Wyniki wyszukiwania - Biblioteka Nauki

1

On the mechanical properties and structure of age-hardened AlSi9Cu3 cast alloy

100%

Hurtalova L. , Tillova E.

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tom Vol. 15, no 2

355-362

EN

The paper describes the influence of age-hardening by solution treatment at 515 C with holding time 4 hours, water quenching at 40 C and artificial aging at different temperature 130 C, 150 C and 170 C with different holding time 2, 4, 8, 16 and 32 hours on mechanical properties (strength tensile and Brinell hardness) and changes in the morphology of eutectic Si, Fe-rich and Cu-rich intermetallic phases in secondary (recycled) AlSi9Cu3 cast alloy. The structure with of black-white etching was observed (Dix-Keller, H2SO4). A quantitative study of changes in the morphology of eutectic Si, Cu-rich and Fe-rich phases was carried out using Image Analyzer software NIS-Elements. The analysis of intermetallic phases was performed on SEM using EDX. Mechanical properties were measured in line with STN EN ISO. Age-hardening led to changes in the microstructure including spheroidization and coarsening of eutectic silicon, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases, the dissolution of precipitates and the precipitation of finer hardening phase (Al2Cu), further increase in the hardness and tensile strength in the alloy.

2

Modyfikacja drewna syntetycznymi żywicami z wykorzystaniem energii elektromagnetycznego pola wysokiej częstotliwości

100%

Szutow G.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1980

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tom 231

3

Development and verification of work hardening models for X2CrNiMoN25-7-4 super duplex stainless steel after sigma phase precipitation hardening used for FEM simulations.

84%

Szabracki P. , Bramowicz M. , Lipiński T.

Journal of Power Technologies

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2012

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tom Vol. 92, nr 3

166--173

EN

The aim of this study was to develop numerical work hardening models for super duplex stainless steel X2CrNiMoN25-7-4. Each model accounts for changes caused by the precipitation of a known quantity (0, 20, 35, 38%) of FeCr intermetallic phase (s). The developed models were applied in FEM simulations of tensile tests for various geometries containing the same quantity of the sigma phase. Calculations were performed for two different geometries – flat and round tensile samples. Correlations between experimental and numerically simulated tensile curves were determined using Pearson's correlation coefficient. The obtained results revealed significant correlations (above 0.9955) between numerical and experimental data.

4

Influence of melt temperature on strength parameters of cyclically activated used-up sandmixes containing water-glass, hardened with microwaves

84%

Stachowicz M. , Granat K.

Archives of Civil and Mechanical Engineering

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2015

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tom Vol. 15, no. 4

831--835

EN

The paper presents results of a research on a possibility to apply the innovative, combined with activation of the binder, reclamation process of microwave-hardened moulding sands containing water-glass. The sandmix to be examined, prepared of high-silica sand and the selected water-glass grade 145, was subject to the following cyclical processing stages: mixing the components, compacting, microwave hardening, cooling-down, thermal loading the mould to 800 or 1200 °C, cooling-down to ambient temperature, knocking-out, mechanical dry and wet reclamation, refreshing. After each subsequent cycle of processing the sandmix, used and overheated to various degrees, determined was tensile and bending strength. Analysis of the obtained results indicates that it is possible to activate regenerate of used sandmix containing water-glass, hardened by microwave heating. However, effectiveness of activation in subsequent life cycles of the sandmix is significantly affected by temperature of the casting alloy poured to the mould.

5

A new crystal plasticity model incorporating precipitation strengthening to simulate tensile deformation behavior of AA2024 alloy

84%

Singh L. , Ha S. , Vohra S. , Sharma M.

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2023

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tom Vol. 23, no. 3

art. no. e155, 2023

EN

In this work, a constitutive model is developed by incorporating precipitation strengthening into a dislocation-density-based crystal plasticity (CP) model to simulate the mechanical properties of 2024 aluminium alloy (AA). The proposed model considers the contributions of solid solution strengthening and strengthening from dislocation–precipitate interactions into the total slip resistance along with the forest hardening due to dislocation–dislocation interactions. A term accounting for the multiplication of dislocations due to their interactions with the non-shearable precipitates in the alloy is incorporated in the hardening law. The developed precipitation strengthening-based CP model is implemented into the crystal plasticity finite element method (CPFEM) for simulating the macroscopic mechanical behavior of AA2024-T3 alloy for uniaxial tension over various strain rates. The macroscopic response of the polycrystal representative volume element (RVE) used for simulations is computed using computational homogenization. The effect of meshing resolution on the RVE response is studied using four different mesh discretizations. Predictions of the macroscopic behavior by the developed model are in good agreement with the experimental findings. Additionally, the contribution of model parameters to the total uncertainty of the predicted stress has been assessed by conducting a sensitivity analysis. A parametric analysis with different precipitate radii and volume fractions has been done for finding the effect of precipitates on the macroscopic and localized deformation.

6

Wplyw warunkow miejskich na zdrowotnosc lip [Tilia x europaea] 'Pallida' w Alei Najswietszej Marii Panny w Czestochowie

67%

Bach A. , Frazik-Adamczyk M. , Pawlowska B. , Pniak M.

Roczniki Akademii Rolniczej w Poznaniu. Ogrodnictwo

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2007

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tom 41

11-16

7

Przepusty w infrastrukturze komunikacyjnej – cz. 19. Wyposażenie przejść dla zwierząt – przejścia dolne

67%

Wysokowski A. , Howis J.

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2016

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tom Nr 3

82--88

PL

W nawiązaniu do poprzedniego artykułu z tego cyklu [8], należy przypomnieć, że rozwój infrastruktury komunikacyjnej jest ściśle związany ze zrównoważonym rozwojem, z uwzględnieniem wielu aspektów ekologicznych. Dotyczy to zarówno budowy nowych, jak też modernizacji istniejących dróg kołowych i kolejowych. W tym celu nieodzowna staje się budowa przejść dla zwierząt i przepustów o funkcji zespolonej.

EN

In relation to the previous article from this series, it should be recalled that the development of transport infrastructure is closely related to sustainable development, taking into account many environmental aspects. This applies both new construction as well as modernization of the existing roads and railways. For this purpose, it becomes indispensable to the construction of passages for animals and culverts of complex function.

8

Azotowanie jonowe narzędzi do obróbki plastycznej

67%

Głowacki S. , Majchrzak W. , Majchrzak A.

Inżynieria Powierzchni

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2006

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tom nr 2

31-34

PL

Podano podstawowe informacje o procesie azotowania jonowego, wskazano na jego zalety oraz korzyści z zastosowania. Pokrótce omówiono niektóre badania przeprowadzone w Instytucie Obróbki Plastycznej w Poznaniu (INOP). Przedstawiono wybrane z licznych zastosowań przemysłowych trzy przykłady znacznego zwiększenia trwałości narzędzi do kucia matrycowego w wyniku ich azotowania jonowego w INOP.

EN

Basic information about ion nitriding process and advantages of this kind of thermochemical treatment of metals are given. Results of some investigations carried out at the Metal Working Institute (INOP) in Poznań are reported. Three examples of the prolonged tool life obtained by ion nitriding of drop forging dies selected from the extensiue INOP practice are presented.