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Tytuł:
Effect of Strut Thickness on Room and High Temperature Compressive Properties of Block-Type Ni-Cr-Al Powder Porous Metals
Autorzy:
Kang, B.-H.
Park, M.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/355591.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ni-Cr-Al
powder porous metal
strut thickness
high temperature
compressive behavior
Opis:
This study investigated the effect of strut thickness on the room and high temperature compressive properties of block-type Ni-Cr-Al powder porous metals with ~3000 μm pore size manufactured using a new powder process. Two block-type Ni-Cr-Al porous metals with different strut thicknesses were manufactured. The strut thicknesses of two block foams were 340 μm (A) and 383 μm (B), respectively. Room temperature, 500°C, 650°C and 800°C compressive tests were performed. The compressive results identified typical elastic, plateau and densification regions of foam material in all temperature conditions. Regardless of the strut thickness, compressive strength (maximum peak stress) decreased as deformation temperature increased. In all deformation temperature ranges, the compressive strength measured higher in the porous metal with greater strut thickness (B). The high temperature deformation behavior of powder porous metal was confirmed to be affected by the structural factor and microstructural factor of the porous metal. With the findings described above, this study also discussed the high temperature deformation mechanism of the Ni-Cr-Al metal foam based on fracture surfaces after the high temperature compressions.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1329-1334
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manufacturing And High Temperature Oxidation Properties Of Electro-Sprayed Fe-24.5% Cr-5%Al Powder Porous Metal
Wytwarzanie i wysokotemperaturowe utlenianie elektro-rozpylanego porowatego proszku Fe-24.5% Cr-5%Al
Autorzy:
Lee, K-A.
Oh, J-S.
Kong, Y-M.
Kim, B-K.
Powiązania:
https://bibliotekanauki.pl/articles/350912.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
powder porous metal
electro-spray process
electric wire explosion
Fe-24Cr-5Al
high temperature oxidation
porowaty proszek metalu
elektrorozpylanie
utlenianie wysokotemperaturowe
Opis:
Fe-Cr-Al based Powder porous metals were manufactured using a new electro-spray process, and the microstructures and high-temperature oxidation properties were examined. The porous materials were obtained at different sintering temperatures (1350°C, 1400°C, 1450°C, and 1500°C and with different pore sizes (500 μm, 450 μm, and 200 μm). High-temperature oxidation experiments (TGA, Thermal Gravimetry Analysis) were conducted for 24 hours at 1000°C in a 79% N2+ 21% O2, 100 mL/min. atmosphere. The Fe-Cr-Al powder porous metals manufactured through the electro-spray process showed more-excellent oxidation resistance as sintering temperature and pore size increased. In addition, the fact that the densities and surface areas of the abovementioned powder porous metals had the largest effects on the metal’s oxidation properties could be identified.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1169-1173
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Temperature Oxidation Property of SiC Coating Layer Fabricated by Aerosol Deposition Process
Autorzy:
Ham, G.-S.
Kim, S.-H.
Park, J.-Y.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/352142.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silicon carbide
aerosol deposition
coating
high temperature oxidation
Opis:
This study investigated the high temperature oxidation property of SiC coated layer fabricated by aerosol deposition process. SiC coated layer could be successfully manufactured by using pure SiC powders and aerosol deposition on the Zr based alloy in an optimal process condition. The thickness of manufactured SiC coated layer was measured about 5 μm, and coating layer represented high density structure. SiC coated layer consisted of α-SiC and β-SiC phases, the same as the initial powder. The initial powder was shown to have been crushed to the extent and was deposited in the form of extremely fine particles. To examine the high temperature oxidation properties, oxidized weight gain was obtained for one hour at 1000°C by using TGA. The SiC coated layer showed superior oxidation resistance property than that of Zr alloy (substrate). The high temperature oxidation mechanism of SiC coated layer on Zr alloy was suggested. And then, the application of aerosol deposited SiC coated layer was also discussed.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1347-1351
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Heat Treatment on the Microstructure and Tensile Deformation Behavior of Oxide Dispersion Strengthened Alloys Manufactured by Complex Milling Process
Autorzy:
Kim, Y.-K.
Kim, J.-H.
Gwon, J.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/352535.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ball milling
oxide dispersion strengthening
microstructure
tensile deformation behavior
Opis:
This study attempted to manufacture an ODS alloy by combining multiple milling processes in mechanical alloying stage to achieve high strength and fracture elongation. The complex milling process of this study conducted planetary ball milling, cryogenic ball milling and drum ball milling in sequential order, and then the microstructure and tensile deformation behavior were investigated after additional heat treatment. The oxide particles distributed within the microstructure were fine oxide particles of 5~20 nm and coarse oxide particles of 100~200 nm, and the oxide particles were confirmed to be composed of Cr, Ti, Y and O. Results of tensile tests at room temperature measured yield strength, tensile strength and elongation as 1320 MPa, 2245 MPa and 4.2%, respectively, before heat treatment, and 1161 MPa, 2020 MPa and 5.5% after heat treatment. This results indicate that the ODS alloy of this study gained very high strengths compared to other known ODS alloys, allowing greater plastic zones.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1335-1340
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Compression Properties of Fe-Cr-B Alloy Manufactured using Laser Metal Deposition
Autorzy:
Joo, Y.-A.
Yoon, T.-S.
Park, S.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/352075.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fe-Cr-B composite
laser Metal Deposition
bulk type
microstructure
compressive properties
Opis:
Fe-Cr-B alloy is a material with precipitation of boride inside Fe matrix, and it features outstanding hardness and wear resistance properties. However, Fe-Cr-B alloy is a difficult material to process, making it difficult to use as a bulk type structure material which requires delicate shapes. This study attempted to manufacture Fe-Cr-B alloy using a 3D printing process, laser metal deposition. This study also investigated the microstructure, hardness and compression properties of the manufactured alloy. Phase analysis results is confirmed that α-Fe phase as matrix and (Cr, Fe)2B phase as reinforcement phase. In the case of (Cr, Fe)2B phase, differences were observed according to the sample location. While long, coarse, unidirectional needle-type boride phases (~11 μm thickness) were observed in the center area of the sample, relatively finer boride phases (~6 μm thickness) in random directions were observed in other areas. At room temperature compression test results confirmed that the sample had a compression strength is approximately 2.1 GPa, proving that the sample is a material with extremely high strength. Observation of the compression fracture surface identified intergranular fractures in areas with needle-type boride, and transgranular fractures in areas with random borides. Based on this results, this study also reviewed the deformation behavior of LMD Fe-Cr-B alloy in relation to its microstructures.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1459-1462
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manufacturing and Macroscopic Properties of Y2O3 Coating Layer on Ceramic (AlN) Substrate Fabricated by Aerosol Deposition
Autorzy:
Wi, D.-Y.
Ham, G.-S.
Kim, S.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/353052.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aerosol deposition
Y2O3 coating layer
AlN matrix
nano indentation
Opis:
This study attempted to manufacture an Y2O3 ceramic coating layer on a ceramic (AlN) substrate using aerosol deposition (AD) and investigated its macroscopic properties. Pure Y2O3 powder with a polygonal shape and average size of 5.0 μm was used as initial feedstock. Using aerosol deposition with suitable process conditions, an Y2O3 coating layer was successfully fabricated on aluminum nitride (AIN). The thickness of the manufactured coating layer was approximately 10 mm. The coating layer consisted of Y2O3 phase identical to that in the initial powder, and no additional oxides were identified. In regard to the roughness of the Y2O3 coating layer, the average roughness (Ra) measured 1.32 μm, indicating that the surface roughness was relatively even compared to the initial powder size (5 μm). Mechanical properties of the Y2O3 coating layer were measured using nano indentation equipment, and the indentation modulus of the Y2O3 coating layer fabricated by aerosol deposition measured 136.5 GPa. The interface of the coating layer was observed using TEM, and the deposition mechanism of the Y2O3 coating layer manufactured by aerosol deposition was also discussed.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1463-1466
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Heat Treatment on Microstructure and Impact Toughness of Ti-6Al-4V Manufactured by Selective Laser Melting Process
Autorzy:
Lee, K.-A.
Kim, Y.-K.
Yu, J.-H.
Park, S.-H.
Kim, M.-C.
Powiązania:
https://bibliotekanauki.pl/articles/354570.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
selective laser melting
Ti-6Al-4V
microstructure
impact toughness
heat treatment
Opis:
This study manufactured Ti-6Al-4V alloy using one of the powder bed fusion 3D-printing processes, selective laser melting, and investigated the effect of heat treatment (650°C/3hrs) on microstructure and impact toughness of the material. Initial microstructural observation identified prior-β grain along the building direction before and after heat treatment. In addition, the material formed a fully martensite structure before heat treatment, and after heat treatment, α and β phase were formed simultaneously. Charpy impact tests were conducted. The average impact energy measured as 6.0 J before heat treatment, and after heat treatment, the average impact energy increased by approximately 20% to 7.3 J. Fracture surface observation after the impact test showed that both alloys had brittle characteristics on macro levels, but showed ductile fracture characteristics and dimples at micro levels.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1341-1346
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Corrosion Behaviors of Biodegradable Mg-1Zn-1Zr-xSn Alloys Prepared by Powder-In-Tube Rolling
Autorzy:
Zakiyuddin, A.
Lee, K.
Powiązania:
https://bibliotekanauki.pl/articles/356604.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biodegradable Mg alloy
powder-in-tube rolling
corrosion behavior
Opis:
The objective of the present study was to investigate the effects of Sn addition on the mechanical and corrosion properties of Mg-1Zn-1Zr-xSn (x = 1, 2, 3, 4, 5 wt.%) alloys prepared by powder-in-tube rolling (PTR) method. The PTR-treated Mg alloys reached 98.3% of theoretical density. The hardness of the alloy increased with Sn addition. Two main intermetallic phases, Mg2Sn and Zn2Zr3, were formed in the alloys. The Mg2Sn intermetallic particles were observed along the grain boundaries, while the Zn2Zr3 particles were distributed in the Mg matrix. The addition of 1 wt. % Sn caused the corrosion potential to shift toward a more positive value, and the resulting alloy exhibited low corrosion current density.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1467-1471
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predicted small catchment responses to heavy rainfalls with SEGMO and two sets of model parameters
Przewidywane reakcje zlewni rzecznej na wysokie opady przy wykorzystaniu modelu SEGMO z dwoma zbiorami parametrów
Autorzy:
Krajewski, A.
Lee, H.
Hejduk, L.
Banasik, K.
Powiązania:
https://bibliotekanauki.pl/articles/81567.pdf
Data publikacji:
2014
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Opis:
The study tests the ability of hydrological part of SEGMO (SedimentGraph Model), i.e. lumped parametric rainfall-runoff procedure of SEGMO to simulate design storm runoff in a Korean catchment. The aim of the investigation is to predict responses of small catchment of the Jeungpyeong river, located in central part of South Korea, with the area of 133.6 km2, to 100-year rainfall events, applying SEGMO and using two parallel approaches for model parameter estimation. The first approach is based on catchment characteristics and USDA-SCS procedures, which is suitable for ungauged basins, and the other one is based on rainfall-runoff measurements. The way of estimation of model parameters has been demonstrated. Finally, the model outputs are compared. The difference in largest peak discharges obtained from SEGMO with the two sets of model parameters, i.e. when estimated on the base of catchment characteristics and USDA-SCS procedures, and on the base of rainfall-runoff measurements were relatively small, approaching 37%. This investigation can be seen as checking the uncertainties in model parameter estimation and their influence on flood flows.
Powodzie powodują straty społeczne, środowiskowe oraz ekonomiczne. Ryzyko związane z wystąpieniem powodzi wzrasta wraz z obserwowanymi zmianami klimatu i dotyczy coraz szerszego kręgu mieszkańców globu. W związku z tym, politycy, planiści i projektanci potrzebują informacji o skali zjawiska, które może wystąpić. Informacja ta musi być jednocześnie jak najbardziej wiarygodna. W zlewniach obserwowanych hydrologicznie istnieje możliwość zastosowania metod statystycznych w celu oszacowania przepływów maksymalnych prawdopodobnych. Alternatywą w małych zlewniach, gdzie zwykle brak wieloletnich danych pomiarowych, a które są również bardziej podatne na zmiany wpływające na ich reakcje, jest stosowanie modeli opad – odpływ. W pracy przedstawiono zastosowanie modelu SEGMO do wyznaczenia reakcji rolniczo- leśnej zlewni Jeungpyeong, o powierzchni około 134 km2, położonej w centralnej części Korei Południowej na opad prawdopodobny o p = 1% i różnym czasie trwania. Obliczenia wykonano w dwóch wariantach, określając parametry modelu: (1) na podstawie charakterystyki zlewni (jak dla zlewni nieobserwowanej) oraz (2) na podstawie pomiarów opad–odpływ. Przeprowadzone badania potwierdziły użyteczność modelu do symulacji reakcji zlewni na opady maksymalne, wysoką zgodność parametru CN wyznaczania opadu efektywnego, ustalonego jako wartość tablicową z wartości z danych pomiarowych, oraz dobrą zgodność wyników (maksymalnych przepływów) uzyskanych z zastosowania dwóch ww. sposobów ustalenia parametrów modelu. Wskazano na istotne elementy dalszych badań.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation; 2014, 46, 3
0208-5771
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Incorporation of Resonators Into Plenum Window
Autorzy:
Lee, H. M.
Haris, A.
Lim, K. M.
Xie, J.
Lee, H. P.
Powiązania:
https://bibliotekanauki.pl/articles/176744.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
plenum window
Helmholtz resonators
noise pollution
ventilation
Opis:
A plenum window with incorporation of Helmholtz resonators in between two glass panes was tested in a reverberation room. The effects of jagged flap on reducing strength of diffracted sound was also investigated in the present studies where white, traffic and construction noises were examined Turing each set of experiment. When the noise source was located at the central line of the plenum window, the plenum window with Helmholtz resonators was able to mitigate 8.5 dBA, 8.9 dBA and 8.2 dBA of white, traffic and construction noises, respectively, compared with the case of without window. These amounts of noises that attenuated by the plenum window were slightly higher than the case where noise source was diverged 30° away from the plenum window. The effects of jagged flaps on the acoustical performance of the plenum window were negligible. The Helmholtz resonators had the best performance in the frequency region between 900 Hz to 1300 Hz where in this frequency range, the plenum window with Helmholtz resonators was able to attenuate additional 1.7 dBA, 1.9 dBA and 1.6 dBA of white, traffic and construction noises, respectively, compared with the case of without resonators.
Źródło:
Archives of Acoustics; 2018, 43, 4; 739-746
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of shear stress distribution in a 90 degree channel bend
Autorzy:
Lee, S. K.
Dang, T. A.
Le, V. T.
Powiązania:
https://bibliotekanauki.pl/articles/265109.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
zginanie
naprężenie ścinające
erozja
experimental channel
90 degree bend
shear stress
erosion
deposition
Opis:
Shear stress is a key parameter that plays an important role in sediment transport mechanisms; therefore, understanding shear stress distribution in rivers, and especially in river bends, is necessary to predict erosion, deposition mechanisms and lateral channel migration. The aim of this study is to analyze the shear stress distribution near a river bed at 90-degree channel bend using a depth-average method based on experimental measurement data. Bed shear stress distribution is calculated using the depth-averaged method based on velocity components data has been collected from a 3D-ADV device (three-dimensional acoustic doppler velocity) at different locations of a meandering channel. Laboratory experiments have been made at the hydraulic laboratory of the RCRFIDF (Research Center for River Flow Impingement and Debris Flow), Gangneung-Wonju National University, South Korea to provide data for simulating the incipient motion of the riverbed materials and then predicting the river morphological changes in the curved rivers. The calculated results show that the maximum value of shear stress distribution near the riverbed in the different cross sections of the surveyed channel occurs in a 70-degree cross section and occurs near the outer bank. From the beginning of a 40-degree curved channel section, the maximum value of the shear stress occurs near the outer bank at the end of the channel.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 1; 213-220
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of various carbohydrate sources on postprandial glucose, insulin and NEFA concentrations in obese cats
Autorzy:
Mori, A.
Ueda, K.
Lee, P.
Oda, H.
Ishioka, K.
Sako, T.
Powiązania:
https://bibliotekanauki.pl/articles/31194.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Carbohydrate is an important source of energy, which can significantly affect postprandial blood glucose and insulin levels in cats. In healthy animals, this is not a big concern; however, in obese and diabetic animals, this is an important detail. In the present study, the impact of four different carbohydrate sources (glucose, maltose, corn starch, and trehalose) on short-term post-prandial serum glucose, insulin, and non-esterified fatty acid (NEFA) concentrations was investigated with four obese cats. Each of the carbohydrate sources was added to a commercial wet food diet for feeding the animals. A significant difference was observed in postprandial glucose, insulin, and NEFA area under the curve (AUC) values between each carbohydrate source in obese cats. Furthermore, glucose and maltose induced the highest postprandial glucose and insulin AUC values, whereas trehalose induced the lowest postprandial glucose and insulin AUC value amongst all carbohydrate sources, respectively, in obese cats. However, trehalose has a higher risk of inducing side effects, such as diarrhea, as compared to other carbohydrate sources. As such, different carbohydrate sources appear to have a very significant impact on post-prandial glycemia and subsequent insulin requirement levels in obese cats. These results might be useful when selecting a prescription diet for obese or diabetic cats. In addition, maltose appears to be capable of inducing experimentally evoked postprandial hyperglycemia in obese cats, which may serve as a good tool for use to check the impact and effectiveness of newly developed oral hypoglycemic drugs or supplements for cats in future experiments.
Źródło:
Polish Journal of Veterinary Sciences; 2016, 19, 2
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
TEM Observation of Cu and Ag Added Al-Mg-Si Alloy
Autorzy:
Matsumoto, A.
Nejigaki, T.
Lee, S.
Ikeno, S.
Matsuda, K.
Powiązania:
https://bibliotekanauki.pl/articles/1032894.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.40.Cd
68.37.Lp
Opis:
It is well known that Cu and Ag addition on Al-Mg₂Si alloy can enhance its mechanical properties due to solid solution hardening. Several reports are available about the effect of each alloying elements, Cu and Ag, on Al-Mg-Si alloys. In this research, Al-Mg-Si-Cu-Ag alloys have chemical compositions of (1) 0.18Cu-0.18Ag and (2) 0.35Cu-0.35Ag [at.%] fixed Cu/Ag rate of 1.0 are prepared using casting to estimate effects of Cu and Ag amount to precipitation behaviour and mechanical properties. The Vickers microhardness measurement was conducted to estimate mechanical property after ageing treatment microstructure observation was carried out using transmission electron microscopy. In peak-aged at 473 K hardness of each alloys was almost the same, but in peak-aged at 523 K, hardness of 0.35Cu-0.35Ag was higher than 0.18Cu-0.18Ag alloy.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1379-1381
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formation of Tungsten/Ammonium Perchlorate Composites and Their Reaction Kinetics
Autorzy:
Shim, H.-M.
Lee, E.-A.
Kim, J.-K.
Kim, H.-S.
Koo, K.-K.
Powiązania:
https://bibliotekanauki.pl/articles/358373.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
ammonium perchlorate
composite
thermal decomposition
Opis:
The reaction kinetics of tungsten nanoparticles/ammonium perchlorate (W/AP) composites, produced by a spray drying technique, were analyzed and compared with those of neat AP particles and aluminum nanoparticles/AP (Al/AP) composites. The W was found to raise the onset temperature of the thermal decomposition of AP by increasing the activation energy, whereas Al conversely lowered the onset temperature of AP due to the decreased activation energy. From the master plots of kinetic models with the experimental data, the Prout-Tompkins model and the 1-D diffusion controlled model were found to describe the low-temperature decomposition (LTD) and high-temperature decomposition (HTD), respectively, giving remarkable agreement with experimental curves for all heating rates. The presence of W was found to increase the HTD zone width compared with that of neat AP particles and Al/AP composites. Analysis of the average activation energy and pre-exponential factor showed that W increases the energy barrier and the frequency of occurrence of the reaction compared with that of neat AP particles at the LTD state, whereas W decreases both of them at the HTD state. The effect of Al was also shown to be similar to that of W, but the magnitudes of the variation in activation energy and the pre-exponential factor were relatively small.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 4; 703-722
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolution Of Precipitate Morphology During Extrusion In Mg ZK60A Alloy
Ewolucja morfologii wydzieleń podczas wytłaczania stopu Mg ZK60A
Autorzy:
Park, J.
Jung, K. H.
Lee, G. A.
Kawasaki, M.
Ahn, B.
Powiązania:
https://bibliotekanauki.pl/articles/356233.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
magnesium alloy
ZK60A
precipitation
extrusion
stopy magnezu
wydzielenia
wytłaczanie
Opis:
In this study, a continuously casted ZK60A magnesium alloy (Mg-Zn-Zr) was extruded in two different extrusion ratios, 6:1 and 10:1. The evolution of precipitates was investigated on the two extruded materials and compared with that of as-casted material. The microstructural analysis was performed by electron backscatter diffraction and transmission electron microscopy, and the compositional information was obtained using energy-dispersive X-ray spectroscopy. Several distinct morphologies of precipitates were observed, such as dot, rod, and disk shaped. The formation mechanisms of those precipitates were discussed with respect to the heat and strain during the extrusion process.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1423-1426
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 19

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