Zjemňování zrna protlačované hořčíkové slitiny AZ31 procesem Ecap

Extruded Mg – 3%Al – 1% Zn (AZ31) magnesium alloy was subjected to ECAP (Equal Channel Angular Pressing) processing at 523 K (250 °C). At the processing temperature of 523 K, fine grains with the average grain size of 2 – 3 μm are formed as a result of dynamic recrystallization originated by fine Mg17Al12 (γ) phase particles having 200 nm diameter dynamically – precipitated during ECAP processing. Microstructural evolution during ECAP was studied systematically using optical microscope and transmission electron microscope.Protlačená hořčíková slitina Mg – 3%Al – 1%Zn (AZ31) byla zpracována procesem ECAP (úhlové protlačování rovnostranným kanálem) realizovaného při teplotě 523 K (250 °C). Při teplotě 523 K bylo dosaženo zjemnění průměrné velikosti zrna 2 - 3 μm, které bylo dosaženo dynamickou rekrystalizací jemné γ faze Mg17Al12 s průměrnou velikostí 200 nm. Vývoj mikrostruktury během ECAP byl systematicky studován na optickém mikroskopu a využitím transmisní elektronové mikroskopie

Study of the Properties of Selected Mg Alloys Formed by ECAP Process

Import 05/08/2014Diplomová práce se zabývá vlivem technologií SPD na mechanické vlastnosti vybraných druhů hořčíkových slitin. Teoretická část této práce obsahuje výčet nejčastěji aplikovaných metod využívajících extrémní plastické deformace za účelem zjemnění výsledné struktury a dosažení nadstandardních mechanických vlastností. Praktická část publikace je zaměřena na realizaci protlačení Mg slitin AZ31 a AZ61 tvářecím nástrojem ECAP, dále je zkoumán vliv vstupního tepelného zpracování T4 na výslednou strukturu a mechanické vlastnosti. Výsledky získané z experimentálních prací jsou dále podrobně rozebrány v závěrečné části práce.Master thesis examines the influence of SPD technologies on the mechanical properties of selected types of magnesium alloys. The theoretical part of the thesis contains a list of the most frequently applied methods based of extreme plastic deformation with goal the obtain good grain refinement of selected alloys with superior mechanical properties. The practical part of the thesis is focused on the realization extrusion process of AZ31 and AZ61 alloy by ECAP process. In the next part of thesis is performed the analyze of influence of input heat treatment T4 on the final structure and mechanical properties. The results obtained of experiments are discussed in final part of thesis.345 - Katedra mechanické technologievýborn

Mechanické vlastnosti oceli DC01 tvářené metodou DRECE

The main goal of the paper is a review of current achieved results given by processing of steel DC01 by DRECE (Dual Rolls Equal Channel Extrusion) forming process, whose prototype equipment has been put in service in the end of 2009 at VŠB – Technical University of Ostrava, Faculty of Mechanical Engineering and Department of Mechanical Technology. The paper analyses the effect of the DRECE forming process on the mechanical properties and deep – drawing sheet metal formability of the steel DC01.Příspěvek uvádí současné výsledky ze zpracování oceli DC01 tvářecím procesem DRECE, jehož prototype byl na konci roku 2009 uveden do provozu pod záštitou VŠB – Technické university Ostrava, Fakulty strojní, Katedry mechanické technologie. Příspěvek analyzuje vliv tvářecí metody DRECE na mechanické vlastnosti a hlubokotažnost oceli DC01

Study of the microstructure, tensile properties and hardness of AZ61 magnesium alloy subjected to severe plastic deformation

Hot extruded (EX) AZ61 magnesium alloy was processed by the twist channel angular pressing (TCAP) method, which combines equal channel angular pressing (ECAP) and twist extrusion (TE) processes and significantly improves the efficiency of the grain refinement process. Both the initial hot extruded AZ61 alloy and the alloy after completion of TCAP processing were examined by using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) and their corresponding micro-tensile testing (M-TT) and hardness testing at room temperature. The results showed that the microstructure of hot extruded alloy was refined well by TCAP due to dynamic recrystallization (DRX) caused by TCAP. The tensile properties, investigated by micro-tensile testing (M-TT), of the AZ61 alloy were significantly improved due to refined microstructure. The highest tensile properties including YS of 240.8 MPa, UTS of 343.6 MPa and elongation of 21.4% of the fine-grained alloy with average grain size below 1.5 mu m was obtained after the third TCAP pass at 200 degrees C using the processing route B-c.Web of Science810art. no. 77

Microstructure evolution of AZ31 magnesium alloy during twist channel angular pressing

Microstructure evolution of hot extruded AZ31 magnesium alloy during twist channel angular pressing was investigated. The grains were refined significantly after one to four passes at 200°C. Microstructure evolution after TCAP processing was investigated using optical microscopy, transmission electron microscopy and electron backscatter diffraction. The results show effect of TCAP process on the achieving the UFG structure with average grain size below 1 μm.Web of Science20236324631

Strengthening of AA5754 aluminum alloy by DRECE process followed by annealing response investigation

In this study, a dual rolls equal channel extrusion (DRECE) process has been applied for improving the mechanical properties of the 5754 alloy. Supplementary experiments involving metallography, electron backscattered diffraction (EBSD), and XRD tests were carried out to evaluate the effect of the DRECE process. XRD analysis showed that the maximum dislocation density was achieved after six DRECE passes, which were accompanied by the formation that is typical for low-strain structures. The increasing dislocation density, as well as grain refinement throughout DRECE deformation, resulted in an increase in the mechanical properties. Annealing of the as-deformed sample resulted in grain growth and strength reduction.Web of Science132art. no. 30

Possibilities of application methods drece in forming of non-ferrous metals

Device “DRECE - Dual Rolls Equal Channel Extrusion” is used for production of metallic materials with very fine grain size (UFG). During the actual forming process the principle of severe plastic deformation is used. Metallic strip with dimensions 57×2×1000 mm is inserted into the device. During the forming process the main cylinder in synergy with the pressure roller extrude the material through the forming tool without any change of cross section of the strip. In this way a significant refinement of grain is achieved by severe plastic deformation. This method is used for various types of metallic materials, non-ferrous metals and their alloys. The DRECE device is also being verified from the viewpoint of achievement of a UFG structure in a blank of circular cross-section (wire) with diameter of ϕ 8 mm × 1000 mm.Web of Science6043015301

Finite element analysis of twist channel angular pressing

The article deals with the analysis of the unconventional pressing process of metallic materials by twist channel angular pressing (TCAP) method. TCAP process is a modification of the equal channel angular pressing (ECAP) forming method, which can be used to prepare bulk materials with an ultra fine-grained structure. Simulation of the TCAP process is an important source of information on the effect of design and technological parameters on the grain refinement efficiency. The TCAP process was simulated using 3D finite element method (FEM).Web of Science20236318631

Investigation of microstructure and mechanical properties of SLM-fabricated AlSi10Mg alloy post-processed using equal channel angular pressing (ECAP)

With the aim of improving the excellent mechanical properties of the SLM-produced AlSi10Mg alloy, this research focuses on post-processing using ECAP (Equal Channel Angular Pressing). In our article, two different post-processing strategies were investigated: (1) low-temperature annealing (LTA) and subsequent ECAP processing at 150 degrees C; (2) no heat treatment and subsequent ECAP processing at 350 degrees C, 400 degrees C and 450 degrees C. The microstructure and mechanical properties of this alloy were analyzed at each stage of post-treatment. Metallographic observations, combined with SEM and EBSD studies, showed that the alloys produced by SLM have a unique cellular microstructure consisting of Si networks surrounding the Al-based matrix phase. Low-temperature annealing (LTA), followed by ECAP treatment, facilitated the microstructural evolution of the alloy with partial breakup of the Si network and observed nucleation of beta-Si precipitates throughout the Al matrix. This resulted in a Vickers microhardness of 153 HV and a yield strength of 415 MPa. The main results show that post-processing of SLM-produced AlSi10Mg alloys using ECAP significantly affects the microstructural evolution and mechanical properties of the alloy.Web of Science1522art. no. 794

Vliv vícenásobné plastické deformace na mechanické vlastnosti a strukturu hliníkových slitin

Article is devoted to analysis of ECAP (Equal Channel Angular Pressing) method, which uses a high degree of deformation to achieve a very fine-grained structure of formed material. Utilization of The ECAP technology enables attainment of required properties of selected materials by using of severe plastic deformation (SPD methods). In the experimental part the influence of the number of passes through forming tool with classical geometry (angle of 90° between channels) was studied to achieve maximum hardening (expressed by deformation resistance and achieved value of hardness HV10). Also the metallographic analysis (detection of achieved grain refinement) was carried out. From comparison of results achieved at both alloys it can be stated that for given forming by ECAP method the EN AW-8006 alloy is preferable, because higher strength degree was obtained by achieving of very fine grained structure. When using the same method of forming by ECAP method the EN AW-2024 alloy has lower hardening and structure refinement.Příspěvek je zaměřen na rozbor vlivu metody ECAP (Equal Channel Angular Pressing), která využívá vysokého stupně vnesené deformace, na dosažení velmi jemnozrnné struktury tvářeného materiálu. Použití technologie ECAP umožňuje docílení požadovaných vlastností u vybraných materiálů použitím vícenásobné plastické deformace (SPD metody, tj. Severe Plastic Deformation). V experimentální části by l zkoumán vliv počtu průchodů tvářecím nástrojem s úhlem mezi kanály 90° na dosažení maximálního zpevnění (vyjádřeného přetvárným odporem a dosaženou hodnotou tvrdosti HV10). Rovněž by la provedena metalografická analýza (zjištění dosaženého zjemnění zrna). Z porovnání dosažených výsledků u obou slitin lze konstatovat, že pro dané procesní parametry tváření metodou ECAP je vhodnější slitina EN AW-8006, protože dosahuje vyšší zpevnění vytvořením jemnozrnné struktury. Při použití shodného způsobu tváření metodou ECAP slitina EN AW-2024 vykazuje nižší zpevnění