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1

Effect of Cooling Rate on Mechanical Properties of New Multicomponent Fe-Based Amorphous Alloy During Annealing Process

Rezaei-Shahreza Parisa, Redaei Hossein, Moosavi Parisa, Hasani Saeed, Seifoddini Amir, Jeż Bartłomiej, Nabiałek Marcin

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

251--254

EN

Fe-based bulk metallic glasses (BMGs) have been extensively investigated due to their ultrahigh strength and elastic moduli as well as desire magnetic properties. However, these BMGs have few applications in industrial productions because of their brittleness at room temperature. This study is focused on the effect of cooling rate on the mechanical properties (especially toughness) in the Fe41Co7Cr15Mo14Y2C15B6 BMG. For this aim, two samples with the mentioned composition were fabricated in a water-cooled copper mold with a diameter of 2 mm, and in a graphite mold with a diameter of 3 mm. The formation of crystalline phases of Fe23(B,C)6, α-Fe and Mo3Co3C based on XRD patterns was observed after the partial crystallization process. To determine the toughness of the as-cast and annealed samples, the indentation technique was used. These results revealed that the maximum hardness and toughness were depicted in the sample casted in the water-cooled copper mold and annealed up to 928°C. The reason of it can be attributed to the formation of crystalline clusters in the amorphous matrix of the samples casted in the graphite mold, so that this decrease in the cooling rate causes to changing the chemical composition of the amorphous matrix.

2

Structure and properties of suction-cast Pr-(Fe, Co)-(Zr, Nb)-B rod magnets

Pawlik Katarzyna

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 5

art. no. e138971

EN

The rod specimens were produced from Pr9Fe50 + xCo13Zr1Nb4B23 – x (x = 0, 5, 8) alloys using the suction-casting technique. Subsequent devitrification annealing of those samples resulted in the change of their phase structure and magnetic properties. For annealed specimens of all investigated compositions, the Rietveld analyses of X-ray diffractions have shown the presence of three crystalline phases: the hard magnetic Pr2Fe11.2Co2.8B, soft magnetic α-Fe, and paramagnetic Pr1 + xFe4B4, which have precipitated within the amorphous matrix. This technique allowed us to determine the weight fractions of constituent phases. Furthermore, the microstructural changes with the alloy composition were observed. Magnetic measurements of annealed rods allowed us to calculate the switching field distributions (SFD) and δM plots in order to determine the strength and character of magnetic interactions between grains of constituent phases.

3

Ultrasonic vibrations as an impulse for glass transition in microforming of bulk metallic glass

Presz Wojciech, Kulik Tadeusz

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

100--113

EN

The paper presents the idea of the utilisation of ultrasonic vibrations in microforming at elevated temperature of a bulk metallic glasses as an impulse of additional energy for initiating a glass transition at lower than nominal temperature. The method of micro-upsetting at elevated temperature with non-uniform temperature distribution (MUNUT) was used. It is shown that applying ultrasonic vibrations on the tool could replace the part of the thermal energy needed for achieving the supercooled liquid state necessary for the microforming of bulk metallic glass. The results of research are limited to the analysis of two micro-specimens only and their final state of deformation. The commercial FEM code was used in the Thermal/Structural analysis class to determine the temperature distribution within the micro-specimen and to justify the linear approximation of this distribution. It was shown that the application of ultrasonic vibrations at 20 kHz frequency and the amplitude PP = 36.5 μm under the experiment conditions lowered the transformation temperature by approx. 32 °C. Results suggesting that applying ultrasonic vibrations could be also used as the tool which would provide additional energy for the transformation at the limited area of the micro-product.

4

Amorphous materials in the production of new implants

Kiljan A., Liptakova T.

Production Engineering Archives

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2018

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Vol. 18

50--53

EN

Amorphous materials based on magnesium are new materials for potential biomedical application, especially for new implants, as they bear resemblance to titanium implants. Mg66Zn30Ca4 alloy has specific properties, especially mechanical and corrosive, therefore, it has biomedical application as its properties are better than that of other materials. The following paper describes amorphous alloy based on magnesium, properties and shows how to produce amorphous samples of Mg66Zn30Ca4.

5

Phase Transition and Plasticity Enhancement of Ti-Cu-Based Bulk Metallic Glasses

Wang L., Wang X., Zhang G., Sun X.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 1

387--391

EN

In this paper, we report the complex crystallization kinetics of phase transition happening in Ti-Cu-based bulk metallic glasses (BMGs), which play significant roles in the glass formation with respect to their low reduced glass transition temperatures, Trg. The first exothermic event just occurs when annealing the BMG samples in the supercooled liquid region, leading to the Avrami exponent deviating from conventional modes affected by the residual amorphous phase. For Ti43Cu43Ni7Zr7 BMG, the plasticity can be improved by pre-annealing at a sub-Tg temperature of 623K (≈50K below Tg) for 0.5 hour, however, deteriorated by 1 hour annealing, which could be related to the change in stability of this BMG against crystallization with different pre-annealing times.

6

Isothermal Stability and Selected Mechanical Properties of Zr48Cu36Al8Ag8 Bulk Metallic Glass

Błyskun P., Latuch J., Kulik T.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 3

1749--1753

EN

The aim of this work was to investigate the influence of isothermal annealing on the amorphous structure stability of the Zr48 Cu36 Al8 Ag8 alloy. A series of continuous heating examinations was performed on the differential scanning calorimeter in order to determine the temperature limits for isothermal annealing series where the time to crystallization was measured. The obtained results were calculated and a time-temperature-transformation diagram was created and discussed. Static compression test as well as microhardness measurements of the as-quenched samples gave a mechanical properties results supplement. The measured properties (σc = 1800 MPa and 614 HV0.05) are comparable to the literature results for this alloy. Fractographic observations with the scanning electron microscope were also performed in order to prove some plasticity observed during the strength tests.

7

Effect of Zr Purity and Oxygen Content on the Structure and Mechanical Properties of Melt-Spun and Suction-Cast Cu46Zr42Al7Y5 Alloy

Kozieł T., Latuch J., Cios G., Bała P.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2B

1215--1219

EN

The effect of oxygen content in zirconium on the structure and mechanical properties of the Cu46Zr42Al7Y5 alloy, in the form of melt-spun ribbons and suction-cast rods, was investigated. Two types of Zr, rod and crystal bar of different nominal purities and oxygen contents, were used to synthesize the alloy by arc melting. Rapidly solidified ribbons were produced by melt spinning and their amorphous structures were confirmed by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). Bulk samples in the form of rods were cast using a special water-cooled suction casting unit attached to the arc melting system. XRD and DSC studies proved the amorphous structure of the bulk alloy synthesized from low-oxygen Zr and partial crystallization of the same alloy for high-oxygen Zr. In both bulk samples, uniformly distributed crystalline particles were identified as yttrium oxides. Higher mean compressive strength of amorphous alloy was observed. The hardness of amorphous phase was close to 500 HV1 in both bulk alloys, while the hardness of crystalline dendritic areas, observed in the alloy synthesized from high oxygen Zr, was lower by about 50 HV1.

8

Corrosion of Biocompatible Mg66+xZn30-xCa4 (x=0.2) Bulk Metallic Glasses

Nowosielski R., Cesarz-Andraczke K., Sakiewicz P., Maciej A., Jakóbik-Kolon A., Babilas R.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

807--810

EN

The aim of this paper was to investigate the corrosion resistance of Mg66Zn30Ca4 and Mg68Zn28Ca4 metallic glasses and evaluate the ability of this amorphous alloy use for medical applications as biodegradable medical implants. Taking into account the amount of Mg, Zn, Ca elements dissolved in multielectrolyte physiological fluid (MPF) from Mg66+xZn30-xCa4 (x=0.2) alloys the daily dose of evolved ions from alloys components was determined. Additional goal of the paper was determination of corrosion rate (Vcorr) and amount of hydrogen evolved from amorphous magnesium alloys in simulated environment of human body fluids during 24h immersion and during electrochemical tests. Corrosion studies were done in the multielectrolyte physiological fluid (MPF) at 37°C. The amount of hydrogen evolved [ml/cm2] and corrosion rate Vcorr [mm/year] of amorphous Mg66Zn30Ca4 and Mg68Zn28Ca4 alloys were compared. The work also presents characterization of Mg-based bulk metallic glasses structure in the form of 2 mm thickness plates. Samples structure was analyzed by means of X-ray diffraction. Fracture and surface morphology of magnesium alloy samples were identified using scanning electron microscopy.

9

Bulk metallic glasses based on magnesium to potential biomedical application

Kiljan A., Nowosielski R.

Selected Engineering Problems

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2015

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nr 6

41--44

EN

The paper presents some informations about materials for biomedical application. The study was performed on ternary Mg-based alloys. The Mg66Zn30Ca4 glassy alloy was prepared in the form of rods by pressure die casting method of molten alloy into water cooled copper mold. This alloy is potential material for biomedical application.

10

Cu47Ti34Zr11Ni8 amorphous alloy fabricated by the pressure die casting method

Nowosielski R., Guwer A., Gawlas-Mucha A.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 70, nr 1

5--12

EN

Purpose: The aim of present work is characterization of the pressure die casting, fabrication and testing of structure and properties Cu47Ti34Zr11Ni8 ingot and amorphous and crystalline alloys prepared in the form of rods. Design/methodology/approach: The preliminary ingot was prepared by using the method of arc melting. Rods were fabricated by the pressure die casting method. The melting point and liquidus temperatures of the ingot were determinated in the thermal analysis DTA. Analysis of the microstructure of a pre-alloy was carried out by using the EDS method. X-ray diffraction was used to study structure of fabricated ingot and rods. Hardness was measured by using the Vickers method and compression tests were also performed. Findings: Modernization of the pressure die casting station in the form of housing, which was made from the plexiglass, allowed to keep a protective atmosphere during casting, after that alloys did not oxidate. The X-ray diffraction investigations were indicated that the examined quaternary rods with 2 mm and 3 mm diameters had amorphous structure. The rod with diameter of 4 mm had crystalline structure. The phases occur in ingot and crystalline rods were identified by using X-ray card. Rod about 4mm diameter demonstrated the highest hardness. The rod with diameter of 3 mm demonstrated the highest compressive strength - 1798 MPa. Research limitations/implications: In the future, the research of mechanical properties of Cu47Ti34Zr11Ni8 amorphous rod will be performed. Moreover, further attempts of a fabrication of the Cu47Ti34Zr11Ni8 amorphous rod about diameter higher than 3 mm, will be prepared. Practical implications: A manufactured housing enables the production of bulk metallic glasses about different chemical compositions, by preventing possible oxidations of elements. Originality/value: Modernization of position for the pressure die casting into copper mould. A comparison of properties of Cu47Ti34Zr11Ni8 amorphous and crystalline rods.

11

Influence of silver on glass forming ability and mechanical properties of Zr–Cu–Al alloys

Błyskun P., Cieślak G., Kowalczyk M., Latuch J., Kulik T.

Inżynieria Materiałowa

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2015

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Vol. 36, nr 4

154--159

EN

The work focuses on studying the influence of silver content on the glass forming ability and the mechanical properties of the Zr48Cu36Al16 – xAgx alloys (x = 0, 2, 4, ..., 16 at. %). Rods with a diameter of 3 mm were manufactured by the copper mould casting. X-ray diffraction studies (Fig. 1) revealed that samples with 6÷14 at. % of silver content were fully amorphous. Differential scanning calorimetry (Fig. 3) allowed selecting the alloy that possessed the best glass forming ability on the basis of the supercooled liquid region width (ΔTx). The Zr48Cu36Al6Ag10 alloy exhibited ΔTx = 91 K. Mechanical properties of the alloys were characterized by means of Vickers microhardness (Fig. 5) and room temperature compression tests (Fig. 6). The highest value of microhardness was detected for the partially crystalline Zr48Cu36Al16 alloy (791 HV). However, the highest compression strength was measured for the Zr48Cu36Al12Ag6 alloy (σc = 1881 MPa). It should be noticed that a plastic strain was observed in the fully amorphous alloys. On the other hand, partially crystalline samples cracked catastrophically without any observable plastic strain. These studies revealed that the silver content increase resulted in the microhardness and the compression strength decrease. Good mechanical performance and satisfying glass forming ability of the fully amorphous alloys examined at this work seems to be promising set of properties for structural applications. However, the Zr48Cu36Al4Ag12 is the most promising one.

PL

Praca dotyczy określenia wpływu dodatku srebra na zdolność do zeszklenia i właściwości mechaniczne stopów Zr48Cu36Al16 – xAgx (x = 0, 2, 4, ..., 16% at.). Pręty o średnicy 3 mm odlewano do formy miedzianej. Badania dyfrakcyjne promieni rentgenowskich wykazały, że próbki o zawartości srebra 6÷14% at. są w pełni amorficzne. Pozostałe stopy miały zbyt małą zdolność do zeszklenia, aby ulec pełnej amorfizacji w formie o średnicy 3 mm. Różnicowa kalorymetria skaningowa pozwoliła wskazać stopy o największej zdolności do zeszklenia wyznaczanej na podstawie szerokości zakresu cieczy przechłodzonej (ΔTx). Stop Zr48Cu36Al6Ag10 cechował się największą zdolnością do zeszklenia ΔTx = 91 K. Właściwości mechaniczne stopów scharakteryzowano za pomocą pomiarów mikrotwardości i statycznej próby ściskania w temperaturze pokojowej. Największszą mikrotwardość zmierzono dla próbki częściowo krystalicznej Zr48Cu36Al16 (791 HV). Jednak największą wytrzymałość na ściskanie uzyskano dla próbki w pełni amorficznej Zr48Cu36Al12Ag6 (σc = 1881 MPa). Należy podkreślić, że dla wszystkich próbek amorficznych odnotowano pewien zakres odkształcenia plastycznego. Natomiast wszystkie próbki częściowo krystaliczne pękały katastroficznie bez odkształcenia plastycznego. Badania wykazały, że wzrost zawartości srebra powoduje zmniejszenie zarówno mikrotwardości, jak i wytrzymałości na ściskanie, ale w pewnym zakresie (6÷15% at.) wyraźnie poprawia zdolność do zeszklenia. Dobre właściwości mechaniczne i zadowalająca zdolność do zeszklenia stopów w pełni amorficznych, badanych w tej pracy, wydają się obiecującym zestawieniem właściwości w przypadku przyszłych zastosowań konstrukcyjnych. Stop o składzie Zr48Cu36Al4Ag12 okazał się optymalnym kandydatem.

12

Fractographic discoveries: investigation of bulk metallic glasses fracture surfaces after static compression test

Błyskun P., Cieślak G., Kowalczyk M., Latuch J., Kulik T.

Inżynieria Materiałowa

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2015

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Vol. 36, nr 2

54--59

EN

The aim of these studies was to broaden the knowledge of bulk metallic glasses failure mechanisms. Two glass forming systems: Zr48Cu36Al16 – xAgx (x = 0, 6, 12, 16 at. %) and Cu48Zr36Ag16 – yTiy (y = 3, 5, 8 at. %) were selected for the studies. Rod shape samples with a diameter of 3 mm were produced from pure elements by the copper mould casting. X-ray diffraction allowed to determine the crystalline phase presence within the samples (Fig. 1). Both partially crystalline and fully amorphous samples were subjected to the static compression tests. The fractography of the resultant scraps was performed by the scanning electron microscopy. The studies reveal several new issues and confirm a few already known related to deformation and fracture mechanisms of metallic glasses. Authors carefully observed and insightfully discussed issues like: main fracture surface exclusiveness for vein-like patterns (Fig. 2), plastic strain implementation by the slip bands proliferation (Fig. 3), vein-like pattern development degree dependence on the fracture stress (Fig. 4), temperature rise relics presence on the main fracture surface (Fig. 5) or determining the origin of a crystalline phase just by the fracture surface observations (Fig. 6, 7). The results presented in this manuscript might be useful for future materials expertise that would potentially be done on metallic glass scraps from failed constructions.

PL

Celem pracy było poszerzenie wiedzy o mechanizmach zniszczenia masywnych szkieł metalicznych. Do badań wybrano dwa układy szkłotwórcze: Zr48Cu36Al16 – xAgx (x = 0, 6, 12, 16 at. %) i Cu48Zr36Ag16 – yTiy (y = 3, 5, 8 at. %). Z czystych pierwiastków wytworzono pręty o średnicy 3 mm metodą odlewania do formy miedzianej. Badania dyfrakcji promieni rentgenowskich pozwoliły ustalić obecność fazy krystalicznej w próbkach. Zarówno próbki częściowo krystaliczne, jak i w pełni amorficzne zostały poddane statycznej próbie ściskania w temperaturze pokojowej. Za pomocą skaningowej mikroskopii elektronowej przeprowadzono obserwacje fraktograficzne otrzymanych przełomów. Badania te umożliwiły potwierdzenie kilku znanych zagadnień oraz odkrycie nowych zjawisk związanych z odkształcaniem i pękaniem szkieł metalicznych. Autorzy dokonali obserwacji oraz omówienia takich kwestii, jak: wyłączność głównej powierzchni pęknięcia na obecność struktury żyłowej, realizowanie odkształcenia plastycznego przez mnożenie pasm poślizgu, zależność stopnia rozwinięcia struktury żyłowej od naprężenia pękania, obecność pozostałości po wzroście temperatury na głównej powierzchni pęknięcia czy określanie pochodzenia fazy krystalicznej na podstawie obserwacji powierzchni pęknięcia. Wyniki przedstawione w pracy mogą być przydatne w przypadku przyszłych ekspertyz materiałowych wykonywanych na złomach elementów konstrukcyjnych ze szkła metalicznego.

13

Structure and Properties of Mg-Cu-(Y,Ca) Bulk Metallic Glasses

Babilas R., Cesarz-Andraczke K., Nowosielski R.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 4

2645--2650

EN

The work presents preparation methods, structure characterization and mechanical properties analysis of Mg-based bulk metallic glasses in as-cast state and after crystallization process. The studies were performed on Mg60Cu30Y10 and Mg37Cu36Ca27 glassy alloys in the form of plates and rods. The X-ray diffraction investigations revealed that the tested samples with different thicknesses and shapes were amorphous. The characteristics of the fractured surfaces showed mixed fractures with the “river” and “mirror” patterns, which are characteristic for the glassy materials and some “smooth” areas. The samples of Mg37Cu36Ca27 alloy presented a two-stage crystallization process, but addition of Y caused a single stage crystallization behavior. Qualitative phase analysis from the X-ray data of examined alloys annealed at 473 K enabled the identification of Mg, Mg2Cu, Cu2Mg and CaCu crystalline phases. The changes of compressive strength as a function of annealing temperature for studied rods were stated. The best mechanical properties including microhardness and compressive strength were obtained for the alloy with the addition of Y in as-cast state.

PL

W pracy przedstawiono wyniki badań struktury i wybranych własności masywnych szkieł metalicznych na osnowie magnezu. Badania przeprowadzono na próbkach w stanie wyjściowym oraz po procesie wygrzewania. Do badań wybrano dwa trójskładnikowe stopy magnezu z dodatkiem itru lub wapnia o następującym składzie chemicznym:Mg60Cu30Y10 oraz Mg37Cu36Ca27. Badania rentgenowskie potwierdziły, że analizowane próbki w postaci płytek i prętów posiadają strukturę amorficzną. Obserwacje mikroskopowe wybranych obszarów powierzchni przełomów płytek i prętów pozwoliły na wyodrębnienie stref o morfologii przełomów „gładkich” i „łuskowych”. Analiza procesu krystalizacji wykazała występowanie pojedynczego etapu krystalizacji dla szkła metalicznego Mg60Cu30Y10 związanego z wydzielaniem się fazy Mg2Cu oraz dwuetapowego procesu krystalizacji dla stopu Mg37Cu36Ca27, w którym zidentyfikowano fazę Cu2Mg i CaCu. Największą wytrzymałość na ściskanie oraz mikrotwardość uzyskano dla próbek szkła metalicznego z dodatkiem itru w stanie bezpośrednio po odlaniu.

14

The production attempt of Fe-Nb-B-Zr and Fe-Nb-B-Y system alloys by die pressure casting method

Pilarczyk W., Kucharczyk M.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

222-228

EN

Purpose: The purpose of this article was to investigate the possibility of the production of Fe-Nb-B bulk metallic alloys with additions of yttrium and zirconium elements. Furthermore, this paper tends to present the structure and selected properties of obtained alloys. In this article the influence of an argon atmosphere on casting process was observed too. Design/methodology/approach: The production attempts were performed on Fe-Nb-B-Zr and Fe-Nb-B-Y system alloys in form of a plate. Master alloy ingots with compositions of Fe72B22Y4Nb2 and Fe71(Nb0.8Zr0.2)6B23 were prepared by induction melting of pure Fe, Nb, B, Y and Fe, Nb, B, Zr elements in an argon atmosphere. The ingots have been crushed and then the investigated material was cast with and without a protective atmosphere. The investigated materials were cast in form of a plate with thickness of 1 mm. The structure analysis of the studied materials in as-cast state was carried out using X-ray diffraction (XRD) and microscopic observation. The thermal properties of the alloys were examined by DSC methods. The measurments of the hardness were performed with the Vickers method. Findings: The Fe-Nb-B-Y and Fe-Nb-B-Zr system alloys in form of a plate were produced by die pressure casting method. The investigation methods revealed that the studied as-cast alloys were crystalline. The structure of the obtained plates is rather fine-grained and there were not found any impurities and undesirable phases inside the materials. The results of calorimetric curves confirm that all tested samples are crystalline. Practical implications: To extend the potential applications of the Fe-based BMGs, amorphous alloys with larger critical sizes and better processability are required. The Fe-Nb-B-Zr and Fe-Nb-B-Y bulk metallic glasses obtained by die pressure casting method can be used for production of telecommunications devices, sensors or low-energy transformers. These materials exhibit excellent mechanical and soft magnetic properties. Originality/value: An overall presentation of an influence of the yttrium and zirconium additions on the attempt of forming Fe72B22Y4Nb2 and Fe71(Nb0.8Zr0.2)6B23 alloys. The chemical composition of these alloys was tested in our laboratory for the first time.

15

Structure and corrosion properties of Mg70-xZn30Cax(x=0.4) alloys for biomedical applications

Nowosielski R., Cesarz K., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

|

Vol. 58, nr 1

7--15

EN

Purpose: The main objective of the paper was to investigate the structure and corrosion properties of amorphous and crystalline Mg-based alloys for biodegradable implants. This paper presents a preparation method and the structure, microhardness and corrosion properties characterization of Mg70Zn30and Mg66Zn30Ca4 alloys in the form of plates. Design/methodology/approach: The studied samples were prepared by the pressure die-casting to copper mould. The structure of the both alloys was examined by X-ray diffractometry (XRD) and a scanning electron microscope (SEM). The thermal properties of the samples were examined using a differential scanning calorimeter (DSC). In addition, corrosion properties research (immersion tests) were performed in a physiological fluid. Microhardness was measured using the Vickers microtester. Findings: The results of X-ray diffraction investigations confirmed that the sample of Mg66Zn30Ca4 alloy is amorphous and sample of Mg70Zn30 alloy has crystalline structure. Immersion tests of both samples have shown homogeneous progress of corrosion. The changes of a structure caused by calcium addition resulted in an increase of microhardness for sample Mg66Zn30Ca4 compared with the sample of Mg70Zn30 alloy. Research limitations/implications: Results of immersion tests are dependent of used fluid. In this paper used physiological (multielectrolyte) fluid to corrosion studies, which composition is similar to the electrolyte composition of the blood plasma. Chemical composition of fluid used in corrosion studies could be affected to results of studies. Therefore it is appropriate to carry out comparative studies such as electrochemical corrosion studies. Practical implications: Mg-based alloys can be applied as the medical implants. The chemical composition of the samples Mg66Zn30Ca4 and Mg70Zn30 was chosen, because they meet the requirements of a biodegradable material, that is, material, which after completing their stability function will dissolve in the body of the patient without the harmful effects on health. Originality/value: Crystalline and amorphous magnesium alloys are examined as a material for biodegradable medical implants. This new concept is an alternative to previously used conventional implant materials. New concept doesn’t require re-operation, and allows foreign object to remain in the human body.

16

Investigations of temperature distribution in metallic glasses fabrication process

Januszka A., Nowosielski R., Pusz A.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

360--366

EN

Purpose: The goal of paper is investigations of temperature distribution which is appearance during fabrication process of metallic glasses. In present work particular attention focused on system for registration of temperature distribution. Design/methodology/approach: Bulk metallic glasses in the composition as the following: Fe36Co36B19.2Si4.8Nb4 were fabricated by the die casting method. Distribution of temperature was carried out by a prototype measure system. Investigations were realized for casting process of the samples in form of rods with diameter 2, 3 and 4 mm. Temperature distributions were executed for series of samples. Moreover, investigations also enclosed structure characterization tested by X-ray diffraction and SEM. Findings: On the base of temperature distribution curves it can be observed that during casting of metallic glasses a temperature gradient have been occur. It should be note that prototype system allows to measure temperature only in cooper mould not inside of sample. Diffraction patterns confirmed that structure of tested samples was amorphous. Electron microscope observations revealed fracture morphology which is characteristic fore glassy structure. Practical implications: Analysis of temperature during casting process plays an important role in effective fabrication of metallic glasses. Cooling rate can be estimated on the base of results these analyse. Knowing the cooling rate, it could be possible to determine the glass forming ability of studied alloy. Originality/value: Investigations which have been taken in present work are novelty for the sake of optimization of casting process not only for metallic glasses, but also for nanocrystalline engineering materials.

17

Fabrication of ternary Ca-Mg-Zn bulk metallic glasses

Nowosielski R., Borowski A., Guwer A., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 56, nr 2

67--74

EN

Purpose: The paper describes the preparation, structure and thermal properties of ternary Ca-Mg-Zn bulk metallic glass in form of as-cast rods. Design/methodology/approach: The investigations on the ternary Ca-Mg-Zn glassy rods were conducted by using X-ray diffraction (XRD), scanning electron microscopy (SEM) which energy dispersive X-ray analysis (EDS). Findings: The X-ray diffraction investigations have revealed that the studied as-cast rod was amorphous. The fractures of studied alloy could be classified as mixed fracture with indicated “river” and “smooth” fractures. Both type of the fracture surfaces consist of weakly formed “river” and “shell” patterns and “smooth” regions. The “river” patterns are characteristic for metallic glassy alloys. Practical implications: The studied Ca-based bulk metallic glasses is a relatively new group of material. Ca-based bulk metallic glasses are applied for many applications in different elements. Ca-based bulk metallic glasses have many unique properties such as low density (~2.0 g/cm³), low Youn g’s modulus ( ~20 to 30 GPa). The elastic modulus of Ca-b ased BMGs is comparable to that of hum an bone s, and Ca, Mg, and Zn are biocompatible. These features make the Ca-Mg-Zn–based alloys attractive for use in biomedical applications. Originality/value: Fabrication of amorphous alloy in the form of rod ternary Ca-Mg-Zn alloy by pressure die casting method.

18

The study of structure and glass forming ability of Zr-based amorphous alloy

Pilarczyk W.

Archives of Materials Science and Engineering

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2013

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Vol. 63, nr 1

19--25

EN

Purpose: This paper tends to present the structure and thermal analysis of selected Zr-based amorphous alloy for welding processes. Design/methodology/approach: The studies were performed on Zr-Cu-Ni-Al system alloy in form of plate. The structure analysis of the studied materials in as-cast state was carried out using XRD method. The thermal properties of the as-cast alloy were examined by DSC and DTA methods. The parameters of GFA included Trg, ΔTx, α, β, γ, δ and S were calculated. Findings: The Zr-based amorphous alloy in form of plate with good GFA was produced by die pressure casting method. The investigation methods revealed that the studied as-cast alloy was amorphous. Although, there is probability of crystallites existence which could not be detected by XRD method. The literature study and calculated GFA parameters indicated that the Zr55Cu30Ni5Al10 alloy exhibits good GFA and thermal stability. It is confirmed that these parameters could be used to determine GFA of tested amorphous alloy for welding processes. This Zr-based BMG could be used as tested material for laser welding process. Research limitations/implications: It is very difficult to obtain a Zr-based BMG with large sizes. Usually, the difficulties of the production of zirconium amorphous alloy are connected with the fact that the constituent elements of the analyzed materials have a high chemical affinity for oxygen, and have different melting points. For this reason, the process of producing BMG in zirconium matrix require the using of additional technology to provide specific conditions for the melting and casting. Practical implications: These obtained values of GFA parameters can suggest that studied alloys are suitable materials for further practical application at welding process. Originality/value: The success formation and investigation of the casted Zr-based BMG. The chemical composition of Zr55Cu30Ni5Al10 alloy was tested first time in our laboratory.

19

Thermal properties of Fe-based bulk metallic glasses

Nowosielski R., Januszka A., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

349--354

EN

Purpose: The aim of paper is presentation of results bulk metallic glasses thermal properties such as temperatures typical for glassy transition and thermal conductivity. Design/methodology/approach: Investigations were realized for Fe₃₆Co₃₆B_{19.2>/sub>Si_4.8Nb samples with dimension 3 mm in diameter. Bulk test pieces were fabricated by copper mold casting method. Thermal analysis of master alloy (DTA) and samples in as-cast state (DSC) was realized. For amorphous structure confirmation the X-ray diffraction phase analysis (XRD) was realized. Additionally scanning electron microscopy (SEM) micrographs were performed in order to structure analysis. Thermal conductivity was determined by prototype measuring station. Findings: The XRD and SEM analysis confirmed amorphous structure of samples. Broad diffraction “halo” was observed for every testing piece. Fracture morphology is smooth with many “veins” on the surface, which are characteristic for glassy state. DTA analysis confirmed eutectic chemical composition of master alloy. Thermal conductivity measurements proved that both samples have comparable thermal conductivity. Practical implications: The FeCo-based bulk metallic glasses have attracted great interest for a variety application fields for example precision machinery materials, electric applications, structural materials, sporting goods, medical devices. Thermal conductivity is useful and important property for example computer simulation of temperature distribution and glass forming ability calculation. Originality/value: The obtained results confirm the utility of applied investigation methods in the thermal and structure analysis of examined amorphous alloys. Thermal conductivity was determined using the prototype measuring station, which is original issue of the paper. In future, the measuring station will be expanded for samples with different dimensions.}

20

The study of glass forming ability of Fe-based alloy for welding processes

Pilarczyk W.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 52, nr 2

83--90

EN

Purpose: This paper tends to present the thermal analysis and structure of selected Fe-based bulk metallic glasses for welding processes. Design/methodology/approach: The studies were performed on Fe-Co-B-Si-Nb alloy in form of plate and rod. Master alloy ingot with compositions of Fe37.44Co34.56B19.2Si4.8Nb4 was prepared by induction melting of pure Fe, Co, B, Si and Nb elements in argon atmosphere. The investigated material was cast in form of plate with thickness 0.5 mm and rod with diameter 3 mm. The structure analysis of the studied materials in as-cast state was carried out using X-ray diffraction (XRD). The thermal properties: glass transition temperature (Tg), onset crystallization temperature (Tx) and peak crystallization temperature (Tp) of the as-cast alloys were examined by differential scanning calorimetry (DSC) and melting temperature (Tm), liquidus temperature (Tl) by differential thermal analysis (DTA) methods. The parameters of glass forming ability included reduced glass transition temperature (Trg), supercooled liquid region (ΔTx), α, β, y, δ and stability (S) were calculated. Findings: The Fe-based bulk metallic glasses in form of plate and rod with good glass forming ability were produced by die pressure casting method. The investigation methods revealed that the studied as-cast bulk metallic glasses were amorphous. These materials exhibit good glass-forming ability. The calculated GFA parameters indicated that the slightly best glass-forming ability has Fe37.44Co34.56B19.2Si4.8Nb4 alloy in form of rod. It is confirmed that these parameters could be used to determine glass forming ability of tested amorphous alloy for welding processes. Research limitations/implications: It is difficult to obtain a bulk metallic glasses in form of plate and rod with large sizes. Various empirical parameters have been proposed to specify the glass forming ability of bulk metallic glasses. Several GFA indicators have been determined by measuring the characteristic thermal parameters. A few simple criteria were calculated to explain the GFA of tested alloys. Practical implications: These obtained values of GFA parameters can suggest that studied alloys are suitable materials for further practical application at welding process. Originality/value: The success formation and investigation of the casted Fe-based bulk metallic glasses. The chemical composition of Fe37.44Co34.56B19.2Si4.8Nb4 alloy were tested first time.