superimposing a perturbation to the basic flow which its stability or instability is characterized by the increasing or decreasing of the perturbation. Hardening and initial anisotropic parameters are fitted by experimental results from the literature. In this investigation, Cazacu yield function is used to predict the forming limit diagrams (FLDs) of HCP sheet metals. The coupling between analytic perturbation method and the behavior modelling is provided by an efficient implicit algorithm to solve the constitutive equations. After verifications and validations of the numerical simulations from the literature, the ductility limit of a particular HCP magnesium alloy is numerically predicted. A parametric study is presented to analyze the effect of instability and mechanical parameters, viscosity and distortion on the FLDs. Moreover, a comparative study between Marciniak and Kuckzynski ductility approach and linear perturbation technique is done in this contribution.

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“…This might be one of the answers to improving the mechanical properties of materials without using alloy additives that are expensive or of limited availability 16 , 17 . Other innovative ways of metal working studied in recent literature are for instance close die precision forging 18 , continuous extrusion process such as KOBO 19 or accumulative angular drawing process (AAD) 20 . However, before using alternative ways of metal working it is crucial to obtain the batch materials, which is usually provided in semi-continuous or continuous casting processes.…”

Section: Introductionmentioning

confidence: 99%

Prospective cold metal working and analysis of deformation susceptibility of CuMg alloys with high magnesium content

Strzępek,

Zasadzińska

2024

Sci Rep

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Metal alloys designated for cold metal working exhibit much higher strength properties than pure materials due to solid-solution hardening. However, with the increase of mechanical properties its plasticity and workability decreases. Constant development and demand in this area has led to research on many copper alloys, such as copper alloys with high content of magnesium which were never tested before. The limitations regarding cold metal working of CuMg alloys is the main objective of this paper. Here we show that the tested materials exhibit much higher mechanical properties than currently used as electric conductors and carrying-conducting equipment materials such as pure copper, aluminum, M63 brass or CuNiSi alloy. The results were obtained using Hollomon relation, Considére criterion, Gubkin method and hardness measurements. It lead to assessing the prospective cold metal working of CuMg alloys with 2 wt% of magnesium up to 4 wt% of magnesium. The test range included upsetting with 10–50% of cold deformation. It provided the results on evolution of mechanical properties and deformability of tested alloys. Additional information was provided based on the alloys subjected to 50% of strain. The results have proven that as the amount of magnesium increased so did the assessed values, however, it was also linked with increasing friction coefficient. Measured hardness was 2 times higher and calculated Ultimate Tensile Strength (UTS) was even 2.5 times higher in reference to pure copper in the as-cast state. However, with magnesium content at 3.6 wt% or higher, the elevated amount of α + β phase causes brittleness making it impossible to subject these materials to cold metal working processes. We anticipate our assay to be a starting point for more sophisticated models and experimental research concerning cold metal working processes of CuMg alloys of high-strength, which may lead to developing novel and promising set of alloys.

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Plastic flow of metals under cyclic change of deformation path conditions

Cited by 8 publications

References 30 publications

Microstructure and Mechanical Properties of Spark Plasma Sintered and Severely Deformed AA7075 Alloy

Microstructure and Mechanical Properties of Spark Plasma Sintered and Severely Deformed AA7075 Alloy

An Anisotropic Model with Linear Perturbation Technique to Predict HCP Sheet Metal Ductility Limit

Prospective cold metal working and analysis of deformation susceptibility of CuMg alloys with high magnesium content

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