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Wyświetlanie 1-15 z 1094
Tytuł:
Powłoki ceramiczne Al2O3 otrzymywane w technologii natryskiwania cieplnego plazmowego APS
Ceramic coatings Al2O3 obtained using APS plasma thermal spraying technology
Autorzy:
Iwaniak, Aleksander
Powiązania:
https://bibliotekanauki.pl/articles/36141084.pdf
Data publikacji:
2024
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Ceramiki i Materiałów Budowlanych
Tematy:
natryskiwanie cieplne plazmowe
APS
powłoka Al2O3
zużycie tribologiczne
mikrostruktura powłok
Atmosferic Plasma Spraying
Al2O3 coating
tribological wear
microstructure of coatings
Opis:
W pracy wytworzono ceramiczne powłoki z proszku tlenku aluminium i proszku tlenku aluminium z dodatkiem 5% proszku tlenku tytanu z wykorzystaniem technologii natryskiwania plazmowego ASP. Stwierdzono, że dodatek 5% proszku tlenku tytanu TiO2 do proszku tlenku aluminium Al2O3 powoduje spadek porowatości natryskiwanej powłoki z 5,9 % do 3,5%. Ponadto tlenek tytanu dodany do tlenku aluminium zmniejsza twardość natryskiwanej powłoki z 988 HV0,3 do 935 HV0,3. Wykonane badania zużycia tribologicznego wytworzonych powłok z skojarzeniu z pinem z węglika krzemu SiC wykazały, że dodatek tlenku tytanu powoduje zmniejszenie współczynnika tarcia badanego skojarzenia w warunkach tarcia suchego - współczynnik µ zmalał z wartości µ=0,37 do µ=0,26.
In this work, ceramic coatings were produced from aluminum oxide powder and aluminum oxide powder with the addition of 5% titanium oxide powder using ASP plasma spraying technology. It was found that the addition of 5% titanium oxide TiO2 powder to aluminum oxide powder Al2O3 causes a decrease in the porosity of the sprayed coating from 5.9% to 3.5%. Moreover, titanium oxide added to aluminum oxide reduces the hardness of the sprayed coating from 988 HV0.3 to 935 HV0.3. Tribological wear tests of coatings produced in combination with a SiC silicon carbide pin showed that the addition of titanium oxide causes a reduction in the friction coefficient of the tested combination under dry friction conditions - the μ coefficient decreased from μ=0.37 to μ=0.26.
Źródło:
Szkło i Ceramika; 2024, 75, 1; 1-6
0039-8144
Pojawia się w:
Szkło i Ceramika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The concept of discourse in terms of cognitive linguistics
Autorzy:
Babayeva, Nigar O.
Powiązania:
https://bibliotekanauki.pl/articles/40409777.pdf
Data publikacji:
2024-03-31
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
discourse
text
macrostructure
microstructure
Opis:
At the end of the 20th century, the term discourse, which was justified by European linguists, gained relevance in modern linguistics and gave rise to wider research. The ideas about the discourse in the scientific literature have given impetus to each other and facilitated a wider analysis of this term. In Azerbaijani linguistics, this topic is considered a younger field of science. From this point of view, we decided to conduct research in the mentioned direction. In the article, the types of discourse from the point of view of both structure and functionality, and the problems of its comparison with the text are considered.
Źródło:
Reality of Politics; 2024, 27; 7-17
2082-3959
Pojawia się w:
Reality of Politics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparative Study on Ex-Situ & In-Situ Formed Metal Matrix Composites
Autorzy:
Gobalakrishnan, B.
Rajaravi, C.
Udhayakumar, Gobikrishnan
Lakshminarayanan, P. R.
Powiązania:
https://bibliotekanauki.pl/articles/2203734.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
MMCs
Al-SiC
Al-TiB2
extrusion
heat treatment
mechanical properties
microstructure
Opis:
An attempt has been made to synthesize the aluminium based ex-situ (Al-SiC) and in-situ (Al-TiB2) formed metal matrix composites with varying weight percentage of reinforcement contents such as 4wt.%, 6wt.% and 8wt.%. Synthesized composites were subjected to a cold extrusion process followed by heat treatment according to the ASTM B 918-01 standards. The mechanical properties of in-situ composites were evaluated as per the ASTM guidelines and compared with ex-situ formed composites and base metal properties. Superior properties were noticed in the in-situ formed composites and the mechanical properties such as yield strength, Ultimate tensile strength (UTS) and Hardness for both ex-situ and in-situ composites were found to increase with increasing the reinforcement addition. Cold extruded Al-8 wt.% SiC composite properties such as hardness, yield strength and UTS are 87 RB, 152 MPa, 216 MPa respectively. Whereas, for Al-8 wt.% TiB2 composite, the corresponding properties are 94 RB, 192 MPa, 293 MPa. The morphology of the composites is analysed by Optical and Scanning Electron Microscopic (SEM) whereas presence of reinforcement particles such SiC and TiB2 along with intermetallic phases Mg2Si and Al5FeSi are confirmed by EDX, XRD and Element Mapping analyses.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 171--185
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accounting for the random character of nucleation in the modelling of phase transformations in steels
Autorzy:
Poloczek, Łukasz
Kuziak, Roman
Foryś, Jakub
Szeliga, Danuta
Pietrzyk, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/29519774.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
stochastic model
grain size
phase transformations
dislocation density
cooling of rods
heterogeneity of the microstructure
Opis:
In our earlier work, a stochastic model of multi-stage deformation at elevated temperatures was developed. The model was applied to calculate histograms of dislocation density and grain size at the onset of phase transformation. The histograms were used as input data for the simulation of phase transitions using the traditional deterministic model. Following this approach, microstructural inhomogeneity was predicted for different cooling conditions. The results obtained, showing the effect of dislocation density and inhomogeneity of austenite grain size on the microstructural inhomogeneity of the final product, can be considered reliable as they are based on material models determined in previous publications and validated experimentally. The aim of the present work was to extend the model by taking into account the stochastic nature of nucleation during phase transitions. The analysis of existing stochastic models of nucleation was performed, and a model for ferritic transformation in steels was proposed. Simulations for constant cooling rates as well as for industrial cooling processes of steel rods were performed. In the latter case, uncertainties in defining the boundary conditions and segregation of elements were also considered. The reduction of the computing costs is an important advantage of the model, which is much faster when compared to full field models with explicit microstructure representation.
Źródło:
Computer Methods in Materials Science; 2023, 23, 2; 17-28
2720-4081
2720-3948
Pojawia się w:
Computer Methods in Materials Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza wpływu parametrów napawania laserowego LMD na wybrane właściwości napoin wytworzonych z proszku HS6-5-2c na stali 1.4923
Analysis of influence of LMD laser surfacing parameters on selected properties of surfacings produced from HS6-5-2c powder on 1.4923 steel
Autorzy:
Chrzanowski, Wojciech
Napadłek, Wojciech
Bogdanowicz, Zdzisław
Powiązania:
https://bibliotekanauki.pl/articles/27323998.pdf
Data publikacji:
2023
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
stal 1.4923
proszek stopowy hs6-5-2c
napawanie laserowe LMd
warstwa wierzchnia
geometria napoiny
skład chemiczny
mikrostruktura
twardość
erozja
steel 1.4923
HS6-5-2c alloy powder
LMD laser deposition
surface layer
deposition geometry
chemical composition
microstructure
hardness
erosion
Opis:
W pracy zaprezentowano wyniki badań napoin wytworzonych technologią napawania laserowego LMd (Laser Metal Deposition) z zastosowaniem różnych parametrów wiązki laserowej. na powierzchni podłoży ze stali 1.4923 w kształcie prostopadłościanów wytworzono napoiny wielościegowe z proszków hs6-5-2c o różnym stopniu przykrycia. W ramach prób napawania laserowego wytworzono próbki, na których następnie przeprowadzono badania topografii powierzchni, obserwacje mikrostruktury oraz pomiary twardości w poszczególnych strefach warstwy wierzchniej podłoża, to jest w strefie napoiny, strefie wpływu ciepła (sWc) oraz w strefie materiału rodzimego. obserwacjęi analizę powierzchni napoin oraz mikrostruktury w przekroju poprzecznym próbek po napawaniu LMd zrealizowano z zastosowaniem mikroskopii optycznej ze światłowodową transmisją obrazu. pomiary twardości wykonano, używając twardościomierza Vickersa FLc-50a. na podstawie obserwacji mikroskopowych stwierdzono, że uzyskane napoiny mają regularny i powtarzalny kształt. Ponadto na powierzchniach wytworzonych napoin oraz w strefie wtopienia materiału napoiny z materiałem podłoża nie zauważono występowania wad procesowych. Twardość uzyskanych napoin wynosiła 500-700 hV0,1. Wytworzone na bazie proszku hs6-5-2c napoiny poddano badaniom odporności na erozję, które wykazały znacznie wyższą odporność na zużycie erozyjne (nawet ok. pięciokrotnie) w porównaniu z materiałem podłoża (stal 1.4923) bez napawania.
This paper presents the results of testing surfacings produced by LMd (Laser Metal deposition) laser deposition technology for different laser beam parameters. on the surface layer of rectangular-shaped samples, made of 1.4923 steel, multiwall surfacing was produced from hs6-5-2c powder with different degrees of coverage. as a part of the laser deposition verification and testing, surface topography, microstructure and hardness tests were carried out in the deposition zone, heat affected zone, and the zone of the parent material. The surface of the surfacing and the microstructure in cross-section were observed on an optical microscope with fibre-optic image transmission. Hardness measurements were made in the cross-section of the sample using a Vickers FLc-50a hardness tester. Based on the observations, it was found that the obtained surfacings have a regular and repeatable shape. There were no welding defects on the surfaces of the produced surfacings and in the zone of fusion of the surfacing material with the substrate material. The hardness of the surfacings was obtained in the range of 500-700 hV0.1. The surfacings produced by LMd technology were subjected to erosion resistance tests, which showed significantly higher (about 5 times higher) resistance to erosion wear of the produced surface layers (surfacings based on hs6-5-2c powder) in comparison with the substrate material, i.e., steel 1.4923.
Źródło:
Biuletyn Wojskowej Akademii Technicznej; 2023, 72, 1; 116--130
1234-5865
Pojawia się w:
Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and Improvement of an Industrial Process of Hot Die Forging of an Elongated Forging Tipped with a Joggle with the Use of Numerical Simulation Results
Autorzy:
Hawryluk, Marek
Rychlik, Marcin
Polak, Sławomir
Zwierzchowski, Maciej
Dudkiewicz, Łukasz
Marzec, Jan
Jabłoński, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2201924.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
closed die forging
numerical modelling
yoke type forging
quality of forging
microstructure of forging
Opis:
The article performs an analysis of a hot die forging process of producing an elongated forging ended with a joggle in a double system realized on a crank press Masey 1300 t, in open dies, in 3 operations. The thermomechanical model of the forging process considering the changes in the grain size and the forging material recrystallization was elaborated with the use of the calculation packet Qform 7. In the first place, an in-depth analysis of the currently realized forging technology was made, with a special consideration of the temperature changes in the tools as well as in the formed forging. Next, numerical modelling of the process was carried out, as a result of which the following were obtained: correct filling of the tool impressions by the deformed material, the temperature distributions for the forging and the tools, the plastic deformation distributions (considering the thermally activated phenomena), the changes in the grain size and the forging force courses. The results obtained from FEM enable a thorough analysis of the forging process, including: the effect of the deformation time and temperature on the grain size in the forging material, which was confirmed by the microstructure examination results.
Źródło:
Advances in Science and Technology. Research Journal; 2023, 17, 2; 192--205
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined Effect of CrB2 Micropowder and VN Nanopowder on the Strength and Wear Re-sistance of Fe‒Cu–Ni–Sn Matrix Diamond Composites
Autorzy:
Ratov, Boranbay
Mechnik, Volodymyr
Rucki, Miroslaw
Gevorkyan, Edwin
Kilikevicius, Arturas
Kolodnitskyi, Vasyl
Siemiatkowski, Zbigniew
Umirova, Gulzada
Chałko, Leszek
Józwik, Jerzy
Zhanggirkhanova, Arailym
Chishkala, Vladimir
Korostyshevskyi, Dmytro
Powiązania:
https://bibliotekanauki.pl/articles/2201897.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
diamond composite
electroconsolidation
composite microstructure
adhesion
CrB2
VN nanopowder
micropowder
VN
wear resistance
cutting tools
mining tools
Opis:
The paper presents research results on the enhancement of diamond composites designed for tools application for mining industry, hard rocks cutting, able to withstand harsh conditions under heavy dynamical loads. In the present study, both CrB2 micropowder and VN nanopowder additives were used in proportions up to 5 wt.% and 6 wt.%, respectively, together with the basic matrix composition of 51 wt.% Fe, 32 wt.% Cu, 9 wt.% Ni, and 8 wt.% Sn. Addition of both components, CrB2 and VN, appeared to be ad-vantageous in proportion of 2 wt.% and 4 wt.%, respectively. This composition exhibited the highest relative density of 0.9968, better than that without additives. Similarly, the highest values of compressive strength Rcm and flexural strength Rbm were reached for the composite with the same percentage of CrB2 and VN. Compared to the composite with no addition of CrB2 and VN, Rcm improved by almost 70%, while Rbm by 81%. Additionally, the abovementioned additives enhanced the ability of the matrix to prevent the diamond reinforcement from being torn out of the composite, which is very important under harsh working conditions of the cutting tools. The presence of CrB2 micropowder and VN nanopowder promoted densification of the matrix and adhesion between the diamond grits and the Fe‒Cu–Ni–Sn matrix.
Źródło:
Advances in Science and Technology. Research Journal; 2023, 17, 1; 23--34
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Densification and Magnetic Properties of Fe Powder Compacts According to Heat-Treatment Conditions
Autorzy:
Yoo, Hyo-Sang
Kim, Yong-Ho
Kim, Cheol-Woo
Son, Hyeon-Taek
Powiązania:
https://bibliotekanauki.pl/articles/2203721.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fe powder
heat-treatment
microstructure
density
Opis:
In this study, the effects of heat-treatment conditions of Fe powder compacts on densification, microstructure, strength and magnetic properties were investigated. The prepared Fe powder was compressed in a mold of diameter 20 mm at a pressure of 800 MPa for 30 sec. This Fe powder compact was heat-treated under different atmospheres (air and 90% Ar + 10% H2 and heat-treatment temperatures (300 and 700℃). The Fe powder compacts heat-treated in an Ar+H2 mixed gas atmosphere showed a denser microstructure and higher density than the Fe powder compacts heat-treated in an air atmosphere. Oxygen content in the heat-treatment conditions played a significant role in the improvement of the densification and magnetic properties.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 47--50
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic Behaviour of Selective Laser Melted 316L Steel : Mechanical Properties and Microstructure Changes
Dynamiczne zachowanie próbek ze stali 316L wytworzonych za pomocą metody SLM : właściwości mechaniczne i zmiany mikrostruktury
Autorzy:
Białobrzewski, Paweł
Sienkiewicz, Judyta
Janiszewski, Jacek
Kluczyński, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/27314959.pdf
Data publikacji:
2023
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
microstructure
stainless steel
selective laser melting
additive manufacturing
split Hopkinson pressure bar
mikrostruktura
metoda addytowa
SLM
stal nierdzewna
test dzielonego pręta Hopkinsona
Opis:
316L steel specimens with three different shear zones made by SLM (Selective Laser Melting) were subjected to dynamic tests using the Split Hopkinson Pressure Bar method. The effect of high-speed deformation on changes in microstructure was analyzed. In addition, the stress-strain relationship was determined from the SHPB results. To visualize the deformation process of the specimens during the tests, a camera with a high frame rate was used. It was shown that as the plastic deformation increases, the hardness of the material increases. Microstructural analysis of dynamically loaded areas revealed numerous defects. Twinning was found to be the main deformation mechanism. Large plastic deformation and many other microstructural changes such as shear bands, cracks and martensite nucleation were also observed.
Próbki ze stali 316L z trzema różnymi strefami ścinania wykonane metodą SLM (Selective Laser Melting) poddano testom dynamicznym wykorzystując do tego metodę dzielonego pręta Hopkinsona (Split Hopkinson Pressure Bar). Przeanalizowano wpływ odkształceń o dużej szybkości na zmiany w mikrostrukturze. Ponadto na podstawie wyników badań SHPB wyznaczono zależność naprężenie- odkształcenie. W celu zobrazowania procesu odkształcania próbek podczas badań zastosowano kamerę o dużej częstości klatkowania. Wykazano, że wraz ze wzrostem odkształcenia plastycznego wzrasta twardość materiału. Analiza mikrostrukturalna obszarów obciążonych dynamicznie ujawniła liczne defekty. Stwierdzono, że głównym mechanizmem deformacji jest bliźniakowanie. Zaobserwowano również duże odkształcenia plastyczne i wiele innych zmian mikrostruktury, takich jak pasma ścinania, pęknięcia i zarodkowanie martenzytu.
Źródło:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2023, 14, 2(52); 51--72
2081-5891
Pojawia się w:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Annealing Treatment on (Mg17Al12) Phase Characterization and Corrosion Behavior in Different Solutions for AZ91 Alloy
Autorzy:
Abass, Marwa H.
Abdulkareem, Makarim H.
Hussein, Hussien A.
Powiązania:
https://bibliotekanauki.pl/articles/2201907.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
AZ91
alloy
heat treatment
corrosion
microstructure
antibacterial
hardness
Opis:
Heat treatment is the most suitable technique for altering the microstructure and, consequently, it is possible to create the optimal balance of corrosion resistance and mechanical strength in a material by carefully regulating the conditions during the heating process. The present work aims to investigate the effect of heat treatments (annealing) at (300°C) at different times (10, 20, and 30 hr) on the magnesium alloy. How the Mg17Al12 phase influences the corrosion behavior of AZ91D magnesium alloy was quantified in different solution (SBF, Lactic and Ringer). It was able to construct an extensive range of Mg17Al12 phase volume fractions by varying the annealing period. The corrosion potential of many specimens with varied proportions of the Mg17Al12 phase was evaluated. The results of the conducted tests manifested that the material's resistance to corrosion greatly improved with an increase in the volume fraction of Mg17Al12 phase. The effect of heat treatment on the microstructure was analyzed using transmission electron microscopy and X-ray diffraction. The SEM photographs evinced that the amount of β-Mg17Al12 phase decreased significantly, with the distribution occurring at the grain boundaries and with increasing the time of annealing, resulting in a highly saturated α-grain. The XRD validated the all material peaks of phases that are present. The corrosion test behavior of AZ91 alloy in the simulated body fluid (SBF), lactic, and Ringer solutions was investigated through electrochemical measurements, the result was elucidated as measured along the Tafel slope, and the corrosion current density of all heat treated samples was lower than that of the as-cast sample. The measurement of hardness (HV) demonstrated that the hardness decreased to (64.5 HV0.5) during the heat treatment. The result antibacterial efficiency was revealed that AZ91 at 30 hr was best then as cast against the bacteria E.coli.
Źródło:
Advances in Science and Technology. Research Journal; 2023, 17, 2; 330--341
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Boron Accompanied by Chromium, Vanadium and Titanium on the Transformation Temperatures of Low-Alloy Cast Steels
Autorzy:
Białobrzeska, Beata
Dziurka, Rafał
Powiązania:
https://bibliotekanauki.pl/articles/2203729.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
boron
cast steels
dilatometric research
microstructure
Opis:
The purpose of the research was to examine the influence of boron on the selected properties of low-alloy cast steels. The chemical compositions of the cast steels were designed especially for this study to contain different alloy elements. The first composition lacked significant alloying elements. The subsequent grades of cast steels had the addition of chrome, chrome with vanadium, and chrome with titanium. It was decided to investigate the influence of boron in the presence of such alloying additives on the temperature of phase transformations. On the basis of dilatometric curves, the characteristic temperatures of the phase transformations were determined. Additionally, to assess the influence of the cooling rate on the structure of cast steels, an analysis of their microstructure, after full annealing and quenching, was carried out.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 257--267
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Cooling Rates and Intermediate Slab Blank Thickness on the Microstructure and Mechanical Properties of the X70 Pipeline Steel
Autorzy:
Xu, Haijian
Han, Chufei
Yan, Pingyuan
Zhao, Baochun
Li, Weijuan
Powiązania:
https://bibliotekanauki.pl/articles/28099617.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
cooling rate
microstructure
pipe steel
acicular ferrite
low-alloy
Opis:
In this study, the microstructures and mechanical properties of X70 pipeline steels produced with varying Mo contents, accelerated cooling rate and intermediate slab blank thickness are systematically investigated. Results showed that the microstructures and mechanical properties of the X70 pipeline steels were strongly affected by Mo addition. The pearlite and proeutectoid ferrite formation is obviously inhibited in containing-Mo steel and the acicular ferrite (AF) is obtained in a wide range of cooling rates. With the increasing the cooling rates, the AF constituent amount increases. The grains can be refined by increasing the thickness of intermediate slab for enhancing the cumulative reduction rates, and meanwhile increase the number density of precipitates. It was proved by simulation and industrial trials that the low-alloy X70 pipeline steels can be produced increasing cooling rates and the thickness of intermediate slab without strength and toughness degradation which also reduce alloy cost.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 649--658
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Microstructure and Mechanical Properties of Al 3003 Alloy Weld by Stationary Shoulder Friction Stir Welding Process
Autorzy:
Jung, Woo-Chul
Park, Joo-Heon
Yoon, Sang-Min
Kim, Young Kyun
Powiązania:
https://bibliotekanauki.pl/articles/2203728.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stationary shoulder friction stir welding
aluminum 3003 alloy
microstructure
mechanical properties
Opis:
The lap joint welding of Al 3003 alloy by stationary shoulder friction stir welding (SSFSW) was performed under the conditions of tool rotation and welding speed, and it was confirmed that the welding was performed under all conditions. The tunnel defects and pores were formed in the weld zone at the lowest tool rotation and welding speed, and it is increased, the weld surface has been improved. At the same tool rotation speed at the welding speed is increased, the grain size was refined in the stir zone (SZ) and thus the hardness increased by about 14% compared to the base metal. The tensile shear strength is measured to be 10 kN or more under most conditions, and in the 4000 rpm with high heat input, the shear tensile strength was measured relatively lower than other conditions due to excessive heat input of the material.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 113--118
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of spray distance on the microstructure and corrosion resistance of WC - based coatings sprayed by HVOF
Autorzy:
Jonda, Ewa
Łatka, Leszek
Maciej, Artur
Godzierz, Marcin
Gołombek, Klaudiusz
Radziszewski, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2204526.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
WC-based powders
AZ31 magnesium alloy
high velocity oxy fuel
HVOF
microstructure
corrosion resistance
stop magnezu AZ31
mikrostruktura
odporność na korozję
natryskiwanie naddźwiękowe cieplne
proszek na bazie węglika wolframu
Opis:
Cermet coatings provide protection against aggressive operating environment of machine and device elements, such as corrosion, wear or high-temperature conditions. Currently WC-based cermet coatings are frequently used in the different industry branches. In this work, conventional WC-based powders (WC-Co and WC-Co-Cr) were sprayed with High Velocity Oxy Fuel (HVOF) onto AZ31 magnesium alloy with different spray distances (320 and 400 mm). The aim of the research was to investigate the effect of the spray distance on the microstructure of the coatings, phase composition and electrochemical corrosion resistance. Results revealed that higher spray distance results in greater porosity, 1.9% and 2.3% for 320 mm and 2.8% and 3.1% for 400 mm in case of WC-Co and WC-Co-Cr coatings, respectively. Also the influence has been observed for coatings microhardness, c.a. 1300 HV0.3 for shorter spray distance, whereas for longer one it was less than 1100 HV0.3. The corrosion resistance estimated in potentiodynamic polarization measurements was the best for WC-Co-Cr coating deposited from the shorter spray distance, corrosion current density was equal to 2.9 µA·cm-2 and polarization resistance was equal to 8424 Ω∙cm2.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 2; art. no. e144610
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the Heating Temperature of a Nickel-Chromium Steel Charge Material on the Stability of the Forging Process and the Durability of the Die
Autorzy:
Hawryluk, Marek R.
Lachowicz, Marzena
Janik, Marta
Gronostajski, Zbigniew
Stachowicz, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/28099626.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
forging
engine
chromium-nickel steel with austenitic microstructure
valve
forging tools
Opis:
The study discusses the issues of low durability of dies used in the first operation of producing a valve type forging from high nickel steel assigned for the application in motor truck engines. The analyzed process of manufacturing the exhaust valve forgings is realized in the coextrusion technology, followed by forging in closed dies. This process is difficult to master, mainly due to elevated adhesion of the charge material (high nickel steel - NCF3015) to the tool substrate as well as very high abrasive wear of the tool, most probably caused by the dissolution of hard carbide precipitates during the charge heating. A big temperature scatter of the charge during the heating and its short presence in the inductor prevents microstructure homogenization of the bearing roller and dissolution of hard precipitates. In effect, this causes an increase of the forging force and the pressures in the contact, which, in extreme cases, is the cause of the blocking of the forging already at the beginning of the process. In order to analyze this issue, complex investigations were conducted, which included: numerical modelling, dilatometric tests and hardness measurements. The microstructure examinations after the heating process pointed to lack of structure repeatability; the dilatometric tests determined the phase transformations, and the FEM results enabled an analysis of the process for different charge hardness values. On the basis of the conducted analyzes, it was found that the batch material heating process was not repeatable, because the collected samples showed a different amount of dissolved carbides in the microstructure, which translated into different hardnesses (from over 300 HV to 192 HV). Also, the results of numerical modeling showed that lower charge temperature translates into greater forces (by about 100 kN) and normal stresses (1000 MPa for the nominal process and 1500 MPa for a harder charge) and equivalent stresses in the tools (respectively: 1300 MPa and over 1800 MPa), as well as abrasive wear (3000 MPa mm; 4500 MPa mm). The obtained results determined the directions of further studies aiming at improvement of the production process and thus increase of tool durability.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 711--722
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 1094

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