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1

Investigations of stress and strain state of aluminum alloys during a hot extrusion and patterns of structure and feature formation

Aghbalyan Suren G., Bagdasaryan Vazgen, Vasilyan Gayane A., Wyczółkowski Rafał

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2024

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Vol. 33, No. 1

3--16

EN

This paper investigates the stress and strain state as well as formation processes of structure and features of aluminum alloys during the hot extrusion. It has been shown that during the hot extrusion the ring layers of an extruded element experience not only longitudinal and transverse deformations, but also a slip. The slip increases from inner layers to the surface layer. The tensile principal stresses and the sum of slip deformations also increase. It has been also demonstrated that at the exit of the pressing part the tensile principal stresses have different directions, forming an angle with extruder axis, which also increases towards the surface. In conclusion, it has been stated that the main radial and circumferential deformations act as restraining deformations.

2

Analysis of the Effect of Vacuum Pressure Variations on the Fluidity, form Ability, Hardness, and Density of the RTV 10A Silicon Rubber Composites with 30% Talc

Suprihanto Agus, Caesarendra Wahyu, Wibowo Dwi Basuki, Bartoszuk Marian, Varga Gyula

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 4

12--22

EN

RTV 10A silicone rubber composites have many applications in forming many medical products and one of the recent applications is for orthotic insoles. This is because the RTV silicon rubber has excellent flexibility, elasticity, and resistance against splitting. However, these mechanical properties still need improvement when applied in certain medical applications. One way to improve mechanical properties is by adding talc. The process of mixing silicon rubber with talc requires special techniques to prevent the formation of porosity that may lead to unexpected mechanical properties. This porosity occurs due to trapped air during the mixing process or pouring into molds. Efforts to eliminate this porosity include Vacuum Die Casting (VDC) techniques. This study presents the mechanical properties improvement of RTV 10A silicon rubber composite with the addition of using 30% talc. The objective is to achieve a more convenient orthotic insole to reduce the pain in human foot joints during walking due to planar stress. This study aims to reduce the porosity and minimize the trapped air by adding 30% talc into RTV 10A silicone rubber composite using VDC. In the experiment, the pressure variation was determined at -0.04 MPa, -0.06 MPa, -0.08 MPa, and -0.1 MPa through a mold size of 45 mm in diameter and thickness of 7 mm. Fluidity, density, porosity, and hardness were tested during the experiment. The results show that by decreasing vacuum pressure, the density and the hardness increase. This is because the size and distribution of porosity are decreased and more homogeny. Furthermore, it also produces higher fluidity. However, the porosity of the specimen after vacuum casting is not partially filled.

3

Staliwo stopowe wysokomanganowe w zastosowaniach na odlewane elementy infrastruktury kolejowej

Wróbel Tomasz, Bartocha Dariusz, Jezierski Jan, Sobula Sebastian, Kostrzewa Krzysztof, Feliks Edward

Stal, Metale & Nowe Technologie

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2023

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nr 1-2

30--34

PL

W publikacji przedstawiono charakterystykę staliwa stopowego wysokomanganowego, potocznie określanego mianem staliwa Hadfielda. Staliwa z tej grupy w warunkach wzrostu ciśnienia lub obciążenia, np. w wyniku uderzenia, wykazują dużą skłonność do tzw. umocnienia zgniotem, objawiającego się zwiększeniem powierzchniowej twardości i odporności na zużycie przy zachowaniu ciągliwości rdzenia.

EN

The paper presents the characteristics of a high-manganese alloy cast steel, commonly referred to as Hadfield cast steel. Cast steels of this group demonstrate a high tendency to the so-called strain hardening under the conditions of pressure or load increase, e.g. as a result of an impact, which is manifested by an increase in surface hardness and wear resistance while maintaining the ductility of the core. This is decisive for the applicability of a high-manganese cast steel for the castings of hammers and liners for coal mills and other mills, crusher cones, working elements of construction machines as well as cast elements of turnouts. In particular, the paper presents the chemical composition and usable properties of a high- -manganese cast steel intended for use in railway infrastructure as well as the characteristics of its microstructure finally shaped by heat treatment.

4

Performance of self-compacting concrete cast in hot weather conditions

Khalil Hossam S., Abd Elhameid Mohamed W., Badawy Amal A.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2023

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Vol. 32, No. 3

284--302

EN

This work focused on how self-compacting concrete (SCC) performs in situ in hot weather conditions at an ambient temperature of about 35°C. Tests for the rheological properties and compressive and splitting tensile strength aspects were carried out. The results of SCC mix ingredients on the rheological and hardened features of SCC mix were studied. Variations in the amount of portland cement content (CC), water to cement ratio (w/c), coarse to fine aggregate ratio (C : F), chemical admixture ratio, and pozzolanic admixture ratio were considered. Optimum values were obtained for these ingredients, which satisfied the SCC rheological characteristics and gave a 28-day compressive strength of 42 MPa, and 52 MPa after 28 days and 56 days, respectively. These optimum constituent values were 450 kg·m–3 of cement, 0.45 water cementitious ratio, and a coarse to fine material ratio of 1 : 0.8, a high range superplasticizer of 2%, and a mineral admixture of either 5% silica fume or 25% fly ash as a substitute for a similar amount cement.

5

Digitally designed casting ring and sprue system - a contemporary approach to the casting process in dentistry

Penchev P.

Archives of Materials Science and Engineering

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2023

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Vol. 119, nr 1

31--41

EN

Purpose: The current paper aims to present a new casting approach in dentistry by eliminating some conventional preliminary procedures and digitalising the process as much as possible. Design/methodology/approach: The experiment uses six digital crown patterns. They are aligned with each other and to the wall of a virtual casting ring. Then a digital sprue system is created. The object alignment and sizes are revised, and the optimal correlation is set. Finally, a single virtual object is created and is 3D printed of light curing acrylic resin suitable for casting, invested, and cast. Findings: The castings that are achieved have good quality and no defects. At the same time, the virtual designing and aligning of the patterns and all the components of the sprue system and casting ring save much time and allows better precision to be achieved. All these facts allow better control of the casting process results, making the process faster, more predictable, and more accurate. Research limitations/implications: The limitations of this study concerns pattern selection. It is well-known that the acrylic resin sublimates and expands massively during a temperature rise, which may cause mould fracture. This obstacle is very representative as solid objects with higher volumes are examined. This may enforce alignment revision or even temperature rate modification. Practical implications: Suggested approach will be very useful for daily dental laboratory practice by optimizing the working time of the dental technician, making the denture production process faster, more predictable, and more accurate. As a result, the process optimizes the working process in dental offices, by allowing shortening the time of each visit and treatment plan terms. Originality/value: Presented approach reveals some new opportunities for dental technicians to substitute the conventional raw stages of sprue system fabrication with digital planning and designing. This allows dental technicians to take advantage of the full potential of digital technologies.

6

The Influence of the Casting Process on Shaping the Primary Structure of Mg-Li Alloys

Bednarczyk Iwona

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

137--144

EN

This paper presents the results of a study to determine the influence of casting parameters (cooling rate in the casting mould, casting temperature) on the primary structure of Mg-4%Li-1%Ca alloy ingots. The macro- and microstructure analysis of the Mg-4%Li-1%Ca alloy was performed using light and electron microscopy techniques. Microhardness measurements were made for the Mg-4%Li-1%Ca alloy and phase identification in the Mg-4%Li-1%Ca alloy was made using X-ray phase analysis.

7

Quantitative Prediction of Air Entrainment Defects in Casting Filling Process

Yin Yajun, Xie Yao, Song Yingchen, Shen Xu, Ji Xiaoyuan, Zhou Jianxin

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

117--126

EN

Air entrainment defect is a common type of defect in the casting process, which will seriously affect the quality of the casting. Numerical simulation technology can predict the occurrence of casting defects according to the evolution law of liquid metal in the process of filling and solidification. The simulation of air entrainment process is a hot and difficult issue in the field of numerical simulation. The evolution law of air entrainment and the tracking of induced bubbles in the process of metal filling are still lacking. So is the quantitative prediction of trained gas. In this paper, based on the numerical simulation software of Inte CAST, this paper proposes an algorithm for air entrainment search and tracking, which is used to develop a quantitative prediction system for air entrainment. The feasibility of the system is verified through the simulation calculation of the typical test pieces of the air entrainment and the prediction of air entrainment defects of the casting in the process of filling is obtained through the simulation calculation of the actual casting, which can provide a certain guiding role for the optimization of the process in the production practice.

8

An innovative approach to fabrication with photo-cured resins by shell-printed-core-casting

Szymczyk Emil, Rećko Maciej, Dzierżek Kazimierz, Sapiołko Karol

Acta Mechanica et Automatica

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2023

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Vol. 17, no. 4

485--489

EN

Modified LCD-based method was used to print three-dimensional (3D) elements. This innovative method combines printing the external shell and filling, thus obtaining mould by casting resin. In order to compare the properties of prints obtained with this method with the ones fabricated in a standard procedure, we conducted bending tests of vertically/horizontally printed and shell-printed cast specimens. The shell-cast samples showed higher flexural strength and larger values of apparent Young’s modulus. The presented results also concern the kinetics of curing samples obtained with different fabrication routes.

9

Computer modelling of the ablation casting process and prediction of the strength properties of AC-42000 castings

Małysza Marcin, Puzio Sabina, Major-Gabryś Katarzyna, Głowacki Mirosław, Wilk-Kołodziejczyk Dorota, Kamińska Jadwiga

Computer Methods in Materials Science

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2022

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Vol. 22, No. 2

79--88

EN

The demand for castings with superior properties has compelled the development and optimization of manufacturing technologies. By further developing already known techniques, we are able to contribute to the introduction of new research possibilities. The article presents the methodology of conducting simulation tests of the gravity casting process into sand moulds with the use of ablation. The ablation technique consists in spraying water through evenly spaced nozzles onto a mould into which the liquid casting alloy has been poured. The conducted research focuses on an alloy from the group of Al-Si alloys. In order to compare the effects of different techniques, additional tests were carried out for gravity casting into sand and metal die moulds. At the same time, virtual experiments were conducted to develop a simulation methodology for ablation casting technology, taking into account mould degradation. Additionally, the possibility of predicting the final mechanical properties of various manufacturing technologies was tested. Destructive tests were carried out to determine the mechanical properties in the cast samples, as well as microstructure tests and secondary dendrite spacing. The results of the mechanical tests are compared with the predicted simulation properties.

10

Reconstruction of the Late Bronze Age Foundry Process in Greater Poland: Analyzes and Simulations. Case Study of Hoard from Przybysław

Garbacz-Klempka Aldona, Piękoś Marcin, Perek-Nowak Małgorzata, Kozana Janusz, Żak Paweł, Fijołek Andrzej, Silska Patrycja, Stróżyk Mateusz

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

1125--1136

EN

One of the most interesting categories of artifacts for archaeometallurgical research includes deposits of bronze items, so-called “metallurgists hoards”. They contain, aside of final products, many fragments of raw material and, moreover, metallurgical tools. An important source for the studies on the history of metallurgical technology is hoard from Przybysław, Greater Poland district. Thus, the aim of the work is the identification and interpretation of bronze-working practices and strategies adopted by prehistoric communities of the Late Bronze Age and the Early Iron Age (ca. 600 BC). The examined objects are characterized in terms of their design, structure, and chemical composition. The methods chosen for the studies of artifacts include: metallographic macro- and microscopic observations using optical microscopy (OM) and scanning electron microscopy (SEM), the analysis of chemical composition with the methods of energy dispersive X-ray spectroscopy (EDS), and X-ray fluorescence (ED-XRF). The thermodynamic analysis of the alloys was performed on the basis of the CALPHAD method. The experimental melts allowed to verify the theoretical considerations and to determine the characteristic temperatures of changes. The old casting technology can be analyzed basing on computer modeling and computer simulation methods. Simulations in the MAGMASOFT® software are a good example to illustrate how to fill a mould cavity with a molten bronze for a hoop ornament. It is also an appropriate tool to determine temperature distribution in a mould. The simulations also show the possible disadvantages with this old technology.

11

Influence of Alloying Elements on the Microstructure and Selected High-Temperature Properties of New Cobalt-Based L12-Reinforced Superalloys

Kierat Milena, Moskal Grzegorz, Zieliński Adam, Jung Tymoteusz

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

495--500

EN

The study investigated the primary structure of the new generation of superalloys based on Co-10Al-5Mo-2Nb and Co-20Ni-10Al-5Mo-2Nb cobalt. Research on a group of cobalt-based materials was initiated in 2006 by J. Sato [1]. These materials may replace nickel-based superalloys in the future due to their excellent properties at elevated temperatures relative to nickel-based superalloys. The primary microstructure characterisation of the Co-10Al-5Mo-2Nb and Co-20Ni-10Al-5Mo-2Nb alloy are the basic subject of this article. The Co-10Al-5Mo-2Nb and Co-20Ni-10Al-5Mo-2Nb alloy are tungsten free alloys of a new type with the final microstructure based on the Co-based solid solution L12 phase of the Co3(Al,Mo,Nb) type as a strengthened structural element. The analysed alloys were investigated in an as-cast state after a vacuum casting process applied on graphite moulds. The primary microstructure of the alloys and the chemical constituent of dendritic and interdendritic areas were analysed using light, scanning electron and transmission microscopy. Currently, nickel-strengthened γ’ phase steels are still unrivalled in aerospace applications, however, cobalt based superalloys are a response to their existing limitations, which do not allow maintaining the current rate of development of aircraft engines.

12

Processing of Boron Nitride Nanotubes Reinforced Aluminum Matrix Composite

Nemutlu B., Kahraman O., Demirel K. B., Erkul I., Cicek M., Sahin H., Dizdar K. C., Dispinar D.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 2

5--10

EN

Aluminum and its alloys are one of the most favored metal-based materials for engineering applications that require lightweight materials. On the other hand, composites are getting more preferable for different kinds of applications recently. Boron nitride nanotubes (BNNTs) are one of the excellent reinforcement materials for aluminum and its alloys. To enhance mechanical properties of aluminum, BNNTs can be added with different processes. BNNT reinforced aluminum matrix composites also demonstrate extraordinary radiation shielding properties. This study consists of BNNT reinforced aluminum matrix composite production performed by casting method. Since wetting of BNNT in liquid aluminum is an obstacle for casting, various casting techniques were performed to distribute homogeneously in liquid aluminum. Different methods were investigated in an aim to incorporate BNNT into liquid method as reinforcement. It was found that UTS was increased by 20% and elongation at fracture was increased by 170% when BNNT was preheated at 800°C for 30 minutes.

13

Effect of Zeolite Addition on the Production of a Cast Porous Composite Based on AC-AlSi11 Silumin

Borowiecka-Jamrożek Joanna, Kargul Marcin

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 4

96--101

EN

The paper presents the application of the casting method for the production of porous composites, called syntactic foams, of the casting alloy - solid particles type. This method was used to produce composites based on Al alloys reinforced with particles of clinoptilolite, a natural mineral from the zeolite group. Before the casting process, tests were carried out on the morphology, physicochemical properties and chemical composition of the zeolite, which was obtained from a rock called zeolite tuff, mined in a quarry in Kucin, (VSK PRO-ZEO s.r.o., Slovakia). Observations of the microstructure of the produced composites were also carried out using a scanning electron microscope. Diffractometric tests of zeolite rock as delivered for research and of the produced samples reinforced with zeolite particles were also carried out. Initial studies of the density and porosity of the produced composites were performed. The usefulness of the presented method of composite production was assessed on the basis of the conducted structural tests, with particular emphasis on the particle distribution in the alloy matrix.

14

Microstructure of cast MgBi6X0.5 (X = Ca, Mn, Zn) alloys in peak-aged condition

Gryc Adam, Dybowski Bartłomiej, Jarosz Robert, Kiełbus Andrzej

Journal of Metallic Materials

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2021

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Vol. 73, no. 3

23--28

EN

Cast magnesium alloys are characterised by the lowest density among commercially used structural metals. They are applied mainly in the transportation industry and small, lightweight electronic devices. Due to the low operating temperature of the most widely used alloys from the Mg-Al system, alloys containing rare earth elements with the maximum working temperature reaching 300°C have been developed. However, these alloys are extremely expensive due to the low availability of RE elements. The Mg-Bi system is a promising candidate for the new magnesium-based alloys, as it reveals limited solubility of Bi in Mg enabling precipitation hardening and a high melting point of the Mg3Bi2 phase. The paper presents the results of the analysis of MgBi6 and MgBi6X0.5 (X = Ca, Mn, Zn) alloys’ microstructure in the peak-aged condition. The microstructure of the analysed alloys in the as-cast condition consists of α-Mg solid solution dendrites and Mg3Bi2+α-Mg eutectic compound. Solutionising conducted at 525°C for 8 h, followed by water quenching leads to the dissolution of the intermetallic phases in all of the investigated alloys apart of the MgBi6Ca0.5 alloy. In this case, fine intermetallic phases containing Mg, Bi, and Ca have been found after solutionising. The ageing of the alloys at 200°C results in peak hardness after 120-44 h. The heat treatment leads to the formation of fine strengthening phases within the α-Mg solid solution, characterised by a variety of morphologies -needle, platelet- or lathlike and cuboid. The needle- and platelet- or lathlike phases are found in two sizes -large, with length reaching hundreds of nanometres, and smaller, not exceeding 100 nm. Cuboid particles are found with sizes not higher than 100 nm. The addition of Mn and Zn increases precipitate volume fraction after the heat treatment. Additionally, in the case of the MgBi6Zn0.5 alloy, particles forming an angle of 120° were found, which indicates their presence at the prismatic planes of α-Mg HCP crystal lattice.

PL

Odlewnicze stopy magnezu charakteryzują się najniższą gęstością wśród wszystkich komercyjnie stosowanych stopów konstrukcyjnych. Znajdują zastosowanie głównie w przemyśle transportowym oraz małych, lekkich urządzeniach elektronicznych. Z uwagi na niską temperaturę eksploatacji najpowszechniej stosowanych stopów z układu Mg-Al, opracowano stopy, zawierające pierwiastki ziem rzadkich, znajdujące zastosowanie w temperaturach do 300°C. Jednak stopy z tej grupy są niezwykle drogie, z uwagi na ograniczoną dostępność pierwiastków ziem rzadkich. Obiecującą alternatywę stanowią stopy z układu Mg-Bi, który z uwagi na ograniczoną rozpuszczalność bizmutu w magnezie oraz wysoką temperaturę topnienia fazy Mg3Bi2 umożliwia ich umocnienie na drodze utwardzania wydzieleniowego. W artykule przedstawiono wyniki badań mikrostruktury stopów MgBi6 oraz MgBi6X (X = Ca, Mn, Zn) po starzeniu. Mikrostruktura badanych stopów w stanie lanym składa się z dendrytów roztworu stałego α-Mg oraz mieszaniny eutektycznej Mg3Bi2+α-Mg. Przesycanie, przeprowadzone w temperaturze 525°C przez 8 h z chłodzeniem w wodzie doprowadziło do rozpuszczenia faz międzymetalicznych we wszystkich badanych stopach, z wyjątkiem stopu MgBi6Ca0,5. W jego przypadku po przesycaniu zidentyfikowano w strukturze drobne fazy międzymetaliczne, zawierające Mg, Bi i Ca. Maksymalną twardość stopów po starzeniu w temperaturze 200°C osiągnięto po 120÷144 h. Zastosowana obróbka cieplna doprowadziła do utworzenia się wewnątrz ziaren roztworu stałego α-Mg drobnych faz umacniających o zróżnicowanej morfologii -od iglastej, przez płytkową, po prostopadłościenną. Zaobserwowano dwa typy wydzieleń iglastych i płytkowych -większe, o długości rzędu kilkuset nanometrów oraz mniejsze, nieprzekraczające 100 nm długości. Wydzielenia prostopadłościenne charakteryzowały się rozmiarami, nieprzekraczającymi 100 nm. Dodatek Mn oraz Zn spowodował wzrost udziału objętościowego wydzieleń po obróbce cieplnej. Dodatkowo, w przypadku stopu MgBi6Zn1,5, wydzielenia tworzyły kąt 120°C, co wskazuje na ich obecność na płaszczyznach pryzmatycznych komórki elementarnej α-Mg.

15

Influence of 2% titanium addition on microsctructure and selected high-temperature properties of a novel Co-based superalloy strenghtened with L12 phase

Kierat Milena, Liśkiewicz Maciej

Journal of Metallic Materials

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2021

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Vol. 73, no. 4

11--14

EN

This paper contains selected results of primary microsctructure analysis of a novel superalloy, Co-20Ni-10Al-5Mo-2Nb-2Ti. Research on this class of superalloys was started by J. Sato in 2006, and further expanded by S.K. Makineni in 2015. It is implied that Co-based, W-free superalloys will resolve the issues that the aircraft industry currently faces with Ni-based γ/γ’ superalloys. It is believed that the addition of the Ti alloying element will help with γ’ stabilisation due to high Co3(Mo, Al, Nb) fragmentation. Ti content has to be carefully selected to avoid precipitation of harmful phases, such as Co(Ti, Al).

PL

Artykuł zawiera wyniki badań mikrostrukturalnych nowego nadstopu Co-20Ni-10Al-5Mo-2Nb-2Ti. Badania nad tą klasą superstopów zostały zapoczątkowane w 2006 r. przez J. Sato, a następnie rozwinięte w 2015 r. przez S.K. Makineni. Powszechna jest wiara, że nadstopy oparte na Co i wolne od W rozwiążą problemy z jakimi boryka się obecnie branża lotnicza, w której powszechne jest stosowanie nadstopów Ni γ/γ’. Uważa się, że dodatek Ti do nadstopu spowoduje stabilizację fazy γ’ poprzez silną fragmentację fazy Co3(Mo, Al., Nb). Ilość Ti w badanym stopie została dobrana ze szczególną starannością w celu uniknięcia wydzielania szkodliwych faz takich jak Co(Ti, Al).

16

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.

17

Evaluation of the Cause and Consequences of Defects in Cast Metal-Ceramic Composite Foams

Popielarski P., Sika R., Czarnecka-Komorowska D., Szymański P., Rogalewicz M., Gawdzińska K.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

81--88

EN

In this research, the quality of manufactured cast metal-ceramic foams (manufactured using blowing gas) was tested. The causes responsible for defect formation in the composite foams and their consequences were analyzed using the FMEA (Failure Mode and Effects Analysis) method, which is a useful tool for minimizing losses caused by low product quality. This method involves analytically determining correlations between the cause and consequences of potential product defects, and it takes into account the criticality factor (risk). The FMEA analysis showed that pore breaks were the most "critical defect" (with the highest number of effects on the product, the Risk Priority Number, affecting the quality of the composite foam). The second most critical defect was discontinuities in the foam frame structure. Destruction or damage to the foam structure (although very rare) deprived the composite foam of its primary function, which is to reinforce the product. The third most critical defect was non-uniform foam pore size.

18

Effect of Cooling Rate on the Precipitation Characteristics of Cast Al-Si-Cu Alloy

Okayasu M., Sahara N., Touda M.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 4

55--60

EN

The influence of the cooling rate on the extent of precipitation hardening of cast aluminum alloy (ADC12) was investigated experimentally. This study explored the cooling rate of the solidification of Cu in the α-Al phase to improve the mechanical properties of ADC12 after an aging process (Cu based precipitation hardening). The solid solution of Cu occurred in the α-Al phases during the casting process at cooling rates exceeding 0.03°C/s. This process was replaced with a solid solution process of T6 treatments. The extent of the solid solution varied depending on the cooling rate; with a higher cooling rate, a more extensive solid solution was formed. For the cast ADC12 alloy made at a high cooling rate, high precipitation hardening occurred after low-temperature heating (at 175°C for 20 h), which improved the mechanical properties of the cast Al alloys. However, the low-temperature heating at the higher temperature for a longer time decreased the hardness due to over aging.

19

Design of Proven Technology of Metal Foam and Porous Metal Casting Production

Radkovský F., Merta V., Obzina T.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

125--131

EN

The article describes the design of a proven technology for the production of metal foam and porous metal by the foundry. Porous metal formed by infiltrating liquid metal into a mould cavity appears to be the fastest and most economical method. However, even here we cannot do without the right production parameters. Based on the research, the production process was optimised and subsequently a functional sample of metal foam with an irregular internal structure - a filter - was produced. The copper alloy filter was cast into a gypsum mould using an evaporable model. Furthermore, a functional sample of porous metal with a regular internal structure was produced - a heat exchanger. The aluminium alloy heat exchanger was cast into a green sand mould using preforms. Also, a porous metal casting with a regular internal structure was formed for use as an element in deformation zones. This aluminium alloy casting was made by the Lost Foam method. The aim is therefore to ensure the production of healthy castings, which would find use in the field of filtration of liquid metal or flue gases, in vehicles in the field of shock energy absorption and also in energy as a heat exchanger.

20

Studies on the influence of AlTi5B1 modifier on the structure and properties of AlCuMg alloys

Ściężor Wojciech, Kowal Radosław, Franczak Krystian, Grzebinoga Justyna, Kwaśniewski Paweł, Kiesiewicz Grzegorz

Acta Innovations

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2021

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no. 38

37--48

EN

New materials used in various industries require sufficiently high mechanical properties, fine-grained structure and ease of metal forming while minimizing production costs. For this reason, work is being carried out to develop new groups of alloys that make it possible to increase the strength of the obtained components while reducing their weight, and thus reducing production costs. This article focuses on two aluminium-based alloys with different content of alloying additives: copper and magnesium i.e., AlCu3Mg3 and AlCu4.5Mg6, which were produced by metallurgical synthesis. The as-cast alloys were characterized for their basic physical, mechanical and electrical properties and were subjected to structural analysis. In the next stage, the alloys were modified with 100, 500, 1000 and 2000 ppm of titanium and then their hardness, electrical conductivity and density were tested. Samples were also subjected to microstructural analysis. The obtained results allowed to examine the evolution of the AlCuMg alloy properties depending on the content of alloy additives and the amount of used modifier.