Wyniki wyszukiwania - BazTech

1

Mechanical properties of ultra-fine grain titanium

Greger M., Widomska M., Kander L.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 40, nr 1

33-40

EN

Purpose: The main goal of the presented paper was to describe deformation behaviour of the commercial purity titanium during the ECAP method. Attention was paid particularly on reached mechanical properties of above mentioned material. Design/methodology/approach: Design of experiments rested in extrusion at temperature in range from room temperature up to 280°C. The way of approach was planned in investigation of imposed strain accumulation ability. Among used methods for determination of intended aims were tensile tests, TEM, SEM. Findings: Depending on imposed strain (e = 2 up to 8) was found that mechanical properties (namely tensile strength) have increased up to 960 MPa. Research limitations/implications: Developed ECAP process enables controlling morphology of microstructural constituents and workability of commercially pure titanium. Practical implications: Obtained findings may be used in process of preparing materials for medical application such as dental application where is very important factor their sensitivity to strain. Originality/value: Value of paper is mainly in observed findings that can be used in determination of process conditions at submicro or ultra-fine crystalline materials.

2

Influence of change of direction of deformation at ECAP technology on achieved UFG in AlMn1Cu alloy

Rusz S., Malanik K., Dutkiewicz J., Cizek L., Skotnicova I., Hluchnik J.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 35, nr 1

21-28

EN

Purpose: of this paper is to extend a complex evaluation of aluminium alloy, which requires very often knowledge of behaviour of deformation at the ECAP process and achieved strengthening, intensity of deformation and very fine structure. These factors have influence on the mechanical properties and formability. Presented knowledge expresses very important information for exploitation of this alloy. Design/methodology/approach: The methods determining the dependencies of force on the route during the ECAP process were used. Achieved values were directly plotted on PC. Findings: Conclusions of this work consisted in determination of structure and mechanical properties of this alloy. Research limitations/implications: Achieved hardness and microstructure of this alloy will be determined by new research. Practical implications: The results may be utilized for determination of a relation between structure and properties of the investigated alloy in the process of manufacturing. Originality/value: These results contribute to complex evaluation of properties of the AlMn1Cu alloy, namely in the light of achievement of very fine - grained structures and corresponding mechanical and forming properties. The results of this paper are determined for research workers – in order to increase efficiency of the process of severe plastic deformation.

3

Increase of efficiency of the ECAP technology at grain refinement of the alloy AlMn1Cu

Rusz S., Malanik K., Kedron J.

Archives of Materials Science and Engineering

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2008

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Vol. 34, nr 1

52-56

EN

Purpose: The foundation of the resolved problem consists of verification of influence of temperature and also geometry of the ECAP tool on obtaining of required amount of deformation which substantially influences grain size. Research was realised with use of the alloy AlMn1Cu. Verification concerned influence of change or route of deformation on amount of deformation aimed at obtaining of required grain refinement. Design/methodology/approach: At the first stage of solution mathematical simulation was used for determination of conditions for obtaining the required amount of material deformation. Experimental part of the work was then made on the basis of results of the mathematical simulation. Findings: Route of deformation was changed by deflection of horizontal part of the ECAP channel by 10 and 20°. Obtained results were compared with conventional ECAP process without deflection of the channel. Increased efficiency of the ECAP process was confirmed unequivocally. Practical implications: Practical application of the obtained results at forming of the given alloy in the company AlInvest Bridlicna will bring economy of forming operations, as well as operations of heat treatment of that alloy. Originality/value: The obtained results will be verified by designing of new device enabling forming of strip of sheet. This type of alloy is used for production of strip of sheet by technology of successive rolling to the required thickness with required mechanical properties with preservation of the required formability.

4

Symulacja numeryczna procesów SPD

Olejnik L., Rosochowski A.

Prace Naukowe Politechniki Warszawskiej. Mechanika

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2007

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z. 216

107--112

PL

Wzrost roli obróbki plastycznej w kreowaniu właściwości materiałów przejawia się rosnącym znaczeniem procesów SPD. Są one na razie stosowane głównie do rozdrabniania ziarna na potrzeby badawcze. Brak jest bowiem wydajnych metod, które można zastosować w skali przemysłowej. Przy poszukiwaniu odpowiednich rozwiązań korzysta się z symulacji numerycznych. Podstawowym kryterium oceny przydatności jest badanie rozkładów odkształceń, które mają decydujący wpływ na równomierność rozwoju mikrostruktury przerabianego materiału. W pracy pokazano wykorzystanie metody elementów skończonych do przewidywania zdolności wybranych metod SPD do kumulowania odkształcenia plastycznego, niezbędnego dla uzyskania odpowiedniego rozdrobnienia ziarna. Symulacje numeryczne prowadzono w celu określenia optymalnego kształtu roboczych powierzchni narzędzi. Najwięcej uwagi poświęcono badaniu procesu ECAP, który realizowano przy użyciu kanału kątowego z wieloma zakrętami, a więc w warunkach zapewniających wysoką wydajność wytwarzania drobnoziarnistej struktury. Wyznaczano pożądany kształt i wymiary przekroju poprzecznego wsadu oraz optymalizowano profil kanału. Szczególną uwagę poświęcono analizie wpływu kształtu kanału na jednorodność odkształcenia plastycznego w osiowym przekroju wzdłużnym przeciskanego wsadu. Rozkłady odkształcenia obliczano za pomocą pakietu ABAQUS/Explicit stosując modele płaskie i przestrzenne. Wyniki analiz posłużyły jako wytyczne do budowy matryc do przeciskania, które z powodzeniem sprawdzono przy wytwarzaniu struktur UFG w stopach aluminium.

EN

Severe plastic deformation (SPD) is a new discipline of metal forming technology, which is used to produce an ultrafine grained (UFG) structure and improve properties of metals. There are many SPD processes being proposed but none of them has been used on an industrial scale yet. Finite element method (FEM) is an invaluable tool, which can help understand the mechanics of these processes and make them more industrially feasible. It can also assist in developing new processes. The present paper will show a few case studies based on FEM analyses of SPD processes.