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1

Evaluation of selected properties and surface quality of cured pre-impregnated carbon-fiber fabrics after exposure to sulphuric acid

Kojnoková Tatiana, Nový František, Markovičová Lenka, Harea Evgheni, Harea Evghenii

Production Engineering Archives

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2023

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Vol. 29, Iss. 1

1--6

EN

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.

2

Microstructure and Mechanical Properties of Stainless Steel/Aluminum Multilayer Composites by One-Step Explosive Welding

Hu Xiaoyan, Liu Yingbin, Yang Li, Huang Xiaochen

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

939--946

EN

The stainless steel/aluminum multilayer composites were prepared by one-step explosive welding using ammonium nitrate explosive with two different thicknesses. The microstructure and mechanical properties of the multilayer composites were examined. There is a thin metallurgical melting zone at each bonding interface, consisting mostly of iron and aluminum elements. However, the micro-crack appears in the second metallurgical bonding zone obtained using the explosive of 24 mm thickness. The microhardness values at the four bonding interfaces are higher than those of bulk 1060 aluminum and 304 stainless steel. The yield strength of the multilayer composites obtained in the two cases is higher than that of the original 304 stainless steel while the tensile strength is between those of the original 1060 aluminum and 304 stainless steel. Meanwhile, the tensile strength and yield strength of multilayer composites obtained by explosive welding with explosive of 20 mm thickness are relatively higher.

3

Microstructure and Mechanical Properties of Stainless Steel/Aluminum Multilayer Composites by One-Step Explosive Welding

Hu Xiaoyan, Liu Yingbing, Yang Li, Huang Xiaochen

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

1211--1217

EN

The stainless steel/aluminum multilayer composites were prepared by one-step explosive welding using ammonium nitrate explosive with two different thicknesses. The microstructure and mechanical properties of the multilayer composites were examined. There is a thin metallurgical melting zone at each bonding interface, consisting mostly of iron and aluminum elements. However, the micro-crack appears in the second metallurgical bonding zone obtained using the explosive of 24 mm thickness. The micro-hardness values at the four bonding interfaces are higher than those of bulk 1060 aluminum and 304 stainless steel. The yield strength of the multilayer composites obtained in the two cases is higher than that of the original 304 stainless steel while the tensile strength is between those of the original 1060 aluminum and 304 stainless steel. Meanwhile, the tensile strength and yield strength of multilayer composites obtained by explosive welding with explosive of 20 mm thickness are relatively higher.

4

“In-vitro” Tests on New Biodegradable Metallic Material Based on ZnMgY

Panaghie Catalin, Cimpoesu Nicanor, Benchea Marcelin, Roman Ana-Maria, Manole Vasile, Alexandru Adrian, Cimpoesu Ramona, Cazacu Marius Mihai, Wnuk Izabela, Zegan Georgeta

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

587--594

EN

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.

5

Effect of Forge Application on Microstructural and Mechanical Properties of AISI 316 Using Direct Drive Friction Welding Process

Hassan Jabbar A., Boukharouba T., Miroud D.

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

987--992

EN

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.

6

Parametric Analysis on the Progression of Mechanical Properties on FSW of Aluminum-Copper Plates

Deepati Anil Kumar, Alhazmi Waleed, Zakri Waleed, Shaban Essam, Biswas Pankaj

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 2

168--178

EN

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.

7

Hardness investigation of conventional, bulk fill and flowable dental composites

Georgiev G., Dikova T.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

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Vol. 109, nr 2

68--77

EN

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.

8

Optimization of Process Parameters of Ultrasonic Welding on Dissimilar Metal Joints

Mohan Kumar Anand, Rajasekar R., Karthik Vaduganathan, Kheawhom Soorathep

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

887--892

EN

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.

9

Microstructural Characteristics of Ti-Al-Dy Alloy Produced by High Energy Ball Milling

Kim Yuri, Rhee Hoseong, Chang Si Young

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

789--783

EN

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.

10

Research on the Influence of Vibratory Machining on Titanium Alloys Properties

Bańkowski D., Spadło S.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

47--52

EN

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.

11

Influence of High-Voltage Electromagnetic Pulses on Technological Properties of Diamond Crystals and Kimberlite Rock-Forming Minerals

Anashkina N. E., Bunin Igor Zh., Khachatryan G. K.

Inżynieria Mineralna

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2019

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R. 21, nr 1/2

133--138

EN

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.

PL

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.

12

Friction and Wear Behavior of Direct Metal Deposition on SUH3

Choi Byungjoo, Cho In-Sik, Jung Do-Hyun, Lee Moon G., Jeon Yongho

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

841--844

EN

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.

13

On wire spark erosion machining induced surface integrity of Ni55.8Ti shape memory alloys

Sharma Neeraj, Gupta Kapil, Davim Joao Paulo

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 3

680--693

EN

Ni55.8Ti shape memory alloys (SMAs) find applications in different fields of medical and engineering. In every field, surface integrity greatly affects the functional performance of shape memory alloy parts. In the present work, wire spark erosion machining of Ni55.8Ti shape memory alloys has been conducted and surface integrity parameters of the machined specimens have been evaluated. Experiments are designed using Taguchi L16 robust design of experiment technique. Effect of important process parameters, i.e. voltage, pulse-on time and pulse-off time on maximum surface roughness has been studied. Deterioration in surface integrity at various combinations of pulse-on and pulse-of time which produced high discharge energy has been observed. Scanned electron microscopic investigation, energy dispersive spectroscopy and XRD analyses, roughness measurement, and micro-hardness testing results are presented, analyzed and discussed. Optimization of process parameters resulted in surface integrity enhancement with low roughness (Rt – 7.78 mm and Ra – 1.45 mm) and very thin recast layer (4–6 mm) along with minimum subsurface defects.

14

On the Load Dependence of Micro-Hardness Measurements: Analysis of Data by Different Models and Evaluation of Measurement Errors

Petrik J.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

1819--1824

EN

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.

15

Investigations on effect of process parameters of electrodeposited Ni-Al2O3 composite coating using orthogonal array approach and mathematical modeling

Jeyaraj S., Arulshri K. P., Sivasankaran S.

Archives of Civil and Mechanical Engineering

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2016

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Vol. 16, no. 1

168--177

EN

This research article aims at preparation of nickel-aluminum oxide (Ni-Al2O3) metal matrix composite coatings that were prepared from conventional electro-deposition process. Micron sized alumina particles were deposited in nickel matrix by electro-co-deposition technique. The primary electroplating parameters of current density, pH value of electrolyte, temperature of bath, amount of ceramic particles (Al2O3) in bath, and agitation speed were considered for experimental studies. Experimental design and run orders were framed by orthogonal array of Taguchi's approach. L27 orthogonal array was chosen for experimental design based on five plating parameters and three levels. The experiments were conducted by adjusting the plating parameters and the samples were prepared from electrolytic bath. Volume fraction of Al2O3 and micro-hardness of deposits were recorded for each coated sample systematically. The mean effect studies of electroplating parameters were investigated using Taguchi's approach. The S/N ratio values for the response of micro-hardness were calculated and analyzed for significances of independent input parameters. It was found that current density, pH, temperature and agitation speed were the most significant factors. A second order quadratic equation was developed as prediction model for micro-hardness. The predicted micro-hardness values were found to be in good agreement with the experimental results.

16

Structure and Mechanical Properties of Explosive Welded Mg/Al Bimetal

Balga D., Ostroushko D., Saksl K., Mazancová E., Milković O.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 4

1593--1597

EN

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.

PL

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.

17

Productivity and reliability improvement in turning Inconel 718 alloy : case study

Zębala W., Słodki B., Struzikiewicz G.

Eksploatacja i Niezawodność

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2013

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Vol. 15, no. 4

421--426

EN

The paper presents an investigation of Inconel 718 alloy finishing turning, using a procedure that allows the optimal cutting data to be found with a maximization of the metal removal rate as the optimization criterion. The optimization procedure does not allow the required values of the chosen surface roughness indicator, cutting force and cutting tool wedge temperature to be exceeded at the same time. The optimization procedure includes the preliminary cutting tests for establishing the range of cutting data (feed and depth of cut) for the correct chip breaking as well as research concerning micro-hardness measurements which enables the cold work zone to be determined and the minimal value of the feed to be defined. The functionality of the algorithm was verified by using the improvement in machining productivity and reliability of an aircraft engine element as an example.

PL

Artykuł opisuje badania obróbki wykończeniowej toczeniem stopu Inconel 718, mające na celu optymalizację parametrów skrawania z uwzględnieniem maksymalizacji objętościowej wydajności obróbki, jako kryterium optymalizacyjnego. Proponowana procedura uwzględnia wymagane w procesie ograniczenia dotyczące wartości parametru chropowatości obrabianej powierzchni, siły skrawania oraz maksymalnej temperatury w strefie skrawania. Procedura optymalizacyjna zawiera wstępne testy mające na celu ustalenie w lokalnych warunkach obróbki użytecznego zakresu parametrów skrawania (posuwu i głębokości skrawania) dla otrzymania korzystnej postaci wiórów. Wykonane pomiary mikrotwardości w strefie skrawania umożliwiły określenie wielkości strefy zgniotu warstwy wierzchniej, co z kolei pozwoliło na zdefiniowanie minimalnej wartości posuwu. Procedurę optymalizacyjną zweryfikowano na przykładzie obróbki wybranej powierzchni elementu silnika lotniczego. Osiągnięto znaczną poprawę produktywności i niezawodności procesu obróbki.

18

Influence of Laser Alloying with Amorphous Boron on Structure and Microhardness of 41Cr4

Wiśniewski K., Pertek A.

Archives of Metallurgy and Materials

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2009

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Vol. 54, iss. 1

111-114

EN

Influence of laser alloying on structure, and microhardness of surface layers was investigated. Alloying depended on laser re-melting of 41Cr4 steel's surface layer with coated paste containing amorphous boron. In order to produce those layers, the technological laser TRUMPF TLF 2600 Turbo CO2 of the nominal power 2.6 kW was applied. Boriding was carried out with laser power P=0.91 kW, P=1.3 kW and with laser beam scanning rate v in ranging from 0.17 m/min to 5.76 m/min, and with beam diameter 2 mm. Influence of laser treatment parameters on thickness of melted zone as well as microstructure of surface layer was tested. Microhardness was tested along the axis of melted zone, perpendicular to scanned surface. In order to measure microhardness Vickers’ method with tester Zwick 3212 B was applied. On the base of microhardness profile analysis, the dependence of the average hardness in melted zone on laser beam scanning rate was determined. With increasing scanning speed average microhardness in remelted zone increase from 600 HV to 1600 HV. To observe microstructure optical microscope Metaval as well as scanning electron microscope Tescan VEGA 5135 were applied. Tests proved diversified structure of surface layer, depending on laser treatment parameters. Structure had an eutectic character with large refinement when a higher scanning speed was used. Thickness of melted zone with used parameters could obtain from 77 μm to 795 μm was obtained. Results were compared with those prepared by laser re-melting of diffusion borided layer. It was found that both structures and microhardness was similar.

PL

W pracy zbadano wpływ stopowania laserowego na strukturę i mikrotwardość warstwy wierzchniej. Stopowanie polegało na przetapianiu laserem warstwy wierzchniej stali 41Cr4 pokrytej pastą zawierajacą amorficzny bor. Do wytwarzania warstw został zastosowany laser technologiczny TRUMPF TLF 2600 Turbo CO2 o mocy nominalnej 2,6 kW. Borowanie zostało przeprowadzone przy mocy lasera P=0,91 kW i P=1,3 kW oraz przy szybkościach skanowania wiązką w zakresie 0,17 m/min do 5,76 m/min, przy średnicy wiązki 2 mm. Zbadano wpływ parametrów obróbki laserowej na głębokość strefy przetopionej i mikrostrukturę warstwy wierzchniej. Mikrotwardość została zbadania wzdłuż osi strefy przetopionej prostopadle do skanowanej powierzchni. Mikrotwardość badano metodą Vickers'a przy użyciu twardościomierza Zwick 3212B. Na podstawie analizy profili mikrotwardości została wyznaczona zależność średniej mikrotwardości w strefie przetopionej od szybkości skanowania wiązką lasera. Ze wzrostem szybkości skanowania średnia mikrotwardość w strefie przetopionej wzrasta z 600 HV do 1600 HV. Do obserwacji mikrostruktury został użyty mikroskop Metaval, jak również Tescan VEGA 5135. Badania wykazały zróżnicowaną strukturę warstwy wierzchniej zależną od parametrów obróbki laserowej. Struktura ma charakter eutektyki z dużym rozdrobnieniem, gdy została użyta wyższa szybkość skanowania. Grubość strefy przetopionej uzyskana przy stosowanych parametrach wynosi 77 μm do 795 μm. Wyniki zostały porównane z wynikami badań dyfuzyjnych warstw borowanych przetapianych laserowo. Wykazano, że struktury i mikrotwardości są podobne.

19

Badania struktury i mikrotwardości warstwy konstutuowanej laserowo na stali konstrukcyjnej

Kłysz S., Bień A.

Prace Naukowe Instytutu Technicznego Wojsk Lotniczych

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2008

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nr 23

37-49

PL

W pracy przedstawiono wyniki badań makro- i mikroskopowych struktury i pomiarów mikro-twardości warstwy wierzchniej próbek ze stali do ulepszania cieplnego 50H, poddanej laserowemu utwardzaniu. Na podstawie badań rentgenowskich przeprowadzonych na dyfraktometrach DRON-4 i Seifert XRD 3003 określono parametry sieci krystalograficznej i ilościową zawartość poszczególnych faz.

EN

The paper has been intended to present results of the micro- and macroscopic examina-tion of the structure, as well as measurements of micro-hardness of surface layers of specimens made from the toughening (heat-treatable) constructional steel 50H subjected to laser hardening. Basing on X-ray examination with the DRON-4 and the Seifert XRD 3003 diffractometers, parameters of crystalline lattice and quantitative contents of particu-lar phases have been found.

20

The diffusive barriers in copper with austenitic steel joint brazed with Cu-P-Ag filier metal

Mirski Z., Granat K., Prasałek A.

Archives of Metallurgy and Materials

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2008

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Vol. 53, iss. 4

1035-1046

EN

This work presents problems resulting from brazing of copper with austenitic steel type 18/9 (18/10). Both metals show considerable differences in physical-chemical and mechanical properties, which demonstrate essential influence on the properties of brazed joints, particularly with the use of filier metals based on Cu-P (+Ag). Brazed joints of copper with austenitic steel with the use of L-Agl5P (CP 102 according to PN-EN 1044) silver filier metal with phosphorus have been madę. Brazing of different kinds of steel as well as nickel and its alloys with this filier metal is forbidden because of creation on fragile reactionary phases at the boundary of brazed joint on steel side (nickel). However, considering cases of application of this group of filier metals on Cu-P (+Ag, Sn) matrix for steel brazing, a diffusive barrier on Cr-Ni (18/10) steel surface should be created, preventing formation of the fragile intermetallic Fe2P and Ni2P phases. It has been achieved by putting on a galvanized coat of copper of up to 50 µm thickness. Considering the Cu coat adhesion to steel surface, its surface was developed by chemical etching. Basing on surface roughness tests' results, etching parameters have been selected, suitable for correct joint of copper galvanized layer with steel, from the point of view of mechanical adhesion. Research results have been presented basing on microscopic observations with the use of light microscopy, electron microscopy and the analysis of chemical elements with EDX method, micro-hardness measurements as well as static shear test of the obtained brazed joints.

PL

W pracy przedstawiono problemy wynikające z lutowania twardego miedzi ze stalą austenityczną typu 18/9 (18/10). Obydwa metale wykazują znaczne różnice we właściwościach fizykochemicznych i mechanicznych, które mają istotny wpływ na właściwości złączy lutowanych wykonanych szczególnie przy użyciu spoiw na bazie Cu-P (+Ag). Wykonano połączenia lutowane miedzi ze stalą austenityczną z użyciem lutu srebrnego z fosforem gat. L-Agl5P (CP 102 wg PN-EN 1044). Lutowanie tym lutem różnorodnych stali oraz niklu i jego stopów jest zabronione z uwagi na tworzenie się kruchych faz reakcyjnych na granicy połączenia lutowanego od strony stali (niklu). Z uwagi jednak na przypadki stosowania tej grupy lutów na osnowie Cu-P (+Ag, Sn) do lutowania stali należy stworzyć barierę dyfuzyjną na powierzchni stali Cr-Ni (18/10), uniemożliwiającą tworzenie się kruchych faz międzymetalicznych typu Fe2P i Ni2P Zrealizowano to przez nałożenie powłoki galwanicznej z miedzi o grubości dochodzącej do 50 µm. Mając na uwadze przyczepność powłoki Cu do powierzchni stali rozwinięto jej powierzchnię przez trawienie chemiczne. Na podstawie wyników chropowatości powierzchni, wybrano parametry trawienia, właściwe dla poprawnego połączenia warstwy galwanicznej miedzi ze stalą z punktu widzenia adhezji mechanicznej. Wyniki badań przedstawiono na podstawie obserwacji mikroskopowych za pomocą mikroskopii świetlnej, mikroskopii elektronowej i analizy pierwiastków metodą EDX, pomiarów mikrotwardości oraz statycznej próby ścinania wykonanych połączeń lutowanych.