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Number of results: 11
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Analysis of the Thermal and Magnetic Properties of Amorphous Fe61Co10Zr2.5Hf2.5Me2W2B20 (Where Me = Mo, Nb, Ni Or Y) Ribbons

M. Dośpiał K. Gruszka J. Mizera M. Nabiałek M. Szota K. Bloch J. Gondro P. Pietrusiewicz A.V. Sandu A.M. Mustafa Al Bakri S. Walters K. Walters S. Garus
Archives of Metallurgy and Materials | 2016 | No 2 June | DOI: 10.1515/amm-2016-0109
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Authors and Affiliations

M. Dośpiał
K. Gruszka
J. Mizera
M. Nabiałek
M. Szota
K. Bloch
J. Gondro
P. Pietrusiewicz
A.V. Sandu
A.M. Mustafa Al Bakri
S. Walters
K. Walters
S. Garus

Studying the Behavior of the C45 Material when Changing the Tool Geometry Using the Finite Element Method

A.B. Pop A.V. Sandu A. Sachelarie Mihail Aurel Țîțu
Archives of Metallurgy and Materials | 2022 | vol. 67 | No 2 | 653-659 | DOI: 10.24425/amm.2022.137802
Keywords finite element simulation cutting edge radius specific pressures Von Misses stresses cutting forces
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Abstract

Machining with tool that have cutting edge radius provides components with high fatigue strength, microhardness of a large surface layer and plastic deformation. Finite element simulations of the cutting process give a better knowledge of the chip generation phenomenon, heat generation in the machining area, stress and temperature field results. This study emphasizes the true importance of the mathematical model that underlies the shape of the tool in the pre-processing steps of finite element analysis. The argument is that its achievement and definition depend on the network difficulty. This research purpose is to perform simulations series of orthogonal machining with different radius and depth of cut. In this way, conclusions on the impact of these variations on the whole cutting process were drawn. The finite element application used is Deform 2D, the Lagrange incremental method and the Johnson-Cook material model. The temperature distribution, stress distribution, von Mises stress distribution, effects on specific tool pressure and wear, and fluctuations in the cutting resistance of the tool tip and C45 workpiece were analyzed.
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Authors and Affiliations

A.B. Pop
1
ORCID: ORCID
A.V. Sandu
2 3
ORCID: ORCID
A. Sachelarie
4
ORCID: ORCID
Mihail Aurel Țîțu
ORCID: ORCID
  1. Technical University of Cluj-Napoca, North University Center of Baia Mare, 62A, Victor Babeș Street, Baia Mare, Romania
  2. Gheorghe Asachi Technical University, Faculty of Materials Science and Engineering, Blvd. D. Mangeron 71, 700050 Iasi, Romania
  3. Romanian Inventors Forum, Str. Sf. P. Movila 3, 700089 Iasi, Romania
  4. Gheorghe Asachi Technical University of Iasi, Faculty of Mechanical Engineering, D. Mangeron 41, 70050, Iasi, Romania

Optimization of a Bandgap in the Ultrasonic Phononic Coating

S. Garus W. Sochacki J. Garus A.V. Sandu
Archives of Metallurgy and Materials | 2021 | vol. 66 | No 2 | 537-542 | DOI: 10.24425/amm.2021.135890
Keywords reflectance coating mechanical waves phononic crystal band gap optimization
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Abstract

This work concerns the study of the coatings for the ultrasound frequency range as a quasi one-dimensional phononic crystal structure protecting a sea object against high resolution active sonar in the frequency range most commonly found for this type of equipment. The topology of the examined structure was optimized to obtain a band gap in the 2.2-2.3 MHz frequency band. For this purpose, a genetic algorithm was used, which allows for optimal distribution of individual elements of the ultrasound multilayer composite. By optimal distribution is meant to achieve a structure that will allow minimal reflectance in a given frequency range without height reflectance peaks with a small half width. Analysis of the wave propagation was made using the Transfer Matrix Method (TMM). As part of the research, 15 and 20-layer structures with reflectance at the level of 0.23% and 0.18%, respectively, were obtained. Increasing the number of layers in the analyzed structures resulted in finding such a distribution in which a narrow band of low reflectance was obtained, such distributions could also be used as bandpass filters. The use of a genetic algorithm for designing allows to obtain modern coatings, the characteristics of which result from the structure.
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Authors and Affiliations

S. Garus
1
ORCID: ORCID
W. Sochacki
1
ORCID: ORCID
J. Garus
1
ORCID: ORCID
A.V. Sandu
2
ORCID: ORCID
  1. Czestochowa University of Technology, Department of Mechanics and Fundamentals of Machinery Design, Faculty of Mechanical Engineering and Computer Science, 73 Dąbrowskiego Str., 42-201 Częstochowa, Poland
  2. Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, Blv d. D. Mangeron 71, 700050 lasi, Romania

Correlation between Microstructure and Electrochemical Properties of Al-Si Alloys

M.G. Minciuna P. Vizureanu B. Jeż A.V. Sandu M. Nabiałek D.C. Achitei
Archives of Metallurgy and Materials | 2022 | vol. 67 | No 3 | 1067-1070 | DOI: 10.24425/amm.2022.139704
Keywords aluminium alloys microstructure X-ray diffraction corrosion Evans diagrams
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Abstract

The composition and structural modification of aluminium alloys influence their strength, tribological properties and structural stability. The phase composition of the structure as well as the characteristics of the elementary cell of each identified phase was established by X-ray diffraction, and the main objective was to determine the compositional phases, microstructure and microcomposition of the alloy. Based on the cyclic voltammograms it can be said that on the OCP interval (+1.5 V… –1.1 V), after the breakthrough potential is an intensification of the anodic process by the pronounced increase of the current density, in these conditions the Al-Si alloy has low values which means that it has a better corrosion resistance.
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Authors and Affiliations

M.G. Minciuna
1 2
ORCID: ORCID
P. Vizureanu
1 2
ORCID: ORCID
B. Jeż
3
ORCID: ORCID
A.V. Sandu
1 2
ORCID: ORCID
M. Nabiałek
3
ORCID: ORCID
D.C. Achitei
1 2
ORCID: ORCID
  1. “Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering, Blvd. Mangeron, No. 51, 700050, Iasi, Romania
  2. Universiti Malaysia Perlis (UniMAP), Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), 01000 Perlis, Malaysia
  3. Czestochowa University of Technology, Faculty of Production Engineering and Materials Technology, Department of Physics, 42-200 Częstochowa, Poland

XRD and STA Characterization of Phosphate Layers Deposited on the Carbon Steel Surface

D.-P. Burduhos-Nergis C. Bejinariu A.M. Cazac A.V. Sandu P. Vizureanu
Archives of Metallurgy and Materials | 2023 | vol. 68 | No 3 | 955-960 | DOI: 10.24425/amm.2023.145459
Keywords Zinc phosphate Manganese phosphate carbon steel XRD STA
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Abstract

Carbon steel is one of the most widely used alloys in many industries, however, its use is limited by its low corrosion resistance. Depositing a layer of phosphate on its surface improves the corrosion resistance as well as other properties, such as wear resistance, adhesion etc. Accordingly, preliminary studies demonstrated that carbon steel coated with phosphate layers can be used in the manufacture of carabiners for various fields: civil engineering, oil industry etc. Whereas, to demonstrate their capacity to operate in severe conditions related to fire rescue and extinguishing operations, it is necessary to evaluate the thermal behaviour of these materials. Thus, the main goal of this paper is to study the behaviour at high temperatures of three different types of phosphate layers deposited on carbon steel surface, by STA analysis. Also, the paper aims to study the formation of different phosphate layers by determining the types of compounds formed after the completion of the phosphating process, by XRD analysis.
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Authors and Affiliations

D.-P. Burduhos-Nergis
1
ORCID: ORCID
C. Bejinariu
1
ORCID: ORCID
A.M. Cazac
1
ORCID: ORCID
A.V. Sandu
1
ORCID: ORCID
P. Vizureanu
1
ORCID: ORCID
  1. "Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering, 41 “D. Mangeron” Street, 700050, Iasi, Romania

Phosphate Conversion Coating – A Short Review

D.-P. Burduhos-Nergis A.V. Sandu D.D. Burduhos-Nergis P. Vizureanu C. Bejinariu
Archives of Metallurgy and Materials | 2023 | vol. 68 | No 3 | 1029-1034 | DOI: 10.24425/amm.2023.145471
Keywords conversion coatings phosphate review corrosion properties
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Abstract

Phosphating is the process of depositing, by conversion, a layer of insoluble phosphate compounds, on the metal’s surface. Although phosphate coatings have been studied since the early nineteenth century, they are not only still being studied, but are an area of interest due to their many applications. The advantages of these types of coatings are well known, such as the low cost of the deposition process, the improvement of corrosion resistance properties, and the improvement of wear resistance and adhesion of further deposited layers such as paint. All this, leads to studies on the constant improvement of the properties of the phosphate coating, by modifying the parameters of the phosphating process, as well as by modifying/replacing the substances used in the phosphating solutions with “environmentally friendly” solutions. Also due to these advantages, several researchers are studying the possibility of using phosphate coatings in fields such as civil engineering or medicine (biomaterials coatings). This paper aims to present some essential aspects of phosphating and to bring to the fore the latest research on “eco-friendly” phosphating solutions and the possibility of using the phosphating process in other fields, such as the medical field. Also, the paper aims to discuss the possibility of eliminating/reducing the harmful effect that the use of phosphating has on the environment.
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Authors and Affiliations

D.-P. Burduhos-Nergis
1
ORCID: ORCID
A.V. Sandu
1
ORCID: ORCID
D.D. Burduhos-Nergis
1
ORCID: ORCID
P. Vizureanu
1
ORCID: ORCID
C. Bejinariu
1
ORCID: ORCID
  1. “Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering, 41 “D. Mangeron” Street, 700050, Iasi, Romania

Microstructural Analysis of Ambient Cured Phosphate Based-Geopolymers with Coal-Ash as Precursor

D.D. Burduhos Nergis P. Vizureanu S. Lupescu D.P. Burduhos Nergis M.C. Perju A.V. Sandu
Archives of Metallurgy and Materials | 2022 | vol. 67 | No 2 | 595-600 | DOI: 10.24425/amm.2022.137795
Keywords acid activation coal ash microstructural analysis phosphate based geopolymers
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Abstract

An alternative for Ordinary Portland cement (OPC) consumption is the production and integration of green cement. In other words, the clinker consumption has to be replaced with new low-carbon binders. A possible solution was introduced by the geopolymerisation technology. However, the alkaline activation of geopolymers offers the possibility of obtaining greener materials with high properties, superior to OPC, but due to the high price of sodium silicate, their industrial use is limited. In the past few years, a new activator has been discovered, namely phosphoric acid. This study approaches the obtaining of coal ash-based geopolymers activated with acid solution cured at room temperature. Accordingly, phosphoric acid, 85% by mass, was diluted in distilled water to obtain a corresponding activation solution for H3PO4/Al2O3 ratio of 1.0 and two types of geopolymers were ambient cured (22°C ±2°C). Moreover, to evaluate the geopolymerisation potential of this system (coal ash – phosphoric acid), SEM and EDS analysis was performed to investigate their morphologic characteristics.
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Authors and Affiliations

D.D. Burduhos Nergis
1
ORCID: ORCID
P. Vizureanu
1 2
ORCID: ORCID
S. Lupescu
1
ORCID: ORCID
D.P. Burduhos Nergis
1
ORCID: ORCID
M.C. Perju
1
ORCID: ORCID
A.V. Sandu
1 2
ORCID: ORCID
  1. "Gheorghe Asachi” Technical University of Iasi, Blvd . Mangeron, No. 51, 700050, Iasi, Romania
  2. Universiti Malaysia Perlis (UniMAP), Center of Excellence, Geopolymer & Green Technology (CeGeoGTech), School of Material Engineering, Perlis, Malaysia

Some Aspects Concerning Titanium Coverage with Hydroxyapatite

M.C. Perju C. Nejneru P. Vizureanu A.A. Aelenei A.V. Sandu L. Sachelarie M. Nabiałek
Archives of Metallurgy and Materials | 2022 | vol. 67 | No 2 | 521-527 | DOI: 10.24425/amm.2022.137785
Keywords hydroxyapatite Monetite Electrochemical and Biomimetic Deposition FTIR SEM
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Abstract

Generally, the metallic implants do not exhibit any bio-integration properties in contact with bone tissues. To improve the interfacial properties of metallic implants in contact with bone, the coatings with thin biocompatible films are used. Two methods to coating titanium implants with hydroxyapatite are described. The first is a two phase method, where by cathodic polarization is deposed a monetite film followed by an alkaline treatment when the monetite is converted to hydroxyapatite. The second method is a biomimetic deposition on an alkaline activate titanium surface, using a five time more concentrated simulated body fluid (5xSBF). After deposition this samples was drying at 120℃ and was sintered at 700℃ for three hours. Optical microscopy, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray (EDX) were used to characterize structure, morphology and compositions of the deposed films. In this study, electrochemical deposition and biomimetic deposition of hydroxyapatite are compared.
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Authors and Affiliations

M.C. Perju
1 2 3
ORCID: ORCID
C. Nejneru
1
ORCID: ORCID
P. Vizureanu
1 2 3
ORCID: ORCID
A.A. Aelenei
1
ORCID: ORCID
A.V. Sandu
1 2 3
ORCID: ORCID
L. Sachelarie
4
ORCID: ORCID
M. Nabiałek
5
ORCID: ORCID
  1. "Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering, Prof. D. Mangeron Street, No. 41, 700050, Iasi, Romania
  2. Universiti Malaysia Perlis (UniMAP), Centre of Excellence Geopolymer and Green Technology (CEGeoGTech ), Perlis, Malaysia
  3. Romanian Inventors Forum, Sf. P. Movila 3, Iasi, Romania
  4. Apollonia University of Iasi, Faculty of Dentistry, PACURARI STREET, NO. 11, 700511, Iasi, Romania
  5. Częstochowa University of Technology, Department of Physics , 42-200 Częstochowa, Poland

The Influence of Sintering Temperature on the Microstructure of Coal-Ash Based Geopolymers

D.D. Burduhos-Nergis P. Vizureanu D.C. Achitei A.V. Sandu D.P. Burduhos-Nergis M.M.A.B. Abdullah
Archives of Metallurgy and Materials | 2023 | vol. 68 | No 2 | 631-637 | DOI: 10.24425/amm.2023.142444
Keywords geopolymers alkali activation microstructural analysis sintered structures high temperature exposure
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Abstract

Currently, one of the main challenges of civil engineering and science materials engineers is to develop a sustainable substitute for Ordinary Portland Cement. While the most promising solution is provided by the geopolymerisation technology, most of the studied geopolymers are based on natural raw materials (kaolin). The metakaolin is mainly preferred because of its rapid rate of dissolution in the activator solution, easy control of the Si/Al ratio, and white color. However, its high cost prevents it from being widely used in geopolymer composites or other materials that can become an industrial alternative for Ordinary Portland Cement. Several studies have shown that geopolymers with good performance can also be obtained from secondary raw materials (industrial wastes such as coal ash or slag). This explains why countries with rapidly developing economies are so interested in this technology. These countries have significant amounts of industrial waste and lack a well-developed recycling infrastructure. Therefore, the use of these by-products for geopolymers manufacturing could solve a waste problem while simultaneously lowering virgin raw material consumption. This study evaluates the effect of replacing different amounts of coal ash with sand on the microstructure of sintered geopolymers. Accordingly, scanning electron microscopy and energy dispersive X-ray analysis were involved to highlight the morphological particularities of room-cured and sintered geopolymers.
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Authors and Affiliations

D.D. Burduhos-Nergis
1
ORCID: ORCID
P. Vizureanu
1 2
ORCID: ORCID
D.C. Achitei
1
ORCID: ORCID
A.V. Sandu
1 3
ORCID: ORCID
D.P. Burduhos-Nergis
1
ORCID: ORCID
M.M.A.B. Abdullah
4 5
ORCID: ORCID
  1. Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, D. Mangeron 41, 700050 Iasi, Romania
  2. Technical Sciences Academy of Romania, Dacia Blvd 26, 030167 Bucharest, Romania
  3. Romanian Inventors Forum, St. P. Movila 3, 700089 Iasi, Romania
  4. Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), Universiti Malaysia Perlis (UniMAP), Arau 02600, Perlis, Malaysia
  5. Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Arau 02600, Perlis, Malaysia

Study of the Effect of Intensity of Vibrations and Temperature on the Cooling Characteristics of Quenching Media

M.C. Perju C. Nejneru D.D. Burduhos-Nergis P. Vizureanu M.G. Minciuna A.V. Sandu
Archives of Metallurgy and Materials | 2023 | vol. 68 | No 3 | 997-1002 | DOI: 10.24425/amm.2023.145466
Keywords quenching media synthetic cooling media vibrations heat treatments carboxymethyl cellulose
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Abstract

Quenching technology requires the use of media with different cooling intensities and various shapes of cooling curves that show different particularities compared to that of conventional media such as water, oil, or emulsions. The use of synthetic quenching media is relatively new and also has multiple advantages such as non-flammability, safety in use and low cost. In this study, the cooling media tested was obtained by mixing 2 wt% carboxymethyl cellulose with 2 wt% NaOH in one litter of water. Moreover, three different temperatures (20°C, 40°C and 60°C) of the quenching media were evaluated. By dissolution in water, a synthetic solution with low viscosity, surfactant and lubricant was obtained. Because carboxymethyl cellulose is a biodegradable organic material, that is obtained as a by-product in the manufacture of paper, a basic substance with a preservative effect was added. According to this study, both the variation diagram of the heat transfer coefficient and the diagram of the cooling rates, during the cooling stages give important indications regarding the use of a liquid cooling medium for quenching.
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Authors and Affiliations

M.C. Perju
1
ORCID: ORCID
C. Nejneru
1
ORCID: ORCID
D.D. Burduhos-Nergis
1 2
ORCID: ORCID
P. Vizureanu
1 2
ORCID: ORCID
M.G. Minciuna
1
ORCID: ORCID
A.V. Sandu
1 2
ORCID: ORCID
  1. “Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering, Prof. D. Mangeron Street, No. 41, 700050, Iasi, Romania
  2. Romanian Inventors Forum, Sf. P. Movila 3, Iasi, Romania

Structural and Physical Characterization of New Ti-Based Alloys

I. Baltatu A.V. Sandu M.S. Baltatu M. Benchea D.C. Achitei F. Ciolacu M.C. Perju P. Vizureanu L. Benea
Archives of Metallurgy and Materials | 2022 | vol. 67 | No 1 | 255-259 | DOI: 10.24425/amm.2022.137499
Keywords new biomaterials titanium alloys biocompatible elements β phase
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Abstract

Production of Ti-based alloys with non-toxic elements give the possibility to control the market of medical applications, using alloys with appropriate properties for human body, contributing to improving the health of the population. Determination of parameters of atomic and magnetic structure of functional biomaterials demonstrating interesting physical phenomena and being promising for medical applications in a wide range of thermodynamic parameters; exploration of the role of cluster aggregation in the formation of physical properties. Paper is about the obtaining of the new titanium system alloys, the determining their characteristics and structure, and obtaining information concerning phase transitions and some mechanical properties. Ti15Mo7ZrxTa (5 wt.%, 10 wt.% and 15 wt.%) alloys developed shows a predominant β phase highlighted by optical microstructure and XRD patterns. A very low young modulus of alloys was obtained (43-51 GPa) which recommends them as very good alloys for orthopedic applications.
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Authors and Affiliations

I. Baltatu
1
ORCID: ORCID
A.V. Sandu
1 2 3
ORCID: ORCID
M.S. Baltatu
1 2
ORCID: ORCID
M. Benchea
4
ORCID: ORCID
D.C. Achitei
1 2
ORCID: ORCID
F. Ciolacu
5
ORCID: ORCID
M.C. Perju
1 2
ORCID: ORCID
P. Vizureanu
1 2
ORCID: ORCID
L. Benea
6
ORCID: ORCID
  1. “Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering, 41 “D. Mangeron” Street, 700050, Iasi, Romania
  2. University Malaysia Perlis, Centre of Excellence Geopolymer & Green Technology School of Materials Engineering, Kompleks Pengajian Jejawi 2,02600 Arau, Perlis
  3. Romanian Inventors Forum, Str. Sf. P. Movila 3, L11, 700089, Iasi, Romania
  4. “Gheorghe Asachi” Technical University of Iasi, Faculty of Mechanical Engineering, 61-63 “D. Mangeron” Street, 700050, Iasi, Romania
  5. “Gheorghe Asachi” Technical University of Iasi, Department of Natural and Synthetic Polymers, 73 Blvd. D. Mangeron, Iasi, 700050, Romania
  6. Dunărea de Jos University of Galati, Faculty of Engineering, 47 Domneasca St., 800008, Galati, Romania

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