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Wyszukujesz frazę "81.40.Lm" wg kryterium: Temat


Tytuł:
Developing Superplasticity in Ultrafine-Grained Metals
Autorzy:
Kawasaki, M.
Langdon, T.
Powiązania:
https://bibliotekanauki.pl/articles/1402058.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.20.Hy
81.40.Lm
Opis:
The processing of bulk metals through the application of severe plastic deformation provides an opportunity for achieving exceptional grain refinement with grain sizes typically lying in the submicrometer or even the nanometer range. Provided these small grains are reasonably stable at elevated temperatures, these ultrafine-grained metals will exhibit excellent superplastic properties when pulled in tension at elevated temperatures. Most ultrafine-grained materials have been produced using either equal-channel angular pressing or high-pressure torsion. This paper examines the results for superplasticity reported to date using metallic alloys processed by equal-channel angular pressing and high-pressure torsion, compares the experimental strain rates with those predicted using the theoretical model for conventional superplastic flow and then demonstrates the feasibility of preparing deformation mechanism maps that provide comprehensive information on the flow mechanisms.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 470-478
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modification of Microstructure and Properties of Extruded Mg-Li-Al Alloys of α and α+ β Phase Composition using ECAP Processing
Autorzy:
Dutkiewicz, J.
Rusz, S.
Maziarz, W.
Skuza, W.
Kuc, D.
Hilser, O.
Powiązania:
https://bibliotekanauki.pl/articles/1033018.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
83.50.-v
81.40.Lm
81.20.Fw
Opis:
Two magnesium based alloys containing 4.5 wt% Li and 1.5 wt% Al (alloy 1) and 9 wt% Li and 1.5 wt% Al (alloy 2) were cast under argon atmosphere and hot extruded at 350°C. Microstructure of alloy 1 consisted of hexagonal α phase of average grain size 20 μm and small aluminum rich precipitates being the most probably AlLi₂Mg phase. Alloy 2 in the extruded form consisted of lamellas of α+ β phases of thickness 5-20 μm and length above 100 μm. Significant grain refinement down to about 2 μ m was observed in one-phase hexagonal (hcp) alloy 1 after one pass of ECAP processing with helical component. Two-phase (hcp + bcc) alloy 2 showed higher non-homogeneity after the first equal channel angular pressing pass due to easier deformation of softer bcc phase, while both, α and β phases exhibited low angle grain boundaries. The hardness and the yield strength of the alloys were higher for alloy 1 (68 HV and 205 MPa, respectively) than those of alloy 2 (61 HV and 175 MPa). Subsequent equal channel angular pressing passes were performed at lower extrusion stress. The hardness of both alloys did not change significantly after subsequent equal channel angular pressing passes and revealed tendency to decrease. Two-phase alloy showed superplastic properties already after one equal channel angular pressing pass at 160°C with grain growth after superplastic tensile testing. Single phase hcp alloy did not show such properties after 1 pass, but after a few equal channel angular pressing passes it could be superplastically formed.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1303-1306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recrystallization in Multilayer Al99.99/AlMg3 Laminates Prepared by Accumulative Roll-Bonding
Autorzy:
Cieslar, M.
Poková, M.
Zimina, M.
Veselý, J.
Bajer, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402060.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.40.Ef
81.40.Lm
61.72.Ff
81.40.-z
Opis:
Composite multilayer sheets from Al/AlMg3 with 32 alternating layers of Al and AlMg3 were prepared by accumulative roll-bonding and their thermal stability was studied. Recrystallized 2 mm thick sheets of a commercial twin-roll cast AlMg3 alloy and high purity Al99.99 served as input materials. Electrical resistivity measurements were used for the integral monitoring of solute atoms distribution during annealing. Light optical microscopy was employed for the direct grain-size determination and recrystallization description. Post-mortem electron microscopy observations were performed on as-prepared and annealed specimens and they were combined with in situ heating electron microscopy in order to explain the observed annealing effects. A broadening of Al layers during annealing was observed and related to diffusion of magnesium.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 487-490
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Press Ram Pulsation on Deep Drawability of Dual Phase Steel Sheet
Autorzy:
Olguner, S.
Tolga Bozdana, A.
Powiązania:
https://bibliotekanauki.pl/articles/1031199.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Hy
81.40.Lm
02.70.Dh
Opis:
A study of the influences of press ram pulsation on deep drawability of dual phase steel sheet is presented. General characteristics of deep drawing process, press ram pulsation technique and dual phase steels are briefly discussed. A finite element model is used to evaluate the influence of pulse motion profile of press ram on the thickness reduction of steel sheet and forming load. Commercial finite element software package DEFORM-3D is used for modelling and simulation of cylindrical cup drawing. The effects of superimposed low frequency vibrations of the press ram are investigated. Pulsation amplitudes of 0.5, 0.25, and 0.125 mm are created on the die with the corresponding pulsation frequencies of 5, 10, and 20 Hz. Finite element simulations are carried out using material model of dual phase (DP600) steel, that is one of the most widely used materials in automobile industry, in order to improve crash safety and fuel economy. Results obtained with press ram pulsation are compared with results for the conventional press ram motion and significant effect of proposed method is demonstrated.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 742-745
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Orientation mapping and in situ annealing applied for characterization of changes in aluminium alloys after deformation
Autorzy:
Bieda, M.
Powiązania:
https://bibliotekanauki.pl/articles/1075659.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Hk
81.40.Lm
81.70.-q
Opis:
The paper presents application of combined in situ annealing and orientation mapping technique for investigation the microstructural changes in the aluminium alloy 6013 with bimodal distribution of the second phase particles during recovery and recrystallization processes. Information about grain distribution, misorientation between grains, size and shape of the grains at each stage of recrystallization process were obtained. Complexity of the experimental procedure is defined and discussed in order to avoid artificial results. Although the article described the advantages and disadvantages of those method used in transmission electron microscopy and scanning electron microscopy in the work the results from scanning electron microscopy/electron backscattering diffraction in situ heating experiments are highlighted. Obtained data are in a good agreement with previous transmission electron microscopy and calorimetry studies.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 979-981
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanisms of Plastic Deformation in Ti-Nb-Zr-Ta Based Biomedical Alloys with Fe and Si Content
Autorzy:
Stráský, J.
Harcuba, P.
Horváth, K.
Janeček, M.
Powiązania:
https://bibliotekanauki.pl/articles/1402084.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.40.Cd
81.70.Bt
81.40.Lm
Opis:
Specialized beta titanium alloys containing biocompatible elements (Nb, Zr, Ta) are increasingly considered as a material for orthopaedic implants. In this study, small additions of Fe and Si are used to increase the strength of commercial Ti-35Nb-7Zr-5Ta (TNZT) alloy. Six different advanced alloys with iron content up to 2 wt% and silicon content up to 1 wt% were manufactured by arc melting and hot forging. Flow curves were determined from tensile tests carried out at room temperature. The yield stress is increased from 450 MPa to 700 MPa due to small Fe and Si additions. Fe causes solid solution strengthening exhibited by sharp yield point and significant work hardening. (Ti,Zr)₅Si₃ intermetallic particles further increase the strength via precipitation hardening. An unusual serrated yielding behaviour of benchmark TNZT alloy is caused by twinning as shown by acoustic emission measurement and electron backscattered diffraction analysis.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 574-577
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal Plasticity Treated as a Quasi-Static Material Flow through Adjustable Crystal Lattice
Autorzy:
Kratochvíl, J.
Powiązania:
https://bibliotekanauki.pl/articles/1418490.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.F-
81.40.Lm
83.50.-v
Opis:
Considering high pressure torsion experiments as a motivation, plastic behavior of crystalline solids is treated as a highly viscous material flow through an adjustable crystal lattice. Instead of the traditional decomposition rule considering the deformation gradient as a product of the elastic and plastic parts, the proposed model is based on its rate form: the velocity gradient consists of the lattice velocity gradient and the sum of the velocity gradients corresponding to the slip rates of individual slip systems; the slip strains themselves are not defined in the model. The geometrical changes caused by material flow and the slip strains can be specified a posteriori. Crystal lattice distortions are measured with respect to a lattice reference configuration. In an adopted rigid plastic approximation the lattice distortions are reduced to rotations. Constitutive equations incorporate non-local hardening caused by close range interactions among dislocations.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 482-484
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical View on the Creep Modelling Procedures
Autorzy:
Kloc, L.
Powiązania:
https://bibliotekanauki.pl/articles/1402073.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.Hg
87.10.Kn
81.40.Lm
Opis:
Process of creep deformation is rather complex, consisting of many interconnected subprocesses, mainly: (i) the creep strain itself, based on dislocation mobility as well as grain boundary activity, (ii) development of dislocation substructure (work strengthening and dynamic recovery), (iii) development of phase structure (phase transformations, precipitation, particle coarsening, etc.), and (iv) nucleation and development of voids and microcracks, i.e. creep damage. The creep experiments are time consuming and expensive, moreover, it is not possible to make experiments under the service conditions of particular materials due to very slow creep strain, the process seems to be ideal field for computer modelling. The experimental data are obviously available for the steady conditions only, so the effects of varying conditions during startup or shutdown of the components can be described by modelling. The model of creep deformation is obviously based on the so-called "creep constitutive equation", which should describe the strain rate dependence on stress, temperature and some other variables. Nevertheless, the comprehensive physical description of all the above mentioned processes is still missing. This paper should illustrate the shortcomings of most "creep constitutive equations", confronting them to some experimental results on common structural materials under non-steady loading conditions.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 540-542
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Hot Deformation of CW602N Brass
Autorzy:
Spigarelli, S.
El Mehtedi, M.
Cabibbo, M.
Powiązania:
https://bibliotekanauki.pl/articles/1402139.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
81.05.Bx
81.20.-n
81.40.Lm
Opis:
Alpha brasses (in principle single-phase solid solution alloys containing less than 35% Zn) are usually processed by extrusion, forging or rolling. Although these materials are of widespread use, few detailed studies of the flow behavior of brass at high temperature are available. The hot workability of a CW602N brass (Cu-36.5%Zn-2%Pb) was thus investigated by torsion testing in the temperature range between 550 and 800°C, under equivalent strain rates ranging from 0.01 to 10 $s^{-1}$. The peak flow stress dependence on temperature and strain rate was described by the well-known Garofalo equation, with a stress exponent close to 4 and Q=220 kJ $mol^{-1}$. A considerably larger scatter of the experimental data was observed in the high temperature range. The detailed microstructural analysis of the deformed samples by scanning electron microscopy revealed substantial differences among the samples deformed in the low temperature regime and those torsioned at 750 and 800°C. These differences were analyzed and discussed to rationalize the different mechanical responses observed in the two hot-deformation regimes.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 726-729
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Creep Behaviour of a Zr-1 wt% Nb Alloy at Elevated Temperatures
Autorzy:
Kvapilová, M.
Kuchařová, K.
Kloc, L.
Sklenička, V.
Powiązania:
https://bibliotekanauki.pl/articles/1402075.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.40.Lm
62.20.Hg
81.05.-t
81.70.Bt
Opis:
This paper presents experimental data regarding creep behaviour of a Zr-1 wt% Nb alloy at elevated (623 K) and at high temperatures (873-1123 K) corresponding to loss-of-cooling situation of fuel cladding tubes for nuclear reactors. For an elaboration of methodological procedure and comparison purposes, the tensile creep tests were conducted using both constant stress and constant load over a wide range of applied stress. The substantial differences in the acquired creep data between constant stress and constant load creep testing were found especially at high stresses and large creep strain levels.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 548-551
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic Emission Study of Plastic Instabilities in AlSi1MgMn
Autorzy:
Molnárová, O.
Dobroň, P.
Chmelík, F.
Powiązania:
https://bibliotekanauki.pl/articles/1402161.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.Le
81.40.Lm
62.20.F-
46.32.+x
Opis:
The influence of the strain rate and heat treatment on the occurrence of plastic instabilities in a cast AlSi1MgMn alloy was studied. The samples were uniaxially loaded in compression at various strain rates and at room temperature. The tests were done with concurrent acoustic emission monitoring and the acoustic emission parameters are correlated to the microstructure and to the stress-strain curves in order to better understand the patterns of plastic deformation. All samples exhibited the Portevin-Le Chatelier effect of different types, dependently on the heat treatment and the applied strain rate. The occurrence of the Portevin-Le Chatelier effect is manifested by acoustic emission signals with high amplitudes. Statistical analysis of the acoustic emission signals shows the power-law probability distribution.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 801-804
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Loading Mode on the Evolution of the Dislocation Structure in Magnesium
Autorzy:
Máthis, K.
Gubicza, J.
Csiszár, G.
Čapek, J.
Clausen, B.
Šíma, V.
Lukáš, P.
Powiązania:
https://bibliotekanauki.pl/articles/1402130.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
83.85.Hf
83.60.La
81.40.Lm
Opis:
The evolution of the dislocation structure in randomly textured cast magnesium as a function of loading mode is studied using whole neutron diffraction pattern line profile analysis and elasto-plastic self-consistent modeling. Both the experimental results and the theoretical data indicate the onset of basal slip at low stresses and the key role of prismatic slip in the macroscopic yield. Dependence of the second-order pyramidal slip on the loading mode is revealed.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 700-703
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FEA of Plastic Flow in AZ63 Alloy during ECAP Process
Autorzy:
Kocich, R.
Kursa, M.
Macháčková, A.
Powiązania:
https://bibliotekanauki.pl/articles/1419003.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.20.Hy
81.40.Lm
81.40.Pq
83.50.Ha
Opis:
Magnesium alloys based on Mg-Al-Zn system are very attractive materials in many industries due to their specific properties. One of common forming manners suitable for this kind of material is the application of severe plastic deformation method. This paper is focused on the deformation behavior of AZ63 alloy at equal channel angular pressing process in the temperature range of 250-320°C. For this purpose finite element analysis was used. Main attention was devoted to the influence of processing parameters on the material flow. Among other, changes of the flow during equal channel angular pressing in chosen regions of the pressed samples were monitored. As variables, temperature, friction coefficient, strain rate, φ-angle or back pressure application were chosen. The comparison of the material flow lines at different conditions shows the affecting of material flow. There are obvious considerable differences between regions adjacent to the inner radius and those adjacent to the outer radius. For example in the case μ = 0 the dead zone is delimited by the angle Ψp = 36°, while in the case of friction given by the coefficient μ = 0.04, the value of the angle was Ψp = 26.5°.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 581-587
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dislocation Substructure Evolution during Hydrostatic Extrusion of Al-Mg-Si Alloy
Autorzy:
Chrominski, W.
Lewandowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/1402087.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
61.72.Ff
81.20.Hy
81.40.Ef
81.40.Lm
Opis:
Hydrostatic extrusion is a technique which allows to produce rods with ultrafine grains and unexpectedly enhanced mechanical properties caused by grain refinement. However, the mechanism of such a refinement is not fully understood at this stage. 6xxx aluminium alloys series are usually processed by extrusion. In this study, commercial 6082 aluminium alloy was extruded at ambient temperature in a cooled die in two stages to the true strain of ε =3.2. Such a processing results in a not fully refined microstructure which allows to study different stages of grain refinement. The texture, dislocation substructures and grain refinement were investigated using electron backscatter diffraction and transmission electron microscopy techniques. The results revealed that two main texture components are present in the extruded rods - ⟨111⟩ fiber texture and ⟨001⟩ recrystallized grains. Transmission electron microscopy inspection revealed dislocation structures that can be associated with different stages of plastic deformation according to the low energy dislocation structures hypothesis proposed by Kuhlmann-Wilsdorf.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 585-588
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activation Energy for Grain Growth of the Isochronally Annealed Ultrafine Grained Magnesium Alloy after Hot Extrusion and Equal-Channel Angular Pressing (EX-ECAP)
Autorzy:
Stráská, J.
Stráský, J.
Janeček, M.
Powiązania:
https://bibliotekanauki.pl/articles/1402085.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.fq
81.05.Bx
81.20.Hy
81.40.Lm
81.70.Bt
Opis:
Magnesium alloy AZ31 prepared by hot extrusion and 4 passes of equal-channel angular pressing (EX-ECAP) has ultra-fine grained microstructure with an average grain size of 900 nm. Grain growth is analysed using a general equation for the grain growth and an Arrhenius equation. The calculated value of the activation energy for grain growth differs with the annealing temperature. The fitted value of activation energy for grain growth in the intermediate temperature range (210-400°C) is in accordance with the results of other authors, but it is shown in this study that such value is abnormally low and physically meaningless. More real values of apparent activation energy in this temperature range were calculated from the model assuming a linear increase of activation energy with increasing annealing temperature. Result of this linear model of evolution of activation energy in the temperature range between 210-400°C is expressed by the interval estimation of apparent activation energy values. It is concluded that the evolution of apparent activation energy can be explained by a change in the mechanism underlying the grain boundary migration. In the low temperature range, the grain boundary diffusion is dominant since the material is ultra-fine grained, whereas at higher temperatures, the lattice self-diffusion is more important.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 578-581
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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