Wyniki wyszukiwania - BazTech

1

Powierzchniowa obróbka wibro-ścierna klamek ze stopu magnezu AZ91

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

Obróbka Metalu

|

2023

|

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.

2

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.

3

Effect of number of tool shoulders on the quality of steel to magnesium alloy dissimilar friction stir welds

Khalaf Hassanein I., Al-Sabur Raheem, Derazkola Hamed Aghajani

Archives of Civil and Mechanical Engineering

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2023

|

Vol. 23, no. 2

art. no. e125, 2023

EN

Due to magnesium and iron’s immiscibility, joining magnesium alloy and steel with modern welding procedures like friction stir welding (FSW) is still complicated. Insufficient chemical bonding and mixing of raw materials in the stir zone are the main problems of joining magnesium alloy and steel. Accordingly, this paper aims to use tools with different numbers of shoulders to boost the properties of the final joint. The different tools with 1, 2, 3 and 4 shoulders were produced and used between magnesium alloy and steel during FSW. The thermal changes during the process are monitored, material flow and mechanical properties are investigated, and fractography is done on the tensile test samples. The results show that increasing shoulder numbers enhances frictional heat generation but not leads to more mechanical interlocking of base metals at interfaces. The maximum heat was generated when welded by two shoulders (600 °C), and the lowest heat was generated in one shoulder joints (540 °C). The number of shoulders for achieving the best mechanical properties has limitations. The results show that the final quality of the joint improves from one shoulder tool to three, but shows decreases at joints that were welded by more than three shoulders. The most robust tensile strength was recorded in two shoulder samples (210 MPa) with brittle fracture behavior.

4

Natryskiwane metodą APS powłoki hydroksyapatytowe do zastosowań w implantologii

Dudek Agata

Ochrona przed Korozją

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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.

5

Analysis and prediction of the impact of technological parameters on cutting force components in rough milling of AZ31 magnesium alloy

Kulisz M., Zagórski I., Weremczuk A., Rusinek R., Korpysa J.

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e1, 2022

EN

This paper presents the results of experimental study of the AZ31 magnesium alloy milling process. Dry milling was carried out under high-speed machining conditions. First, a stability lobe diagram was determined using CutPro software. Next, experimental studies were carried out to verify the stability lobe diagram. The tests were carried out for different feed per tooth and cutting speed values using two types of tools. During the experimental investigations, cutting forces in three directions were recorded. The obtained time series were subjected to general analysis and analysis using composite multiscale entropy. Modelling and prediction were performed using Statistica Neural Network software, in which two types of neural networks were applied: multi-layered perceptron and radial basis function. It was observed that milling with high cutting speed values allows for component values of cutting force to be lowered as a result of the transition into the high-speed machining conditions range. In most cases, the highest values for the analysed parameters were recorded for the component Fx, whereas the lowest were recorded for Fy. Additionally, the paper shows that a prediction (with the use of artificial neural networks) of the components of cutting force can be made, both for the amplitudes of components of cutting force Famp and for root mean square Frms.

6

Zastosowanie stopów metali lekkich w bezzałogowych statkach powietrznych

Muszyński Tomasz, Kmiotek Małgorzata, Kordos Adrian, Ficek Daniel

Obróbka Metalu

|

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.

7

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.

8

Electrodynamic treatment of structural elements made of aluminium and magnesium alloys

Lobanov Leonid M., Pashchin Nikolaj A., Kondratenko Igor P., Sidorenko Yuriy M., Ustimenko Pawel R.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2021

|

Vol. 65, No. 2

17--30

EN

The article discusses the electrodynamic treatment (EDT) of thinwalled welded structures and EDT equipment, presents results of mathematical modelling concerning the effect of EDT on stresses in welded sheets made of aluminium alloy AMg6 as well as discusses the effect of EDT on the plastic strain mechanism. In addition, the article presents tests results concerning the effect of EDT during the welding of ship structures made of AMg6 plates and discusses the role of EDT in bulge formation. In addition, the article discusses the application of EDT during the repair welding of aero-engine nacelles made of magnesium alloy ML10 and the effect of EDT on openings in an airplane wing stinger in relation to its service life.

PL

Omówiono zasadę obróbki elektrodynamicznej (EDT) cienkościennych konstrukcji spawanych i opracowaną aparaturę do EDT. Przedstawiono wyniki modelowania matematycznego wpływu EDT na stan naprężenia spawanej płyty ze stopu AMg6 oraz badań wpływu elektrodynamicznych oddziaływań na mechanizm odkształcenia plastycznego. Podano wyniki wpływu EDT na odkształcenia typu wybrzuszenie powstające podczas spawania konstrukcji okrętowych z blach AMg6. Omówiono przykład zastosowania EDT podczas spawania naprawczego gondoli silnika lotniczego z stopu magnezu ML10 oraz wpływ EDT otworów podłużnicy skrzydła samolotu na trwałość zmęczeniową.

9

Synergistic effects of alloying, homogenization, and hot extrusion on the mechanical properties of as-cast Mg–Al–Ca magnesium alloys

Nasiri Zahra, Mirzadeh Hamed, Khorrami Mahmoud Sarkari, Emamy Massoud

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

691--698

EN

Synergistic effects of partial replacement of Al with Ca, homogenization heat treatment, and hot extrusion on the microstructure and mechanical properties of Mg–(7-x)Al–xCa magnesium alloys were studied. The Mg17Al12 compound in Mg–7Al alloy, Mg17Al12 and Al2Ca compounds in AX52 alloy, Al2Ca and Mg–Al–Ca compounds in AX43 alloy, and Mg–Al–Ca compound in AX25 were characterized. The as-cast alloys were quite brittle with low strength values due to the deleterious effects of the continuous intergranular brittle constituents that completely masked the alloying effect. Homogenization resulted in the spheroidization of the eutectic constituents and gave the alloys some tensile ductility, which was remarkable for the AX43 alloy due to its fine grain size. Hot extrusion resulted in the fragmentation and dispersion of particles as well as formation of equiaxed, fine microstructures by the recrystallization processes, which led to the profound enhancements of the tensile properties in terms of both strength and elongation to failure. The product of strength and ductility of ~ 5500 MPa.% for the extruded AX43 alloy was far better than the value of ~ 314 MPa.% for the as-cast counterpart.

10

Enhanced tensile properties of as-cast Mg-10Al magnesium alloy via strontium addition and hot working

Ghorbani Fereshte, Emamy Massoud, Mirzadeh Hamed

Archives of Civil and Mechanical Engineering

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2021

|

Vol. 21, no. 2

752--760

EN

The lightweight magnesium–aluminum alloys are extensively used in automotive and aerospace industries due to their high-specific strength and low alloying cost, Grain refining via alloying and hot deformation is known as a viable technique for the enhancement of mechanical properties of these alloys. Accordingly, in the present work, grain size refinement and improvement of tensile properties of Mg-10Al magnesium alloy ingot via strontium addition (up to 1 wt%) and hot working (extrusion process) were studied. It was revealed that the addition of Sr up to 0.05 wt% leads to grain refinement of Mg-Al-Sr alloys with the resulting best strength-ductility combination. The as-cast alloys were quite brittle with total elongations well below 5% and their ultimate tensile strength (UTS) values were below 200 MPa, which was attributed to the coarse as-cast structure with a high content of brittle intergranular β-Mg17Al12 phase. It was also found that the aspect ratio of the Al4Sr particles increases by increasing strontium content, which contributes to the deterioration of tensile properties at high strontium contents. Homogenization treatment at elevated temperatures led to the dissolution of the β phase, while the thermally stable Al4Sr particles remained undissolved. The extruded alloys showed remarkably higher strength and ductility compared to the as-cast ingots, which were related to the remarkable grain refinement induced by the recrystallization processes during the hot extrusion process, the disappearance of the deleterious network of the intergranular eutectic constituent, and providing high solute Al content. As a result, UTS of ~ 406 MPa and total elongation of ~ 24% were obtained for the extruded alloy with 0.05 wt% Sr.

11

Biodegradowalne stopy na bazie Zn

Sułkowski Bartosz

Stal, Metale & Nowe Technologie

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2020

|

nr 11-12

68--71

PL

Stopy magnezu i cynku mogą być stosowane jako biodegradowalne materiały do produkcji implantów. Dzięki swoim własnościom mechanicznym oraz korozyjnym spełniają stawiane wymagania wytrzymałościowe oraz nie wytwarzają trujących substancji podczas rozpuszczania się w ludzkim ciele.

12

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).

13

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.

14

The potential of SLM technology for processing magnesium alloys in aerospace industry

Kurzynowski T., Pawlak A., Smolina I.

Archives of Civil and Mechanical Engineering

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2020

|

Vol. 20, no. 1

327--339

EN

Selective Laser Melting (SLM) of magnesium alloys is the technology undergoing dynamic development in many research centres. The results are promising and make it possible to manufacture defect-free material with better properties than those offered by the manufacturing technologies used to date. This review aims to evaluate present state as well as main challenges of using Laser Powder Bed Fusion (L-PBF) for processing magnesium alloys as an alternative way to conventional technolo-gies to manufacture parts in the aerospace industry. This literature review is the first one to outline information concerning the potential to use magnesium alloys in the aerospace industry as well as to summarise the results of magnesium alloy pro-cessing using AM technologies, in particular L-PBF. The available literature was reviewed to gather information about: the use of magnesium alloys in the aerospace industry-the benefits and limitations of using magnesium and its alloys, examples of applications using new processing methods to manufacture aerospace parts, the benefits and potential of using L-PBF to process metallic materials, examples of the use of L-PBF to manufacture aerospace parts, and state-of-the-art research into L-PBF processing of magnesium and magnesium alloys.

15

The microstructure and creep properties of as-cast Mg-Sn-Si-(Al) magnesium alloys

Rzychoń Tomasz

Archives of Civil and Mechanical Engineering

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2020

|

Vol. 20, no. 3

481--493

EN

Magnesium alloys containing rare earth metals exhibit good creep resistance up to 300 °C and good tensile properties at ambient temperature. The high cost of rare earth has led to studies regarding the creep resistance of Mg alloys with cheap alloying elements (Sn, Ca, Si) that could be substituted for Mg-RE alloys. In this paper, the influence of Si and Al on microstructure and mechanical properties of Mg-7Sn alloy was investigated using optical (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), tensile tests and creep tests at 200–250 °C. Microstructure of as-cast alloys consists of α-Mg matrix and intermetallic compounds at the interdendritic regions. Heat treatment consisting of solid solution treatment and ageing increases the tensile properties at ambient temperature due to the precipitation of the fine Mg2Sn phase. The creep resistance of aged Mg-7Sn alloy is poor. The addition of Si and Al to Mg-7Sn alloy has resulted in improving the creep resistance due to the refinement of Mg2Sn phase and the appearance of Mg2Si phase at the grain boundaries. The Mg-7Sn-1Si alloy exhibits better creep resistance at 200 °C than Mg-7Sn-5Si and Mg-7Sn-5Si-2Al alloys. The Mg-7Sn alloys with 5% Si have better creep properties at 250 °C in comparison to Mg-7Sn-1Si alloy.

16

Superplastic deformation of Mg–9Li–2Al–0.5Sc alloy after grain refinement by KoBo extrusion and cyclic forging

Dutkiewicz Jan, Kalita Damian, Maziarz Wojciech, Faryna Marek

Archives of Civil and Mechanical Engineering

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2020

|

Vol. 20, no. 4

343--353

EN

The quaternary Mg–9Li–2Al–0.5Sc alloy (in wt%) was prepared from pure components. After homogenization, the alloy was subjected to severe plastic deformation by KoBo extrusion and cyclic forging leading to grain refinement in the range of 0.5–2 µm of hexagonal close-packed (HCP) α phase. Deformed alloys showed high ultimate tensile strength near 200 MPa and good elongation in the range 30–40% at room temperature (RT). Large elongations close to 200% were obtained during the tensile test at a temperature of 200 °C. Deformed samples showed the presence of multiple voids confirming grain boundary sliding mechanism of deformation. Twins on {101-2} planes were identified using electron backscatter diffraction analysis, being in a good agreement with the earlier observation of Mg–Li and Mg–Sc alloys. Intermetallic phases such as cubic MgSc were identified in deformed alloys mostly within HCP α phase, whereas HCP MgSc2 particles were observed within body-centered cubic (BCC) β phase. Intermetallic phases were responsible for RT strengthening of alloys and slightly lower tensile elongation during superplastic deformation. Formation of the HCP α phase was observed within the BCC β phase in tensile deformed alloys. Atomic-level nucleation of HCP phase within the β phase was identified by the use of high-resolution transmission electron microscopy technique.

17

Improving the workability of materials during the dieless drawing processes by multi-pass incremental deformation

Milenin Andrij, Furushima Tsuyosh, Du Peihua, Pidvysots’kyy Valeriy

Archives of Civil and Mechanical Engineering

|

2020

|

Vol. 20, no. 3

323--336

EN

The paper explores the new method of improving the workability of materials in the dieless drawing processes. The proposed method is based on the implementation of a multi-pass incremental deformation. Moreover, in each pass, strain and strain rate sensitivity of flow stress should be positive and significant. An approach based on the finite element calculation of instability coefficient of plastic deformation and simultaneous modeling of material ductility were applied for prediction of the workability. Two dieless drawing processes have been investigated. The difference was related to the heating system-induction heating and laser heating. FE simulations and experimental tests for three materials, two magnesium alloys (MgCa0.8 and MgNi19) and pure copper were performed. It was shown that the most effective increase in workability by multi-pass deformation can be achieved using laser dieless drawing. This is possible due to the shorter heating area and, as a consequence, the larger strain rate, which leads to better stability of the deformation process.

18

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

|

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.

19

Comparison of temperature dependence of internal damping of selected magnesium alloys

Oršulová Tatiana, Palček Peter, Uhríčik Milan

Production Engineering Archives

|

2019

|

Vol. 22

7--10

EN

The research is focused on the study of the temperature dependence of the internal damping of selected magnesium alloys with different contents of aluminium - AZ31 and AZ61. These alloys are currently widely used in various types of industry, mainly in the automotive industry. It belongs to a group of materials called HIDAMETS because they have excellent damping properties. The internal damping of the samples was measured on a unique ultrasonic device constructed at Žilina University in Žilina. Specimens were measured at baseline in the temperature range from 25 °C to 400 °C. Changes in internal damping caused by varying aluminium contents in investigated alloys were noted. As the aluminium content increases, maximum internal damping is achieved due to the formation, growth and subsequent dissolution of the continuous precipitate in the microstructure.

20

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

Mola R., Cieślik M.

Archives of Foundry Engineering

|

2019

|

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.