The innovation potential of ECAP techniques of severe plastic deformation

Рааб, Г. И.

doi:10.1088/1757-899x/63/1/012009

Cited by 7 publications

(5 citation statements)

References 6 publications

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“…The material with a UFG structure was produced in Ufa State Aviation Technical University using equal-channel angular pressing (ECAP) combined with the Conform process [7]. A rod with the CG structure was processed through a total of six passes at 200 °C using a die with an angle of 120° between the two channels and processing route B C .…”

Section: Materials and Experimental Methodsmentioning

confidence: 99%

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Strain-Rate Dependence of Compressive Yield Strength of Titanium Grade 4 with Coarse-Grained and Ultrafine-Grained Structures: Experimental Results and Theoretical Calculation

Smirnov¹,

Konstantinov

2018

AMR

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The nanocrystalline (NC) and ultrafine-grained (UFG) structures of metallic materials can lead to their extraordinary high strength. However, most of the papers on this topic consider deformation parameters of NC and UFG materials only for the case of quasi-static tensile tests. Characteristics of dynamic strength and fracture of such materials remain unexplored. This paper presents a study of the mechanical behavior of pure titanium Grade 4 with a coarse-grained (CG) and UFG structure under uniaxial compression with different strain rates. The UFG structure was provided using the method of equal-channel angular pressing. The dynamic compression was carried out on a setup with the Split-Hopkinson pressure bar. It is found that in the observed range of strain rates 10–3-3×103 s–1, the yield stress of the CG titanium increases by 20%, and does not exceed the yield stress of the UFG titanium. However, the yield stress of the UFG titanium remains close to a quasi-static value. It is shown that these strain-rate dependencies of the yield strength can be predicted by the incubation time approach. The calculated curves show that at strain rates above 104 s–1 the yield stress of the CG titanium becomes higher than the yield strength of the UFG titanium.

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Section: Materials and Experimental Methodsmentioning

confidence: 99%

“…Material parameters are given in Table 1. A more detailed description of the processing regimes, the properties and the structure of the produced titanium can be found in [1,2,7].…”

Section: Materials and Experimental Methodsmentioning

confidence: 99%

Strain-Rate Dependence of Compressive Yield Strength of Titanium Grade 4 with Coarse-Grained and Ultrafine-Grained Structures: Experimental Results and Theoretical Calculation

Smirnov¹,

Konstantinov

2018

AMR

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“…This is important, since it is known that the die‐set geometry for the ECAP‐PC technique has a noticeable influence on the force processing parameters, flow homogeneity, as well as the contact forces of the “material‐tool” couple …”

Section: Channels Intersection Angles Selectionmentioning

confidence: 99%

Modeling of Metal Flow during Processing by Multi‐ECAP‐Conform

2015

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This article presents the results of a computer modeling study of a new technique of severe plastic deformation called Multi-ECAP-Conform, ensuring a high level of strain value e i ! 3 per one processing pass of a billet from an Al alloy. The main feature of this technique is multi-stage successive shear straining of a long-length billet under the conditions of equal-channel angular pressing (ECAP) via the Conform mode. The main area of investigation is the study of the effect of the geometry of channels and channels intersection angles on the homogeneity of the strained state, all other conditions being equal. A rational combination of the channels geometry has been established that provides for a homogeneous strained state of billets and allowable force conditions of processing.

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“…Severe plastic deformation (SPD) is one of the most attractive methods of thermomechanical treatment used for structure refinement [7][8][9][10][11]. In their turn, the most promising SPD method for production of bulk UFG billets from Ti-Ni SMA is equal channel angular pressing (ECAP) [12][13][14][15][16]. The best combination of properties in Ti-Ni SMA can be achieved after formation of completely nanocrystalline structure (60-80 nm) [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of quasi-continuous ECAP with various channel intersection angles on the structure formation, mechanical and functional properties of Ti-Ni shape memory alloys

Karelin

Khmelevskaya

Komarov

et al. 2020

METAL 2020 Conference Proeedings

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Influence of quasi-continuous ECAP with channel intersection angles of 110 and 120° on the structure formation and properties of Ti-50.1 at% Ni shape memory alloy was studied and compared. The structure was studied using X-ray diffraction analyses and transmission electron microscopy. The mechanical properties were determined by the uniaxial tensile and hardness tests. The maximum completely recoverable strain and temperatures of reverse martensitic transformation were estimated by a thermomechanical method using a bending mode for strain inducing. After ECAP with channel intersection angle of 120° for 3 passes at 400 °C a mixed ultrafine-grained structure with high density of free dislocations and incompletely equiaxed structural elements size of about 130-150 nm is formed. In comparison, after ECAP with channel intersection angle of 110° an ultrafine-grained structure with deformation bands elongated in the direction perpendicular to the sample axis, consisting of the less uniform equiaxed and ellipsoid structural elements with the size of about 50-150 nm is obtained. After both studied ECAP regimes samples have relatively high values of hardness (220 HV) and strength characteristics (σy = 850/1000 MPa, σB = 1040/1020 MPa, 120/110°). Maximum completely recoverable strain of 7.1 % is obtained after ECAP with channel intersection angle of 110°, and post-deformation annealing at 400 °C, 1 h.

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The innovation potential of ECAP techniques of severe plastic deformation

Cited by 7 publications

References 6 publications

Strain-Rate Dependence of Compressive Yield Strength of Titanium Grade 4 with Coarse-Grained and Ultrafine-Grained Structures: Experimental Results and Theoretical Calculation

Strain-Rate Dependence of Compressive Yield Strength of Titanium Grade 4 with Coarse-Grained and Ultrafine-Grained Structures: Experimental Results and Theoretical Calculation

Modeling of Metal Flow during Processing by Multi‐ECAP‐Conform

Influence of quasi-continuous ECAP with various channel intersection angles on the structure formation, mechanical and functional properties of Ti-Ni shape memory alloys

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