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1

Comparative analysis of microstructure and selected properties of WC-Co-Cr coatings sprayed by high-velocity oxy fuel on S235 and AZ31 substrates

Jonda Ewa, Myalska-Głowacka Hanna, Łatka Leszek, Szymański Krzysztof, Dziekońska Małgorzata

Materials Science Poland

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2024

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Vol. 42, No. 1

32--41

EN

The purpose of this work was to carry out comparative studies of WC-Co-Cr coatings deposited using the high velocity oxy fuel (HVOF) method onto two types of substrate material: structural steel S235 and magnesium alloy AZ31. The influence of the substrate material type on the microstructure, phase composition, crystallite size, porosity, Vickers microhardness, instrumental hardness (HIT), Young’s modulus (EIT), and fracture toughness was investigated. For both substrates, the deposited coatings deposited were characterized with fine-grained and compact microstructure. The X-ray diffraction (XRD) revealed presence of following phases: WC, W2C, Co0.9W0.1, and Co3W9C4. The WC phase was the most desirable and stable one with crystallites were below 100 nm. On the other hand, the size of the W2C crystallites was below 30 nm. The coatings obtained showed porosity values equal to 2.3 ± 0.4 vol% and 2.8 ± 0.7 vol% for AZ31 and S235, respectively. The average Vickers microhardness for both types of sample was appproximately 1200 HV0.3. The average HIT values for carbide particles and metallic matrix were around 29 GPa and 6.5 GPa, respectively. In the case of EIT, it was around 620 GPa and 190 GPa for WC and Co-Cr, respectively. The differences between coatings were negligible. The EIT value for both coatings was equal to 344 ± 11 GPa. The fracture toughness was around 4.5 MPa · m1/2 in both cases. The investigations revealed that it is possible to replace steel substrate material with a much lighter equivalent, in this case AZ31 alloy, without deterioration of the coating properties.

2

Experimental investigation and machining analysis of Mg/TiC composites during EDM

Dash Dharmeswar, Devarajaiah Devarasiddappa, Dash Santosh Kumar, Samanta Sutanu, Rai Ram Naresh

Composites Theory and Practice

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2024

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R. 24, nr 1

9--16

EN

Electrical discharge machining (EDM) is one of the prominent non-conventional machining processes used to machine metal matrix composites. Mg/TiC composites are found in many industrial applications and conventional machining of the same is highly challenging. This paper aims to study the machinability analysis of Mg/TiC composites using EDM with pulseon time (Ton), pulse-off time (Toff) and input current (I) as the process variables with the material removal rate (MRR) and surface roughness (SR) as the performance measures. Stir cast Mg-alloy reinforced with TiC (0, 5, 10, 15 and 20) by weight was used as the workpiece. The EDM experiments were conducted as per L25 orthogonal array (OA) and the results were analyzed to study the effect of the process variables on MRR and SR. The parametric study showed that SR increases linearly with Ton and is attributed to larger craters produced at a higher pulse energy. MRR was also observed to grows with the rise in Ton as more material melts due to high-intensity pulses. As per the ANOVA results, Ton was found to be the most influential process variable affecting SR and MRR with a 79% and 34% contribution, respectively. Surface morphology investigations using SEM micrographs revealed the presence of globules and sphere-shaped metal deposits and were found responsible for increased SR.

3

Powierzchniowa obróbka wibro-ścierna klamek ze stopu magnezu AZ91

Gołąbczak Marcin, Woźniak Kazimierz, Wincenciak Mariusz, Gołąbczak Andrzej, Jędrzejczak Anna, Niewiadomski Michał

Obróbka Metalu

|

2023

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nr 3

27--33

PL

Przedstawiono wyniki badań dotyczące wpływu warunków obróbki wibro-ściernej na kształtowanie morfologii i struktury geometrycznej powierzchni klamek ze stopu magnezu AZ91. Zakres prezentowanych badań obejmował obróbkę odlewanych klamek ze stopu magnezu w wygładzarce wibro-ściernej z zastosowaniem różnego typu kształtek ściernych ceramicznych, żywicznych i porcelanowych oraz ich wybłyszczania i suszenia granulatem z kolby kukurydzy w suszarce wibracyjnej. Pomiary morfologii i struktury geometrycznej powierzchni klamek ze stopu magnezu wykonano po każdym etapie obróbki wibro-ściernej z zastosowaniem mikroskopu i profilometru optycznego.

EN

In the paper there were presented the results of studies on the influence of vibration-abrasive treatment conditions on the morphology and geometric structure of surfaces of handles made of magnesium alloy AZ91. The scope of the presented studies included attempts to process cast magnesium alloy handles in a vibratory-abrasive smoothing machine using various types of ceramic, resin and porcelain abrasive fittings as well as their polishing and drying with granules from the corn cob in a vibratory dryer. The morphology and geometric structure of the surface of the magnesium alloy handles were measured after each step of the vibration-abrasive treatment using a microscope and an optical profilometer.

4

Effects of SPD by Biaxial Alternate Forging on the Tensile Properties and Microstructure of AZ31B Magnesium Alloy

Shin Young-Chul, Ha Seong-Ho, Shah Abdul Wahid

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

97--101

EN

The forming limit of AZ31 alloy, a representative Mg-Al-Zn-based wrought alloy, and the effect of severe plastic deformation (SPD) by examining the microstructure change caused by dynamic recrystallization led by high temperature and high dislocation density at 300℃ using a biaxial alternate forging (BAF) were investigated in this study. As a result of BAF test for AZ31 Mg alloy, significant cracks on the ends of workpieces occurred after 7 passes. The microstructure of as-extruded specimen showed the non-uniform distribution of the relatively coarse grains and the fine grains considered to be sub-grains. However, as the number of passes increases, the area of coarse grains gradually disappeared and the fine grains became more dominant in the microstructures. The result of tensile test for workpieces with each forging pass showed an increase in strength depending on pass number was shown with a slight increase of elongation. The Electron Backscatter Diffraction (EBSD) results exhibited that, the microstructure showed the presence of coarse grains and twins after only 1 pass, while the grains appeared to be significantly refined and uniformly distributed after 3 pass, at which the strength and elongation began to increase, simultaneously.

5

Investment Casting of AZ91 Magnesium Open-Cell Foams

Kapłon Honorata, Dmitruk Anna, Naplocha Krzysztof

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

11--16

EN

The process of investment casting of AZ91 magnesium alloy open-cell porosity foams was analysed. A basic investment casting technique was modified to enable the manufacturing of magnesium foams of chosen porosities in a safe and effective way. Various casting parameters (mould temperature, metal pouring temperature, pressure during metal pouring and solidifying) were calculated and analysed to assure complete mould filling and to minimize surface reactions with mould material. The foams manufactured with this method have been tested for their mechanical strength and collapsing behaviour. The AZ91 foams acquired in this research turned out to have very high open porosity level (>80%) and performed with Young’s modulus of ~30 MPa on average. Their collapsing mechanism has turned out to be mostly brittle. Magnesium alloy foams of such morphology may find their application in fields requiring lightweight materials of high strength to density ratio or of high energy absorption properties, as well as in biomedical implants due to magnesium’s high biocompatibility and its mechanical properties similar to bone tissue.

6

Influence of Defects on Deformation Behavior of High-Pressure Die-Casting Magnesium Alloys

Braszczyńska-Malik Katarzyna

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 2

10--14

EN

The results of investigations of defects in AME-series magnesium alloys produced by the high-pressure die-casting method are presented. The analyzed magnesium alloys contain about 5 wt% aluminum and 1-5 wt% rare earth elements introduced in the form of mischmetal. The casts were fabricated using a regular type cold-chamber high-pressure die-casting machine with a 3.2 MN locking force. The same surfaces of the casts were analyzed before and after the three-point bending test in order to determine the influence of the gas and shrinkage porosity on the deformation behavior of the alloys. The obtained results revealed that the most dangerous for the cast elements is the shrinkage porosity, especially stretched in the direction perpendicular to the that of the tensile stress action. Additionally, the influence (Mg) solid solution and its interaction on the cracking process was described [alpha]  of deformation twins arise in the dendrites of the primary.

7

Natryskiwane metodą APS powłoki hydroksyapatytowe do zastosowań w implantologii

Dudek Agata

Ochrona przed Korozją

|

2022

|

nr 6

182--185

PL

Ze względu na możliwe zastosowanie biodegradowalnych implantów ze stopów magnezu w ortopedii oraz w celu zwiększenia ich odporności na korozję można pokryć ich powierzchnię bioaktywnymi powłokami, np. hydroksyapatytowymi. W pracy zaproponowano wprowadzenie modyfikacji w zakresie natryskiwanych plazmowo metodą APS (atmosferic plasma spraying) powłok hydroksyapatytowych, polegającej na zastosowaniu dodatku 20% wag. ceramiki YSZ (yttria stabilized zirconia). Analizowano morfologię oraz mikrostrukturę powłok za pomocą mikroskopu cyfrowego KEYENCE VHX-7000, a także grubość – miernikiem Testan DT-20 AN 120 157 oraz skład fazowy – z użyciem dyfraktometru Seifert T-T. W celu potwierdzenia możliwości zastosowania powłok w implantologii przeprowadzono badania odporności korozyjnej w symulowanym płynie ustrojowym, odwzorowującym warunki ludzkiego organizmu.

EN

Taking into account the potential use in orthopedics and obtaining an increase in corrosion resistance of biodegradable implants made of magnesium alloys, bioactive coatings, e.g. hydroxyapatite, can be applied to their surface. In this paper, a modification of the APS (atmosferic plasma spraying) plasma spraying method was proposed for hydroxyapatite coatings by adding 20% wt. YSZ ceramics (yttria stabilized zirconia). The morphology and microstructure of the coatings were analysed using the KEYENCE VHX-7000 digital microscope, thickness using the Testan DT-20 AN 120 157 meter and phase composition using a Seifert T-T diffractometer. In order to confirm the possibility of using coatings in implantology, corrosion resistance tests were carried out in a simulated body fluid mapping the conditions of the human body.

8

Vibration analysis during AZ31 magnesium alloy milling with the use of different toolholder types

Korpysa Jarosław, Zagórski Ireneusz

Eksploatacja i Niezawodność

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2022

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Vol. 24, no. 3

489--501

EN

Machining vibrations are an important issue as they occur in all types of machining processes. Due to its negative impact on machining results, this phenomenon is undesirable, and so there have been continuous efforts to find solutions that will minimise it, and thus improve the stability and safety of the machining process. The paper attempts to determine the impact of toolholder type and cutting condition on the vibrations generated while milling an AZ31 magnesium alloy. The tests were performed using the three most common types of toolholders: ER, Shrink Fit and hydraulic. The vibration displacement and acceleration signals were analysed based on parameters such as Peak-to-Peak, Peak, and Root Mean Square. Composite Multiscale Entropy was also applied to check the stability of cutting processes and define the level of signal irregularity. To determine the frequencies of vibrations and to detect chatter vibrations Fast Fourier Transform was performed. This provides information on the stability and enables vibrations to be minimized by avoiding unfavourable cutting conditions.

9

Optimization of process parameters in turning of magnesium AZ91D alloy for better surface finish using genetic algorithm

Pradeep Kumar Madhesan, Venkatesan Rajamanickam, Manimurugan Manickam

Acta Innovations

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2022

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no. 43

54--62

EN

This research examined at the optimum cutting parameters for producing minimum surface roughness and maximum Material Removal Rate (MRR) when turning magnesium alloy AZ91D. Cutting speed (m/min), feed (mm/rev), and cut depth (mm) have all been considered in the experimental study. To find the best cutting parameters, Taguchi's technique and Response Surface Methodology (RSM), an evolutionary optimization techniques Genetic Algorithm (GA) and Non-dominated Sorting Genetic Algorithm-II (NSGA-II) were employed. GA gives better results of 34.04% lesser surface roughness and 15.2% higher MRR values when compared with Taguchi method. The most optimal values of surface roughness and MRR is received in multi objective optimization NSGA-II were 0.7341 µm and 9460 mm3/min for the cutting parameters cutting speed at 140.73m/min, feed rate at 0.06mm/min and 0.99mm depth of cut. Multi objective NSGA-II optimization provides several non-dominated points on Pareto Front model that can be utilized as decision making for choice among objectives.

10

Ocena właściwości antykorozyjnych powłok konwersyjnych wytworzonych na magnezie i jego stopach w procesie elektrolitycznego utleniania plazmowego– przegląd

Florczak Łukasz

Ochrona przed Korozją

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2021

|

nr 10

320--331

PL

W pracy wskazano na wciąż duże zainteresowanie magnezem i jego stopami z Al, Zn, Mn, Zr oraz pierwiastkami ziem rzadkich oraz krótko opisano kierunki aktualnych badań dotyczących metody elektrolitycznego utleniania plazmowego (PEO) jako metody zwiększającej odporność antykorozyjną stopów magnezu. Zaprezentowano metody pomiarowe służące do oceny właściwości antykorozyjnych powłok konwersyjnych wytworzonych w procesie PEO na magnezie i jego stopach. Opisano zalety i wady metod nieelektrochemicznych i elektrochemicznych, w tym: test w komorze solnej, test zanurzeniowy (ocena wyglądu, ubytek masy, zbieranie wodoru) oraz pomiary potencjału obwodu otwartego (OCP), polaryzacji potencjodynamicznej (PDP), analizę Motty-Schottky’ego oraz elektrochemiczną spektroskopię impedancyjną (EIS). Wykazano przewagę techniki EIS nad niszczącymi pomiarami elektrochemicznymi, która pozwala na prowadzenie nieniszczących pomiarów długoterminowych wytworzonych powłok ochronnych. Dokonano przeglądu roztworów korozyjnych, najczęściej stosowanych do oceny właściwości antykorozyjnych powłok konwersyjnych oraz wskazano rozcieńczony roztwór Harrisona (DHS), jako odpowiednie medium do badań cienkich powłok (~10 μm) wytworzonych metodą PEO na stopach magnezu przeznaczonych do zastosowań w warunkach przemysłowych. Zwrócono uwagę na konieczność właściwego doboru czasu trwania pomiarów korozyjnych w zależności od właściwości powłoki oraz jej potencjalnego zastosowania.

EN

The paper shows the unfailing interest in magnesium and its alloys with Al, Zn, Mn, Zr and rare earth elements, and briefly describes the directions of current research on the method of plasma electrolytic oxidation (PEO) as a method of increasing the corrosion resistance of magnesium alloys. The measurement methods for the assessment of anti-corrosion properties of conversion coatings produced in the PEO process on magnesium and its alloys are presented. Described are the advantages and disadvantages of non-electrochemical and electrochemical methods, including: salt spray test, immersion test (assessment of appearance, weight loss, hydrogen collection) and measurements of the open circuit potential (OCP), potentiodynamic polarization (PDP), Motta-Schottky analysis and electrochemical impedance spectroscopy (EIS). The advantage of the EIS technique over destructive electrochemical measurements has been demonstrated, which allows for non-destructive long-term measurements of the produced protective coatings. The most common corrosive solutions used to assess the anti-corrosive properties of conversion coatings were reviewed and the diluted Harrison solution (DHS) was indicated as a suitable medium for testing thin coatings (~10 μm) produced by the PEO method on magnesium alloys intended for use in industrial conditions. The necessity of proper selection of the duration of corrosion measurements depending on the properties of the coating and its potential application has been pointed out.

11

Zastosowanie stopów metali lekkich w bezzałogowych statkach powietrznych

Muszyński Tomasz, Kmiotek Małgorzata, Kordos Adrian, Ficek Daniel

Obróbka Metalu

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2021

|

nr 2

42--49

PL

W ostatnich latach obserwuje się znaczny wzrost użycia bezzałogowych statków powietrznych (BSP) w licznych zastosowaniach komercyjnych, a także wojskowych. Obecnie szacuje się, że na świecie istnieje przeszło 10 mln tego typu obiektów, wykorzystywanych od celów od hobbystycznych po profesjonalne, których wartość przekracza wiele milionów dolarów. BSP, zwane powszechnie dronami muszą cechować się małą masą i dużą sprawnością układu napędowego i zasilania, które pozwalają na długi czas nieprzerwanej pracy w powietrzu zwiększając obszar potencjalnych zastosowań. Jest to szczególnie istotne w przypadku obiektów latających używanych w zastosowaniach profesjonalnych. W zależności od zastosowania i liczności serii, do ich budowy wykorzystuje się wiele różnych materiałów w szczególności kompozytów. Jednakże bezzałogowe aparaty latające używane do celów militarnych, a także komercyjnych, np. w transporcie i rolnictwie muszą dodatkowo cechować się wytrzymałą i stabilną konstrukcją pozwalającą na przenoszenie dużych obciążeń. Z tej przyczyny coraz częściej do budowy BSP używa się stopów metali lekkich w szczególności aluminium, magnezu i tytanu. Ważnym argumentem przemawiającym za używaniem stopów metali lekkich są również względy ekologiczne gdyż niedostatecznie jeszcze są rozwinięta procesy recyklingu materiałów kompozytowych.

EN

In recent years, there has been a significant increase in the use of unmanned aerial vehicles(UAV) in numerous commercial as well as military applications. Currently, it is estimated that there are more than 10 million such objects in the world, used for purposes ranging from hobby to professional, with a value exceeding many millions of dollars. UAV, commonly referred to as drones, must be characterized by low weight and high efficiency of the propulsion and power systems that allow for long periods of continuous operation in the air increasing the area of potential applications. This is especially important for flying objects used in professional applications. Depending on the application and the number of series, many different materials are used for their construction, especially composites. However, unmanned aerial vehicles used for military as well as commercial purposes, such as transport and agriculture, must additionally feature a robust and stable design to carry heavy loads. For this reason, lightweight metal alloys, in particular aluminum, magnesium and titanium, are increasingly being used to build UAV. An important argument for the use of light alloys are also ecological considerations as recycling processes for composite materials are still underdeveloped.

12

Optimization of tribology parameters of AZ91D magnesium alloy in dry sliding condition using response surface methodology and genetic algorithm

Beniyel M., Sivapragash M., Vettivel S. C., Senthil Kumar P., Ajith Kumar K. K., Niranjan K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 1

art. no. e135835

EN

In the present research, the wear behaviour of magnesium alloy (MA) AZ91D is studied and optimized. MA AZ91D is casted using a die-casting method. The tribology experiments are tested using pin-on-disc tribometer. The input parameters are sliding velocity (1‒3 m/s), load (1‒5 kg), and distance (0.5‒1.5 km). The worn surfaces are characterized by a scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). The response surface method (RSM) is used for modelling and optimising wear parameters. This quadratic equation and RSM-optimized parameters are used in genetic algorithm (GA). The GA is used to search for the optimum values which give the minimum wear rate and lower coefficient of friction. The developed equations are compared with the experimental values to determine the accuracy of the prediction.

13

Struktura geometryczna powierzchni próbek ze stopu magnezu AZ31 po polerowaniu oraz modyfikacji biopolimerami wytwarzanymi metodą CVD

Gołąbczak Marcin, Maksim Przemysław, Skowron Marcin, Kyzioł Karol, Gołąbczak Andrzej, Działo Adam, Szkatulski Piotr

Obróbka Metalu

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2020

|

nr 4

49--54

PL

W artykule przedstawiono wyniki badań dotyczące porównania parametrów struktury geometrycznej powierzchni (SGP) próbek ze stopu magnezu AZ31 po polerowaniu oraz po wytworzeniu na ich powierzchniach różnego typu biokompatybilnych powłok ochronnych. Zakres prezentowanych badań obejmował proces przygotowania próbek do ich cięcia metodą WEDM, polerowania krążkami ściernymi, chemicznego trawienia oraz modyfikację ich powierzchni poprzez wytworzenie biopolimerowych powłok ochronnych metodą chemicznego osadzania z fazy gazowej CVD.

EN

In this paper the results of investigations concerning the comparison of surface geometric structure parameters of samples made of magnesium alloy AZ31 were presented. The samples were polish and coated of various types of biocompatible protective coatings. The scope of presented studies included the process of sample preparation by WEDM cutting, abrasive disc polishing, chemical pickling and modification of their surface by producing biopolymer protective coating by chemical deposition from gas phase (CVD).

14

Fatigue Properties of AZ31 and WE43 Magnesium Alloys

Junak G.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

721--726

EN

The paper presents low-cycle fatigue (LCF) characteristics of selected magnesium alloys used, among others, in the automotive and aviation industries. The material for the research were bars of magnesium alloys AZ31 and WE43 after hot plastic working. Due to their application(s), these alloys should have good/suitable fatigue properties, first of all fatigue durability in a small number of cycles. Low-cycle fatigue tests were carried out on the MTS-810 machine at room temperature. Low-cycle fatigue trials were conducted for three total strain ranges Δεt of 0.8%, 1.0% and 1.2% with the cycle asymmetry factor R = –1. Based on the results obtained, fatigue life characteristics of materials, cyclic deformation characteristics σa = f(N) and cyclic deformation characteristics of the tested alloys were developed. The tests have shown different behaviors of the tested alloys in the range of low number of cycles. The AZ31 magnesium alloy was characterized by greater fatigue life Nf compared to the WE43 alloy.

15

Characterization of Corrosion and Stress Corrosion Cracking of AE44 Magnesium Alloy

Sozańska M., Mościcki A., Chmiela B.

Archives of Metallurgy and Materials

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2020

|

Vol. 65, iss. 1

479--484

EN

The paper presents the susceptibility of AE44 magnesium alloy to electrochemical corrosion and stress corrosion cracking (SCC). The evaluation of the intensity of the interaction of the corrosive environment was carried out using the corrosion tests and the Slow Strain Rate Test (SSRT). Corrosion tests performed in 0.1 M Na2 SO4 solution (immersion in solution and under cathodic polarization conditions) revealed that the layer of corrosion products was much thicker after immersion test. The results of SSRT showed that the AE44 alloy deformed in the solution was characterized by higher plasticity compared to the alloy deformed in the air after immersion in solution. Moreover, the fractures were characterized by different morphology. In the case of an alloy deformed in the solution under cathodic polarization many microcracks on the fracture were observed, which were not observed in the case of the alloy deformed in the air.

16

Impact Strength of AE-type Alloys High Pressure Die Castings

Braszczyńska-Malik K., Malik M. A.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

5--8

EN

The results of the Charpy impact test of AE-type magnesium alloys produced by the high pressure die casting method are presented. Three alloys with different weight fractions of rare earth elements (RE; e.g. 1, 3 and 5 wt%) and the same mass fraction of aluminium (5 wt%) were prepared. The casts were fabricated using a typical cold chamber high pressure die casting machine with a 3.8 MN locking force. Microstructural analyses were performed by means of a scanning electron microscope (SEM). The impact strength (IS) was determined using a Charpy V hammer with an impact energy equal to 150 J. The microstructure of the experimental alloys consisted of an [alpha]-Mg solid solution and Al11RE3, Al10Ce2Mn7 and Al2RE intermetallic compounds. The obtained results show the significant influence of the rare earth elements to aluminium ratio on the impact strength of the investigated materials. Lower the RE/Al ratio in the chemical composition of the alloy results in a higher impact strength of the material.

17

Fabrication and effect of Mg–Zn solid solution via Zn foil interlayer alloying in FSW process of magnesium alloy

Sahu Prakash Kumar, Pal Sukhomay, Das Bipul, Shi Qingyu

Archives of Civil and Mechanical Engineering

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2020

|

Vol. 20, no. 4

589--603

EN

The present study demonstrates the friction stir welding (FSW) process can be used as a mechanical alloying tool to fabricate a solid solution. An attempt has been taken for alloying the AM20 Mg base matrix using Zn at the weld zone during friction stir welding. Successful joints with sound mechanical properties and enhanced quality attributes are observed in the welds. Use of Zn alloying element at the nugget zone, the joint efficiency reached 90% to that of the base material and also which is about 25% more than the strength obtained in the case of without alloying element set of experiments. The addition of Zn alloy to Mg substrate forms Mg–Zn binary solid solution reinforcing intermetallic compounds, namely MgZn and Mg7Zn3 resulting in improved joint properties. This research work also reports the investigative outcomes, namely flow in the joint area, metallurgical deviation, microstructural modification, and diffusion of the constituent alloying element during the welding process. The targeted objective was effectively accomplished and the Zn alloyed stir area can fulfil the required application. The findings from the selective alloying process may be relevant for the implementation of industrial users over Mg alloys using a FSW process with better weldability and improved strength.

18

Microscopic Analysis of Layers Containing Mg2Si and Mg17Al12 Phases Fabricated on AZ91 Through Thermochemical Treatment

Mola R., Cieślik M.

Archives of Foundry Engineering

|

2019

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iss. 3

119--124

EN

The thermochemical treatment applied to improve the surface properties of AZ91 consisted in heating the material in contact with AlSi10Mg powder at 445 oC for 30 min. During heat treatment process the powder was held under pressure to facilitate the diffusion of the alloying elements to the substrate and, accordingly, the formation of a modified layer. Two pressures, 1 MPa and 5 MPa, were tested. The resultant layers, containing hard Mg2Si and Mg17Al12 phases, were examined using an optical microscope and a scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (EDS). The experimental data show that the layer microstructure was dependent on the pressure applied. A thicker, three-zone layer (about 200 μm) was obtained at 1 MPa. At the top, there were Mg2Si phase particles distributed over the Mg17Al12 intermetallic phase matrix. The next zone was a eutectic (Mg17Al12 and a solid solution of Al in Mg) with Mg2Si phase particles embedded in it. Finally, the area closest to the AZ91 substrate was a eutectic not including the Mg2Si phase particles. By contrast, the layer produced at a pressure of 5 MPa had lower thickness of approx. 150 μm and a two-zone structure. Mg2Si phase particles were present in both zones. In the upper zone, Mg2Si phase particles were regularly distributed over the Mg17Al12 intermetallic phase matrix. The lower zone, adjacent to the AZ91, was characterized by a higher volume fraction of Mg2Si phase particles distributed over the matrix composed mainly of Mg17Al12. The alloyed layers enriched with Al and Si had much higher hardness than the AZ91 substrate.

19

Analiza struktury złącza PA38/AZ31 wytworzonego metodą zgrzewania dyfuzyjnego

Mola R., Cieślik M., Bartos J.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2018

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z. 90 [298], nr 3

367--376

PL

W artykule przedstawiono analizę struktury złącza stop aluminium (PA38)–stop magnezu (AZ31) wytworzonego metodą zgrzewania dyfuzyjnego. Za pomocą mikroskopu optycznego i elektronowego mikroskopu skaningowego przeprowadzono szczegółowe badania metalograficzne. Skład chemiczny strefy złącza określono metodą mikroanalizy rentgenowskiej (EDS). Wykonano również pomiary mikrotwardości metodą Vickersa łączonych materiałów i strefy złącza. W wyniku procesu zgrzewania uzyskano trwałe połączenie. Strefa złącza, o grubości ok. 50 µm, miała budowę dwuwarstwową. Od strony stopu PA38 w złączu zidentyfikowano grubszą warstwę (ok. 40 µm) fazy międzymetalicznej Al3Mg2, od strony stopu AZ31 cieńszą warstwę (ok. 10 µm) fazy międzymetalicznej Mg17Al12. W mikrostrukturze strefy złącza od strony stopu PA38 na tle osnowy fazy Al3Mg2 stwierdzono obecność drobnych cząstek fazy Mg2Si. Od strony stopu AZ31, na tle fazy Mg17Al12, obserwowano lokalnie iglaste cząstki fazy Al-Mn-Si. Na podstawie pomiarów mikrotwardości stwierdzono, że strefa złącza zbudowana głównie z faz międzymetalicznych Mg-Al charakteryzuje się kilkukrotnie wyższą mikrotwardością w porównaniu z łączonymi stopami.

EN

This paper presents the results of the microstructure investigation of the aluminium alloy (PA38) – magnesium alloy (AZ31) joint fabricated by diffusion bonding. The structure of the bonding zone was examined using optical microscopy and scanning electron microscopy. The chemical composition of the bonding zone was determined by energy dispersive X-ray microanalysis. The microhardness measurements of the alloys and the bonding zone was also conducted. As a result of the diffusion bonding process the alloys were joined together. The bonding zone with a thickness of about 50μm had two-layer structure. In the bonding zone the thicker layer (about 40μm) of Al3Mg2 intermetallic phase was observed on the PA38 alloy side. The thinner layer (about 10 μm) of Mg17Al12 intermetallic phase was observed on the AZ31 alloy side. In the area of the bonding zone close to the PA38 alloy fine particles of Mg2Si phase were found in the matrix of Al3Mg2. In the bonding zone close to the AZ31 alloy locally a needle-shaped particles of the Al-Mn-Si phase were observed over the Mg17Al12 phase matrix. The results of microhardness measurement revealed that the bonding zone composed mainly of Mg-Al intermetallic phases layers had much higher microhardness than the joined alloys.

20

Wykorzystanie metody akumulacyjnego walcowania pakietowego do wytwarzania lekkich wielowarstwowych materiałów Al-Mg-Al

Wierzba A., Mróz S., Szota P., Stefanik A., Mola R.

Rudy i Metale Nieżelazne Recykling

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2018

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R. 63, nr 5

11--17

PL

W pracy zaproponowano wykonanie lekkiego materiału wielowarstwowego składającego się z trzech warstw, w którym zewnętrzne warstwy stanowiło aluminium w gatunku 1050A, natomiast środkowa warstwa wykonana była ze stopu AZ31. Przygotowany materiał wielowarstwowy poddano odkształceniu za pomocą metody ARB w 4 przepustach przy temperaturze 400°C. Przyjęto, że początkowa grubość pakietu wynosiła 3 mm (po 1 mm dla każdego komponentu). Walcowanie zrealizowano w walcarce laboratoryjnej duo D150 z zastosowaniem symetrii i asymetrii prędkości obrotowych walców. W pracy wykazano, że wprowadzenie asymetrii do metody ARB dla badanego materiału Al-Mg-Al, wpływa na rozdrobnienie struktury w porównaniu do procesu symetrycznego.

EN

The study has proposed the production of a lightweight multilayered material composed of three layers, in which the external layers is made up by aluminium in grade 1050A, while the central layer is made of the alloy AZ31. The prepared multilayered material was subjected to deformation by the ARB method in 4 rolling passes. The initial packet thickness was assumed to be 3 mm (1 mm for each component), and the rolling process was conducted at a temperature of 400°C. The rolling was carried out on a D150 laboratory two-high mill equipped with individual working roll drives, which enabled a rotational roll speed asymmetry to be introduced into the rolling process. As a result of the rolling carried out, a multilayered material was obtained, which was characterized by a refined structure.