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Tytuł:
On the Load Dependence of Micro-Hardness Measurements: Analysis of Data by Different Models and Evaluation of Measurement Errors
Autorzy:
Petrik, J.
Powiązania:
https://bibliotekanauki.pl/articles/353270.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
micro-hardness
ISE
standard reference block
Opis:
The influence of applied loads between 0.09807 N and 0.9807 N on measured values of micro-hardness was evaluated by Meyer’s index n, proportional specimen resistance model (PSR) and Hays – Kendall methods, Total Dispersion Zone and Analysis of Variance (ANOVA). The measurement was repeated 6 times using the same hardness reference block with standard hardness Hc = 327 HV0.05 as a sample. The influence of the load on the measured value of micro-hardness is statistically significant, and the relationship between applied load and micro-hardness manifests reverse indentation size effect (ISE) for most of “measurements”. The high value of the uncertainty of results can affect the existence and nature of ISE, especially at low loads.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 4; 1819-1824
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
“In-vitro” Tests on New Biodegradable Metallic Material Based on ZnMgY
Autorzy:
Panaghie, Catalin
Cimpoesu, Nicanor
Benchea, Marcelin
Roman, Ana-Maria
Manole, Vasile
Alexandru, Adrian
Cimpoesu, Ramona
Cazacu, Marius Mihai
Wnuk, Izabela
Zegan, Georgeta
Powiązania:
https://bibliotekanauki.pl/articles/2106563.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biodegradable
tafel
potentiostat
micro-hardness
10xDPBS
Opis:
Biodegradable materials represent a new class of biocompatible materials with applications in many medical cases where the support must be provided only for a certain period. In this article obtaining of ZnMgY alloy is presented along with some basic characteristic investigations like chemical composition (energy dispersive spectroscopy - EDS), microstructure (optical microscopy - OM and scanning and electron microscopy - SEM), immersion behavior in 10xDPBS (Dulbecco Phosphate Buffer Saline) solution (mass loss and surface degradation), electro-corrosion behavior (potentiostat with a three electrodes cell) and micro-hardness of the experimental alloy compared to cast Zn and ZnMg materials. The results present an improvement of micro-hardness of Zn by alloying with Mg and Y and a modification of corrosion resistance.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 587--594
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Different Torsion Pitch on Microstructural Evolution and Strengthening Mechanism of Al Wires
Autorzy:
Sedighi, M.
Vaezi, A.
Pourbashiri, M.
Powiązania:
https://bibliotekanauki.pl/articles/351811.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
torsion deformation
tensile test
micro hardness
microstructure
Al wire
Opis:
This paper focused on the effect of pure torsion deformation and various torsion pitches on the mechanical properties of the commercial pure Al wires which has not been examined so far. The initial wires with diameter of 4 mm have been torsion deformed to different pitch length (PL). In order to investigate the effect of gradient microstructure caused by torsion deformation, three different pitch length of 15 mm, 20 mm and 30 mm are considered. The results revealed that the level of grain refinement is correlated with the amount of induced plastic shear strain by torsion deformation. For the wire with pitch length of 15 mm, the grain sizes decreased to about 106 μm and 47 μm in the wire center and edge from the initial size of about 150 μm of the annealed wire. The micro-hardness measurement results show a gradient distribution of hardness from the wire center to the wire surface that confirmed the increasing trend of plastic shear strain obtained by FE simulations. The hardness of annealed sample (35 HV) is increased up to 73 HV at the wire surface for the smallest pitch length. The yield and ultimate tensile strength of the torsion deformed wires are also increased up to about 85 MPa and 152 MPa from the initial values of 38 MPa and 103 MPa of the annealed one respectively while the maximum elongation reduced significantly.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 625-632
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Friction and Wear Behavior of Direct Metal Deposition on SUH3
Autorzy:
Choi, Byungjoo
Cho, In-Sik
Jung, Do-Hyun
Lee, Moon G.
Jeon, Yongho
Powiązania:
https://bibliotekanauki.pl/articles/352111.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
direct metal deposition
heat pretreatment
friction test
wear test
micro-hardness
Opis:
Poppet valves made from high-frequency heat-treated SUH3 steel have insufficient durability, and scratches appear on the valve face in prolonged use. It is necessary to develop surface treatment technology with excellent durability to prevent the deterioration of engine performance. Therefore, a surface treatment technology with higher abrasion resistance than existing processes was developed by direct metal deposition to the face where the cylinder and valve are closed. In this study, heat pretreatment and deposition tests were performed on three materials to find suitable powders. In the performance evaluation, the hardness, friction coefficient, and wear rate were measured. Direct metal deposition using Inconel 738 and Stellite 6 powders without heat pretreatment were experimentally verified to have excellent durability.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 841-844
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructural Characteristics of Ti-Al-Dy Alloy Produced by High Energy Ball Milling
Autorzy:
Kim, Yuri
Rhee, Hoseong
Chang, Si Young
Powiązania:
https://bibliotekanauki.pl/articles/2049319.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high energy ball milling
Ti-Al-Dy powders
SPS
microstructure
micro-hardness
Opis:
In this study, the alloying of Ti, Al and Dy powders by high energy ball milling, and the spark plasma sintering (SPS) characteristics of as milled powders have been investigated based on the observation of microstructure. Pure Ti, 6wt% Al and 4wt% Dy powders were mixed and milled with zirconia balls at 600 ~ 1000 rpm for 3h in an Ar gas. The initial sizes of Ti, Al and Dy powders were approximately 20, 40, and 200 μm, respectively. With increasing the milling speed from 600 to 1000 rpm, the size of mixing powders reduced from 120 to 15 μm. On the other hand, from XRD results of powders milled at higher speeds than 700rpm, the peaks of Ti3Al and AlDy phases were identified, indicating the successful alloying. Therefore, the powders milled at 800 rpm have been employed for the SPS under the applied pressure of 50 MPa at 1373K for 15 min. In the SPSed sample, the Al3Dy and two ternary Ti-Al-Dy phases were newly detected, while the peak of AlDy phase disappeared. The SPSed Ti-6Al-4Dy alloy revealed high relative density and micro-hardness of approximately 99% and 950Hv, respectively.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 3; 789-783
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of Process Parameters of Ultrasonic Welding on Dissimilar Metal Joints
Autorzy:
Mohan Kumar, Anand
Rajasekar, R.
Karthik, Vaduganathan
Kheawhom, Soorathep
Powiązania:
https://bibliotekanauki.pl/articles/2049410.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
3105-H18 aluminium alloy
pure copper
ultrasonic welding
optimization
micro-hardness
Opis:
Nowadays the automotive industry mostly prefers innovative solid-state welding technologies that would enable to welding of lightweight and high-performance materials. In this work, 3105-H18 Aluminium alloy (Al) and pure Copper (Cu) specimens with 0.5 mm thickness have been ultrasonically welded in a dissimilar (Al-Cu) manner. Optimization of process parameters of ultra-sonic welding has been carried out through full factorial method, three levels of variables considered for this experimental studies namely, weld pressure, amplitude, and time, also each variable interaction with welding strength has been studied. Additionally, micro-hardness and microstructure investigation in welded joints has been studied. The result shows that the weld strength greatly influenced weld amplitude at a medium and higher level of weld pressure. The interface micro-hardness of the welded joint has lower compared to the base metal.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 3; 887-892
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Forge Application on Microstructural and Mechanical Properties of AISI 316 Using Direct Drive Friction Welding Process
Autorzy:
Hassan, Jabbar A.
Boukharouba, T.
Miroud, D.
Powiązania:
https://bibliotekanauki.pl/articles/2125543.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
friction welding
forge phase
micro-hardness
ultimate tensile strength
X-ray diffraction
Opis:
Present study introduces effect of forge application and elimination on microstructural and mechanical properties of AISI 316 during friction welding. Temperature measurements, microstructure, micro-hardness, tensile test, scanning electron microscopy and X-ray diffraction were evaluated. Maximum temperature recorded was 819°C while forge was applied between 357°C-237°C. Thermo-mechanically affected zone and highly plastically deformed zone were created at the interface at elimination and application of forge respectively. Ultimate tensile strength decreased and ductility increased when forge elimination compared to forge application. Tensile fracture was occurred adjacent to the welding interface for both cases, though, after forge application, ductile fracture mode and cleavage features through the fingerprints were observed in the fracture morphology. Redistribution and concentration of gamma iron in 111 level after forge application and heat treated of AISI 316.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 987--992
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Improvement of Surface Properties of SKD61 Powder on S45C Using Laser Cladding
Autorzy:
Kim, Cheol-Woo
Yoo, Hyo-Sang
Powiązania:
https://bibliotekanauki.pl/articles/2174572.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
laser cladding
Micro Vickers hardness
microstructure
polarization curve
Opis:
In this study, we investigated the effect of cladding on structural carbon steel (S45C) using 5%Cr-1.5%Mo-Fe powder (SKD61), which is expected to show economically efficient production of die-casting parts. The process conditions were performed under argon atmosphere using a diode laser source with specialized wavelength of 900-1070 nm, and the output conditions were 3, 4, and 5 kW, respectively. After the cladding was completed, the surface coating layer’s shape and the microstructure were analyzed. The hardness test was carried out with Micro Vickers hardness tester under 500 gram-force along the normal line at the interval of 0.2 mm from the surface to core direction on the cross-sectional area. In addition, polarization curve test of the surface coating layer was performed to investigate the corrosion resistance characteristics.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1465--1468
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric Analysis on the Progression of Mechanical Properties on FSW of Aluminum-Copper Plates
Autorzy:
Deepati, Anil Kumar
Alhazmi, Waleed
Zakri, Waleed
Shaban, Essam
Biswas, Pankaj
Powiązania:
https://bibliotekanauki.pl/articles/2180606.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
tool geometry
process parameters
micro-hardness
tensile strength
weld microstructure
Cu alloy
Al alloy
Opis:
The contemporary work manifests that friction stir welding (FSW) is a viable avenue for joining AA1100 aluminium (Al) to C12200 copper (Cu) plates. In this present study, the response of distinctive welding parameters (viz. tool geometries, tool rotational speed, tool travel speed, and tool plunging depth) on weld quality has been investigated. The present work focused on both microstructural investigation and mechanical properties examination. It has been observed that the process parameters have significant effects on weld quality. The design of the experiments has been executed considering four welding input parameters in two variables and selected L-16 orthogonal array to limit the experimental replications. It has been observed that good quality of welds produced by keeping the tool pin offset around 4mm towards the aluminium side and 2mm towards the copper side. And it has also been noticed that right-hand threaded tool pins are giving good weld quality compared to left-handed thread. The joint efficiencies for the welds E2, E14 which were welded by RHT tools were 75.3% and 74.61% and the Strength (UTS) of the welds for the same tools exhibit’s greater than the LHT tools i.e., 98 and 95Mpa. Moderate hardness values are observed for the same welds E1 and E14 with the parameters 1100rpm, 98welding speed, and 1.6mm tool plunge depth. . It also noticed that the weld quality can be significantly enhanced by using proper tool plunge and tool pin geometries compared to the other process parameters.
Źródło:
Advances in Science and Technology. Research Journal; 2022, 16, 2; 168--178
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and Mechanical Properties of Explosive Welded Mg/Al Bimetal
Struktura i właściwości mechaniczne połączenia uzyskanego metodą zgrzewania wybuchowego bimetalu Mg/Al
Autorzy:
Balga, D.
Ostroushko, D.
Saksl, K.
Mazancová, E.
Milković, O.
Powiązania:
https://bibliotekanauki.pl/articles/354953.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
explosive welding
Mg/Al bimetal
micro-hardness
micro-diffraction
PETRA III
zgrzewanie wybuchowe
bimetal Mg/Al
mikrotwardość
mikrodyfrakcja
Opis:
In the article we analyzed shape, local mechanical properties, chemical and phase composition of Magnesium/Aluminium cladded material prepared by explosion welding. In particular we focus our investigation on Mg/Al interface and areas close to the joint. Hardness of the joined materials measured far from their interface is similar for both materials, however in the region of interface the hardness drops down by 40%. Phase transformations in the interface was examined by a hard X-ray micro-diffraction experiment performed at beamline P07 at PETRA III at the energy of 99 keV which helped us identify in Al: fcc-Al, Al2 Cu tetragonal and Al7 Cu2 Fe tetragonal and in Mg: hcp-Mg, Mg2 Si cubic phases. In the interface we haven’t observed any new intermetallics, but computation of lattice parameters and profiles of Al and Mg peaks proved an existence of solid solution with different gradient of chemical composition.
W pracy analizowano kształt, lokalne właściwości mechaniczne, chemiczne oraz składników fazowych Mg/Al materiałów platerowanych otrzymanych metodą zgrzewania wybuchowego. W szczególności, skupiono się na badaniach połączenia fazy Mg/Al oraz obszarów znajdujących się w pobliżu połączenia. Twardość połączonych materiałów badano w znacznej odległości od warstwy samego połączenia, i zauważono, iż jest ona podobna do twardości materiałów wyjściowych, jednakże twardość w regionie warstwy połączenia spada o 40%. Przemiana fazowa w warstwie połączenia została poddana badaniom mikrodyfrakcyjnym, na urządzeniu P07, PETRA III o energii 99 keV, dzięki której zidentyfikowano w Al fazy tetragonalne: fcc-Al, Al2 Cu oraz Al7 Cu2 Fe i w Mg: heksagonalna Mg oraz kubiczna Mg2 Si. W warstwie połączenia nie zaobserwowano żadnych innych nowych faz międzymetalicznych. Obliczone parametry sieci komórki elementarnej i profile pików Al i Mg potwierdzają występowanie roztworu stałego z różnym gardientem składu chemicznego.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 4; 1593-1597
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Molybdenum on the Thermal, Structural Properties and Micro Hardness of AlSi10Mg(Cu) Alloy
Autorzy:
Hajduch, P.
Bolibruchova, D.
Djurdjevic, M.
Powiązania:
https://bibliotekanauki.pl/articles/383004.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
alloy AlSiMgCu
influence of molybdenum
thermal analysis
micro hardness
stop AlSiMgCu
wpływ molibdenu
analiza termiczna
mikrotwardość
Opis:
This work is dealing with the impact of molybdenum on the structure properties of commercial cast AlSi10Mg(Cu) alloy. The solidification path of AlSi10Mg(Cu) alloy with various content of molybdenum has been investigated using cooling curve techniques. The samples for testing have been poured into permanent steel mold. The content of molybdenum has been varied from 0 to 0.20 wt. %.The desired chemical composition was achieved by adding of master alloy AlMo10 into commercial AlSi10Mg(Cu) alloy. The micro hardness of as cast alloys with different content of molybdenum has been measured. The microstructure and EDX analysis from the casted samples has been carried out. The results show that molybdenum in commercial AlSi10Cu(Mg) alloy precipitate in the interdendritic region isolated in the form of Al(FeMnMoMg)Si rich intermetallic. The increased content of molybdenum increase slightly liquidus temperature, prolonging precipitation of the last eutectic and surprisingly decrease the micro hardness of commercial alloy for approximately 16 %.
Źródło:
Archives of Foundry Engineering; 2018, 18, 3; 19-24
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of selected properties and surface quality of cured pre-impregnated carbon-fiber fabrics after exposure to sulphuric acid
Autorzy:
Kojnoková, Tatiana
Nový, František
Markovičová, Lenka
Harea, Evgheni
Harea, Evghenii
Powiązania:
https://bibliotekanauki.pl/articles/26081735.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
tkaniny węglowe
żywica epoksydowa
zmiana wagi
jakość powierzchni
carbon fabrics
epoxy resin
micro-hardness
weight change
surface quality
Opis:
This paper deals with changes in selected properties of composite material and surface degradation after exposure to an acidic environment. A carbon fiber-reinforced composite (CFRP) produced from prepregs was tested. The weight change, micro-hardness, and surface degradation of the CFRP composite made of cured pre-impregnated laminates were evaluated in this study. Material consisting of a DT121R epoxy resin matrix with high reactivity and high viscosity, with two reinforcing carbon fabrics layers, is characterized by a low value of tensile strength. Evaluation of changes in the material properties was performed before and after exposure to specific environmental conditions, which are achieved by using a chemical solution of 15% H2SO4 at various temperatures. Subsequently, the effect of 15% H2SO4 at various temperatures on the material properties was monitored. The specimens were immersed in the solution for up to 3 and 6 weeks at the temperatures of 23°C, 40°C, and 60°C. It was found out, that the degradation of the composite material is conditioned by the aging of the epoxy resin (matrix). Carbon fibers (reinforcement) are relatively stable. The weight change, micro-hardness, and surface quality depend on the time of exposure to acidic solution and temperature. The micro-hardness tests show a significant influence on exposure time. The biggest changes in weight change and surface quality of the CFRP composite were observed after exposure at the temperature of 60°C.
Źródło:
Production Engineering Archives; 2023, 29, 1; 1--6
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the Influence of Vibratory Machining on Titanium Alloys Properties
Autorzy:
Bańkowski, D.
Spadło, S.
Powiązania:
https://bibliotekanauki.pl/articles/947596.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
titanium alloy
vibratory machining
finishing treatment
surface roughness
micro-hardness
stop tytanu
obróbka wibracyjna
obróbka wykańczająca
chropowatość powierzchni
mikrotwardość
Opis:
This article proposes these of vibratory machining to Ti-6Al-4V titanium alloy as finishing treatment. Titanium alloy was used in the aerospace industry, military, metallurgical, automotive and medical processes, extreme sports and other. The three-level three-factor Box-Behnken experiment examined the influence of machining time of vibratory machining, the type of mass finishing media used and the initial state of the surface layer on the mass loss, geometric structure of the surface, micro hardness and the optimal process parameters were determined. Considerations were given the surfaces after milling, after cutting with a band saw and after the sanding process. The experiment used three types of mass finishing media: polyester, porcelain and metal. Duration of vibratory machining treatment was assumed to be 20, 40, 60 minutes. The form profiles before and after vibratory machining were determined with the Talysurf CCI Lite - Taylor Hobson optical profiler. Future tests should concern research to carry out tests using abrasive pastes with a larger granulation of abrasive grains, to carry out tests for longer processing times and to determine the time after which the parameters of geometrical structure of the surface change is unnoticeable.
Źródło:
Archives of Foundry Engineering; 2020, 20, 3; 47-52
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of High-Voltage Electromagnetic Pulses on Technological Properties of Diamond Crystals and Kimberlite Rock-Forming Minerals
Wpływ wysokonapięciowych impulsów elektromagnetycznych na właściwości technologiczne kryształów diamentu i minerałów tworzących skały Kimberlite
Autorzy:
Anashkina, N. E.
Bunin, Igor Zh.
Khachatryan, G. K.
Powiązania:
https://bibliotekanauki.pl/articles/318108.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
kimberlit
diamenty
impulsy nanosekundowe wysokiego napięcia
hydrofobowość
mikrotwardość
flotowalność
kimberlite
diamonds
high-voltage nanosecond pulses
hydrophobicity
micro-hardness
floatability
Opis:
For optimization of diamond processing technology the influence of nanosecond high voltage pulses on mechanical and technological properties of diamond crystals and kimberlite rock-forming minerals (calcite, olivine, serpentine) was investigated. Using methods of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), microscopy and mikrohardness measurement the changes of structural, physic-chemical surface properties, and microhardness of minerals as the result of impacts, was studied. Non-thermal impacts caused a decrease of kimberlite rock-forming minerals microhardness in general to 40–66% as the result of surface microstructure destruction which is caused by formation of micro cracks, traces of surface breakdown and other defects. At the same time, the pulse energy impact on natural diamonds led to formation of B2 type crystal lattice microsift defects, elevated concentration of which increases the hardness properties of crystals. The obtained result indicates possibility of applying pulsed energy effects to improve the softening efficiency of diamond-bearing kimberlites rock-forming minerals without damaging the diamond crystals and ensuring their preservation by the subsequent grinding of ores. The effect of increasing the natural diamonds flotation activity by 14% (from 47% to 61%) was experimentally established as a result of processing diamond crystals with nanosecond pulses (~ 10–50 sec), which indicates the principal possibility of using pulsed energy impacts to intensify the diamond flotation during processing diamond-bearing kimberlites.
W celu optymalizacji technologii przeróbki diamentów zbadano wpływ impulsów wysokiego napięcia nanosekundowego na właściwości mechaniczne i technologiczne kryształów diamentu i minerałów tworzących skały kimberlitowe (kalcyt, oliwin, serpentynit). Przy pomocy metod spektroskopii w podczerwieni z transformacją Fouriera (FTIR), rentgenowskiej spektroskopii fotoelektronowej (XPS), mikroskopii i pomiaru mikrotwardości badano zmiany strukturalnych, fizykochemicznych właściwości powierzchni oraz mikrotwardości minerałów w wyniku uderzeń. Uderzenia nietermiczne spowodowały zmniejszenie mikrotwardości minerałów tworzących skały kimberlitowe ogólnie do 40–66% w wyniku zniszczenia mikrostruktury powierzchni, spowodowanego powstawaniem mikropęknięć, śladów rozpadu powierzchni i innych wad. Jednocześnie wpływ energii impulsu na naturalne diamenty doprowadził do powstania defektów mikroprzesunięcia sieci krystalicznej typu B2, których podwyższone stężenie zwiększa właściwości twardości kryształów. Uzyskany wynik wskazuje na możliwość zastosowania efektów pulsacji energii w celu poprawy wydajności zmiękczania zawierających diamenty minerałów tworzących skały jak kimberlity, bez uszkadzania kryształów diamentu i zapewnienia ich zachowania w czasie późniejszego mielenia rudy. Efekt zwiększenia naturalnej aktywności flotacyjnej diamentów o 14% (z 47 do 61%) ustalono eksperymentalnie w wyniku przetwarzania kryształów diamentu za pomocą impulsów nanosekundowych (~ 10–50 sekund), co wskazuje na główną możliwość wykorzystania energii pulsacyjnej. Impulsy wpływają na intensyfikację flotacji diamentów podczas przetwarzania kimberlitów zawierających diamenty.
Źródło:
Inżynieria Mineralna; 2019, 21, 1/2; 133-138
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hardness investigation of conventional, bulk fill and flowable dental composites
Autorzy:
Georgiev, G.
Dikova, T.
Powiązania:
https://bibliotekanauki.pl/articles/2055754.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
resin-based composites
micro-hardness
light intensity
irradiation time
layer thickness
kompozyty żywiczne
mikrotwardość
natężenie oświetlenia
czas nasłonecznienia
grubość warstwy
Opis:
Purpose: of the present paper is to investigate the micro-hardness of three types of resin-based composites – conventional, bulk fill and flowable. Design/methodology/approach: Cylindrical specimens with a diameter of 5 mm and thicknesses of 2, 3 and 4 mm were made from each composite. They were light cured for 20, 40 and 60 s with light intensity of 600, 1000 or 1500 mW/cm2. The Vickers micro-hardness was measured on the top and bottom surface of the specimens. Findings: The highest micro-hardness was measured in bulk fill composite, followed by conventional and the lowest was measured in the flowable one. Increasing the light intensity leads to increase of the micro-hardness on both surfaces of the three composites. The increase of the irradiation time results in increase of the micro-hardness mainly on the bottom surface of the composites. The change of the layer thickness influences the conventional and the flowable composites and almost does not affect the hardness of the bulk fill composite. Research limitations/implications: The limitations of this study concerns to the values of the light intensity, which are defined by the light curing unit (LCU) used. There are many LCUs on the market; consequently, constant investigations of dental composites micro-hardness are needed. Practical implications: The investigation of the micro-hardness of the three types of composites in different modes would be very helpful for clinicians to obtain successful polymerization of composite restorations in their everyday practice. Originality/value: The micro-hardness of three types resin-based dental composites – conventional, bulk fill and flowable is investigated and compared in varying of three mode parameters – light intensity, curing time and layer thickness.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2021, 109, 2; 68--77
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 18

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