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Coupled Thermomechanical Eulerian-Lagrangian Analysis of the KOBO Extrusion Process

Wójcik Marta, Skrzat Andrzej

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

1185--1193

EN

Numerical simulations of the KOBO extrusion process are presented in this paper. The coupled thermomechanical Eulerian-Lagrangian approach was applied for the three-dimensional finite element model. The dynamic explicit Euler forward method was used in numerical calculations. The elastic-plastic Chaboche model assuming isotropic and kinematic hardening under variable temperature conditions was applied to describe the behaviour of the material under cyclic loading. In numerical computations Chaboche material model implemented in commercial software, as well as the proprietary one written as FORTRAN procedure were tested. The numerical results present the stress and strain distributions in the extruded material, as well as an increase of temperature due to the plastic work and friction. The shape of plastic strain zones was verified experimentally. The approach presented in the paper is a promising numerical tool to simulate the KOBO process.

2

The Influence of Deformation Method on the Microstructure and Properties of Magnesium Alloy WE43

Bednarczyk I., Kuc D., Tkocz M., Tomaszewska A.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

1975--1980

EN

The article presents tests results of the influence of deformation methods on the microstructure and properties of alloy WE43. There were direct extrusion tests and extrusion with KoBo method performed. An assessment of the influence of the methods of deformation on the microstructure and the mechanical properties of the achieved rods from alloy WE43 was conducted. There was an analysis of microstructure carried out with the use of light and scanning microscopy techniques in the initial state and after plastic deformation. Static tensile test was conducted in temperature of 350°C at a speed of 0.0001 m·s-1 and microhardness measurements were performed of HV0.2. On the basis of the achieved mechanical tests results it was stated that in the temperature of 350°C for samples deformed with the use of KoBo method there was an effect of superplastic flow found. The value of elongation achieved was 250% which was 3 times higher than in case of classic extrusion (80%).

3

Microstructure and properties of dynamically compressed copper Cu99.99

Leszczyńska-Madej B., Richert M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 39, nr 1

35-42

EN

Purpose: The main object of this study is to establish the influence of dynamic compression on the possibility of microstructure refinement in polycrystalline copper Cu99.99. Design/methodology/approach: Polycrystalline copper Cu99.99 was dynamically compressed on a falling - weight - type impact machine with strain rate ranging from 1.75×102 to 2.7×102 s-1. After deformation, the samples were tested for microhardness and their microstructure was examined by means both optical and electron microscopy. Additionally, the width of microbands observed in the microstructure was statistically evaluate by using mean chord method. The misorientation of selected microstructural elements was determined using proprietary KILIN software. Findings: It was found that to produce materials with nanometric features is not only possible by exertion of severe plastic deformation methods (SPD) but also by deformation with moderate strains and high strain rates. The demonstrated data show, that in some range the amount of deformation and strain rate can be interchangeable parameters causing similar structural effects.n. Practical implications: The results may be utilized for determination of a relation between microstructure and properties of the copper in the process of dynamic compression. Originality/value: The results contribute to evaluation properties of the polycrystalline copper in the light of achievement of fine – grained microstructure. The obtained results indicated that dynamic compression with high strain rate can be an effective method for microstructure refinement, comparable with SPD methods

4

Wykorzystanie zmiennej drogi odkształcania w celu poprawy wlasności plastycznych wyrobów ciągnionych

Wielgus M., Majta J., Łuksza J.

Przegląd Mechaniczny

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2009

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nr 10

41-44

PL

Przedstawiono zastosowanie nowej metody ciągnienia umożliwiającej uzyskania wzrostu własności plastycznych w wyrobach ciągnionych o przekroju kołowym. Główną ideą przedstawionej nowej metody KWC (kątowego wielostopniowego ciągnienia) jest umożliwienie akumulacji dużego odkształcenia plastycznego, znacznie większego od uzyskiwanego w tradycyjnym procesie ciągnienia. Bezpośrednią konsekwencją uzyskanej niejednorodności odkształcenia jest związany z rozwojem mikrostruktury korzystny rozkład własności mechanicznych w wyrobie ciągnionym. Dodatkowo możliwe jest wykorzystanie proponowanego procesu do uzyskiwania znacznego rozdrobnienia mikrostruktury w obszarach przypowierzchniowych oraz poprawa własności wytrzymałościowych bez konieczności stosowania złożonego składu chemicznego i obróbki cieplnej.

EN

New drawing method influence on plastic properties of drawing products with circular section was presented. The main idea of presented method (angular multistage drawing) was storage of plastic deformation - greater than obtained in traditional drawing process. Proximate consequence of obtained inhomogenity of deformation was related to microstructure development distribution of mechanical properties in drawing products. Additionally, described method can be applied to microstructure refinement in subsurface area as well as strength properties improvement without changes in chemical composition and heat treatment.

5

Przyrostowy sposób przeciskania przez kanał kątowy

Olejnik L., Rosochowski A.

Przegląd Mechaniczny

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2009

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nr 10

22-27

PL

W artykule opisano nowy sposób przyrostowego wytwarzania odkształceń ścinających oparty na metodzie ECAP. Wynikająca stąd nowa metoda I-ECAP nadaje się do produkcji metali ultradrobnoziarnistych w postaci półwyrobów o znacznej szerokości i nieskończonej długości. Zidentyfikowano parametry tej metody i drogą symulacji numerycznych wyznaczono ich pożądane wartości.

EN

The new way of incremental generation of shear strains based on ECAP method was described in the paper. New method called IECAP is suitable for production of ultrafine-grained metals in the form of semi-finished products with substantial width and infinite length. Parameters of the method were identified and desirable values of them were determined using numerical simulations.