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Keywords = secondary aluminium

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20 pages, 1280 KiB  
Article
Optimizing the Composition of Geopolymer Composites Incorporating Secondary Aluminium Industry By-Products Using Mathematical Modelling
by Artem Sharko, Van Su Le, Oleksandr Sharko, Dmitry Stepanchikov, Pavel Srb, Michal Petrů, Petr Louda, Petro Movchan and Katarzyna Ewa Łoś
Materials 2025, 18(12), 2840; https://doi.org/10.3390/ma18122840 - 16 Jun 2025
Viewed by 310
Abstract
Geopolymer composite materials are a viable alternative to conventional construction materials. The research problem of geopolymer composites revolves around the imperative to comprehensively address their synthesis, structural performance, and environmental impact. The derived mathematical model facilitates precisely determining the optimal proportions of two [...] Read more.
Geopolymer composite materials are a viable alternative to conventional construction materials. The research problem of geopolymer composites revolves around the imperative to comprehensively address their synthesis, structural performance, and environmental impact. The derived mathematical model facilitates precisely determining the optimal proportions of two crucial constituents in the geopolymer matrix: silica sand and secondary aluminum by-product. A mathematical model for optimizing the composition of geopolymer composites has been developed based on the integrated use of Markov chains, criterion methods, and an orthogonally compositional plan. The optimal composition of the geopolymer matrix is determined and predicted using a mathematical model. Specifically, the recommended content mixing ratio is as follows: metakaolin at 1000 g, activator at 900 g, silica fume at 1052.826 g, carbon fibre at 10 g, and secondary aluminum by-product at 62.493 g. This study analyzes the influence of different secondary aluminum industry by-products on the geopolymerization process and assesses the mechanical, thermal, and environmental properties of the resulting composites to establish a comprehensive understanding of their structural viability. Full article
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20 pages, 5068 KiB  
Article
Energy-Absorbing Countermeasures for Subway-to-Pedestrian Collisions: A Combined Experimental and Multibody Modelling Approach
by Daniel Hall, Logan Zentz, Patrick Lynch and Ciaran Simms
Appl. Sci. 2025, 15(11), 6219; https://doi.org/10.3390/app15116219 - 31 May 2025
Viewed by 417
Abstract
Epidemiological analysis has revealed key insights into the frequency, severity, and circumstances surrounding subway-to-pedestrian incidents; however, there remains a lack of available impact test data specific to this impact type that can be used in modelling and countermeasure design studies. To address this [...] Read more.
Epidemiological analysis has revealed key insights into the frequency, severity, and circumstances surrounding subway-to-pedestrian incidents; however, there remains a lack of available impact test data specific to this impact type that can be used in modelling and countermeasure design studies. To address this gap, nine controlled impact tests were conducted using a cylindrical headform to derive force–penetration relationships for foam, as well as foam encased in 1 mm aluminium or 3 mm ABS shells. These relationships were validated in MADYMO multibody simulations. Building on a previous multibody computational study of subway-to-pedestrian collisions this research evaluates three passive countermeasure designs using a reduced simulation test matrix: three impact velocities (8, 10, and 12 m/s) and a trough depth of 0.75 m. In subway collisions, due to the essential rigidity of a subway front relative to a pedestrian, it is the pedestrian stiffness characteristics that primarily dictate the contact dynamics, as opposed to a combined effective stiffness. However, the introduction of energy-absorbing countermeasures alters this interaction. Results indicate that modular energy-absorbing panels attached to the train front significantly reduced the Head Injury Criterion (HIC) (by 90%) in the primary impact and pedestrian-to-wheel contact risk (by 58%), with greater effectiveness when a larger frontal area was covered. However, reducing primary impact severity alone did not substantially lower total fatal injury risk. A rail-guard design, used in combination with frontal panels, reduced secondary impact severity and led to the largest overall reduction in fatal injuries. This improvement came with an expected increase in hospitalisation-level outcomes, such as limb trauma, reflecting a shift from fatal to survivable injuries. These findings demonstrate that meaningful reductions in fatalities are achievable, even with just 0.5 m of available space on the train front. While further development is needed, this study supports the conclusion that subway-to-pedestrian fatalities are preventable. Full article
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14 pages, 5677 KiB  
Article
Solidification Window in Al-Based Casting Alloys
by Simone Ferraro, Mauro Palumbo, Marcello Baricco and Alberto Castellero
Metals 2025, 15(5), 489; https://doi.org/10.3390/met15050489 - 26 Apr 2025
Viewed by 522
Abstract
Semi-solid processes of aluminium alloys, characterised by the coexistence of solid and liquid phases, offer advantages in terms of mechanical properties and fatigue resistance, thanks to the more globular microstructure. Thermodynamic models can be used to analyse the solidification behaviour and to predict [...] Read more.
Semi-solid processes of aluminium alloys, characterised by the coexistence of solid and liquid phases, offer advantages in terms of mechanical properties and fatigue resistance, thanks to the more globular microstructure. Thermodynamic models can be used to analyse the solidification behaviour and to predict the solidification window, ΔT. The CALPHAD method enables the calculation of the phases formed during solidification and the optimisation of alloy composition to meet specific industrial requirements. This study aims to assess how thermodynamic properties in both liquid and solid phases affect the ΔT. Initially, the influence of thermodynamic properties of pure components and interaction parameters was analysed in simplified regular binary systems. To compare these findings with real industrial systems, Al-based alloys were examined. Using available databases, the ΔT was estimated via the CALPHAD method adding alloying elements commonly found in secondary Al-alloys. Finally, the same minority alloying elements were added to Al-Si 8 and 11 wt.% alloys, and the corresponding ΔT were calculated. Cr, Fe, Mg, Mn, and Ti increase the ΔT, while Cu, Ni, and Zn decrease it. The obtained results may serve as a valuable tool for interpreting phenomenological observations and understanding the role of minority elements in the semi-solid processing of secondary Al-Si casting alloys. Full article
(This article belongs to the Special Issue Solidification and Phase Transformation of Light Alloys)
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13 pages, 4638 KiB  
Article
Migration and Conversion of Al Element in the Hydrometallurgical Preparation of Al2O3 from Secondary Aluminium Dross
by Kepeng Huang, Changjiang Zheng, Qingda Li, Xinyang Qiu and Xuemei Yi
Processes 2025, 13(5), 1281; https://doi.org/10.3390/pr13051281 - 23 Apr 2025
Viewed by 451
Abstract
The amount of secondary aluminium dross in China exceeds one million tons annually, posing environmental and disposal challenges. This study explores acid leaching as an alternative to conventional alkali methods for recovering Al from secondary aluminium dross to produce Al2O3 [...] Read more.
The amount of secondary aluminium dross in China exceeds one million tons annually, posing environmental and disposal challenges. This study explores acid leaching as an alternative to conventional alkali methods for recovering Al from secondary aluminium dross to produce Al2O3. Research has focused on optimizing leaching conditions. Under optimized H2SO4 leaching conditions, an Al3+ leaching ratio of 86.5% is achieved. By maintaining a pH below 9 during hydrolytic precipitation and multiple washes, the leaching efficiency of Al from Al(OH)3 reached 95.97%. The original dross, which is primarily composed of Al, Al2O3, and AlN, undergoes a transformation where AlN becomes Al(OH)3 during washing. Thermal decomposition then yields Al2O3. The overall recovery of Al reaches 83.11%. Full article
(This article belongs to the Special Issue Recent Trends in Extractive Metallurgy)
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23 pages, 10327 KiB  
Article
Excessive Fe Contamination in Secondary Al Alloys: Microstructure, Porosity, and Corrosion Behaviour
by Helder Nunes, Rui Madureira, Manuel F. Vieira, Ana Reis and Omid Emadinia
Metals 2025, 15(4), 451; https://doi.org/10.3390/met15040451 - 17 Apr 2025
Viewed by 623
Abstract
The characterisation of aluminium casting alloys with iron concentrations exceeding current standards is essential, as upcycling has recently become a significant concern in achieving a more circular economy. Secondary aluminium casting alloys often exhibit insufficient mechanical properties for load-bearing automotive applications due to [...] Read more.
The characterisation of aluminium casting alloys with iron concentrations exceeding current standards is essential, as upcycling has recently become a significant concern in achieving a more circular economy. Secondary aluminium casting alloys often exhibit insufficient mechanical properties for load-bearing automotive applications due to contamination with iron, mainly due to alloy mixing or remnants from end-of-life products during downcycling. This trend is anticipated to soon lead to a surplus of scrap. This study aims to fully understand the microstructural changes, intermetallic phase morphologies, and defect formation in AlSiMg alloy highly contaminated with Fe that exists in Al scraps and is detrimental for upcycling purposes. The investigation examined the AlSi7Mg0.3 alloy with Fe concentrations ranging from 0.1 to 3.8 wt.% Fe, employing thermodynamic simulations, hardness testing, quantitative image analysis, and corrosion tests. Among these alloys, the AlSi7Mg0.3-3.8Fe, containing the highest level of contamination, exhibited the most complex microstructure. This microstructure is characterised by the presence of two distinct Fe-rich intermetallic phases with diverse shapes and sizes: petal-like α′-Al8Fe2Si, long and thick β-Al4.5FeSi plaques, and very thin β-Al4.5FeSi needles. The significant growth in these phases with higher Fe concentration resulted in increases in hardness (15 HBW), porosity (1.39%), and corrosion rate (approximately 12 times). Full article
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18 pages, 5899 KiB  
Article
Development of Heat Treatments for Structural Parts in Aluminium Alloys Produced by High-Pressure Die Casting (HPDC)
by Rui Gomes, Gonçalo Soares, Rui Madureira, Rui Pedro Silva, José Silva, Rui Neto, Ana Reis and Cristina Fernandes
Metals 2024, 14(9), 1059; https://doi.org/10.3390/met14091059 - 16 Sep 2024
Cited by 5 | Viewed by 1590
Abstract
In this work, we intended to study the effect of heat treatments (T5 and flash T6) on blistering, mechanical properties and microstructure for different parts produced by vacuum-assisted HPDC. These parts were produced with primary and secondary aluminium alloys (AlSi10MnMg alloy and AlSi10Mg(Fe) [...] Read more.
In this work, we intended to study the effect of heat treatments (T5 and flash T6) on blistering, mechanical properties and microstructure for different parts produced by vacuum-assisted HPDC. These parts were produced with primary and secondary aluminium alloys (AlSi10MnMg alloy and AlSi10Mg(Fe) alloy, respectively). The parts presented blisters for all combinations of temperature (between 360 °C and 520 °C) and stage times (15 and 30 min) of solution heat treatments. However, when subjected to the T5 heat treatment, blisters were no longer visible. With this heat treatment, there was an increase in yield strength of 64% for both aluminium alloys and an increase in UTS of 31% in AlSi10Mg(Fe) alloy and of 24% in AlSi10MnMg alloy, when compared to the mechanical properties in the as-cast state. However, there was a decrease in ductility. The AlSi10Mg(Fe) alloy presented a lot of contaminations (especially iron), which impaired the mechanical properties compared to the primary aluminium alloy, AlSi10MnMg. Full article
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16 pages, 7182 KiB  
Article
Waste Symbiosis through the Synthesis of Highly Crystalline LTA and SOD Zeolites
by Magali Teresinha Ritter, Isabel Padilla, María Ángeles Lobo-Recio, Maximina Romero and Aurora López-Delgado
Materials 2024, 17(17), 4310; https://doi.org/10.3390/ma17174310 - 30 Aug 2024
Viewed by 1480
Abstract
In recent years, the demand for natural and synthetic zeolites has surged due to their distinctive properties and myriad industrial applications. This research aims to synthesise crystalline zeolites by co-recycling two industrial wastes: salt slag (SS) and rice husk ash (RHA). Salt slag, [...] Read more.
In recent years, the demand for natural and synthetic zeolites has surged due to their distinctive properties and myriad industrial applications. This research aims to synthesise crystalline zeolites by co-recycling two industrial wastes: salt slag (SS) and rice husk ash (RHA). Salt slag, a problematic by-product of secondary aluminium smelting, is classified as hazardous waste due to its reactive and leachable nature, though it is rich in aluminium. Conversely, RHA, an abundant and cost-effective by-product of the agro-food sector, boasts a high silicon content. These wastes were utilised as aluminium and silicon sources for synthesising various zeolites. This study examined the effects of temperature, ageing time, and sodium concentration on the formation of different zeolite phases and their crystallinity. Results indicated that increased Na+ concentration favoured sodalite (SOD) zeolite formation, whereas Linde type–A (LTA) zeolite formation was promoted at higher temperatures and extended ageing times. The formation range of the different zeolites was defined and supported by crystallographic, microstructural, and morphological analyses. Additionally, the thermal behaviour of the zeolites was investigated. This work underscores the potential to transform industrial waste, including hazardous materials like salt slag, into sustainable, high-value materials, fostering efficient waste co-recycling and promoting clean, sustainable industrial production through cross-sectoral industrial symbiosis. Full article
(This article belongs to the Special Issue Sustainable Zeolites: Advances in Synthesis and Applications)
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15 pages, 2964 KiB  
Article
Towards Safe Diatomite Sludge Management: Lead Immobilisation via Geopolymerisation
by Haozhe Guo, Zhihao Huang, Baifa Zhang, Ting Yu, Thammaros Pantongsuk and Peng Yuan
Minerals 2024, 14(8), 763; https://doi.org/10.3390/min14080763 - 27 Jul 2024
Viewed by 1374
Abstract
Diatomite, a natural adsorbent rich in active silica, serves as a valuable precursor for geopolymer synthesis. The safe disposal of diatomite as a failed lead (Pb(II)) adsorbent is critical to prevent secondary contamination. This study investigated the immobilisation efficiency of geopolymerisation for Pb(II)-rich [...] Read more.
Diatomite, a natural adsorbent rich in active silica, serves as a valuable precursor for geopolymer synthesis. The safe disposal of diatomite as a failed lead (Pb(II)) adsorbent is critical to prevent secondary contamination. This study investigated the immobilisation efficiency of geopolymerisation for Pb(II)-rich diatomite sludge. Low-grade diatomite with high ignition loss was utilised in the synthesis of alkali-activated geopolymers. It was demonstrated that the geopolymers achieved a compressive strength of 28.3 MPa with a 50% replacement rate of metakaolin by diatomite sludge, which was not a compromise in strength compared to that of the geopolymer with no Pb(II) (26.2 MPa). The leaching behaviour of Pb(II) was evaluated using water and acetic acid, yielding concentrations below 3 mg/L and immobilisation efficiencies of 95% in both scenarios. Analytical techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) elucidated the mineral composition and chemical environment of the geopolymers. These analyses revealed that Pb(II) migrated from diatomite pores, potentially forming soluble hydroxides under sufficient hydroxide, which then participated in condensation with silicon and aluminium monomers, effectively immobilising Pb(II) within amorphous aluminosilicate gels. Furthermore, the formation of the amorphous gels within diatomite pores hindered Pb(II) leaching, encapsulating Pb(II) effectively. This study presents a novel approach to immobilising heavy metals within building materials, enhancing mineral resource utilisation efficiency while addressing environmental contamination concerns. Full article
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19 pages, 16728 KiB  
Article
Influence of Copper Addition on the Mechanical Properties and Corrosion Resistance of Self-Hardening Secondary Aluminium Alloy AlZn10Si8Mg
by Martin Mikolajčík, Lenka Kuchariková, Eva Tillová, Jon Mikel Sanchez, Zuzana Šurdová and Mária Chalupová
Metals 2024, 14(7), 776; https://doi.org/10.3390/met14070776 - 30 Jun 2024
Cited by 4 | Viewed by 2057
Abstract
Aluminium alloys have a wide range of applications, mainly due to their advantageous strength-to-weight ratio, denoted as specific strength and corrosion resistance. In recent decades, there has been a notable surge in the usage of recycled alloys, attributed to their reduced production costs [...] Read more.
Aluminium alloys have a wide range of applications, mainly due to their advantageous strength-to-weight ratio, denoted as specific strength and corrosion resistance. In recent decades, there has been a notable surge in the usage of recycled alloys, attributed to their reduced production costs and emissions. One of the conditions for secondary production is the optimal sorting of used scrap. Once the aluminium scrap has been melted, it is tough to reduce the content of the various additives. Copper is the primary alloying element in some aluminium alloys, which leads to an increased amount of copper in the aluminium scrap. Therefore, it is important to investigate its effect on the properties of aluminium alloys in which it is not commonly present. For this reason, this paper is concerned with the influence of copper on the microstructure and properties of the secondary aluminium alloy AlZn10Si8Mg. Specifically, it compares two melts of self-hardening AlZn10Si8Mg alloys differing in copper content (0.019% and 1.72%). A complex quantitative and metallographic analysis by optical and electron microscopy has been performed. Mechanical properties were investigated by tensile test, Brinell hardness, and Vickers microhardness measurements. The corrosion resistance of the individual melts was verified by the Audi test. Full article
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20 pages, 35119 KiB  
Article
Effect of Rotational Shear and Heat Input on the Microstructure and Mechanical Properties of Large-Diameter 6061 Aluminium Alloy Additive Friction Stir Deposition
by Xiaohu Zhu, Rui Wang, Lin Wang, Mengmeng Liu and Songmo Li
Crystals 2024, 14(7), 581; https://doi.org/10.3390/cryst14070581 - 25 Jun 2024
Cited by 5 | Viewed by 1182
Abstract
Additive friction stir deposition (AFSD), in which molten metal materials are formed into free-form stacked structural parts according to the path design, may have a wide range of applications in high-efficiency mass production. In this study, experiments were conducted for the rotational speed [...] Read more.
Additive friction stir deposition (AFSD), in which molten metal materials are formed into free-form stacked structural parts according to the path design, may have a wide range of applications in high-efficiency mass production. In this study, experiments were conducted for the rotational speed in the AFSD parameters of 6061 aluminium alloy bars to investigate the effects of different rotational shear conditions and heat inputs on the properties of the deposited layer for diameter bars based on the analysis of the micro-morphology, micro-tissue composition, and mechanical properties. The width and thickness of each layer were constant, approximately 40 mm wide and 2.5 mm thick. The particle undulations on the surface of the deposited layer were positively correlated with the AFSD rotational speed. Continuous dynamic recrystallisation in the AFSD process can achieve more than 90% grain refinement. When the rotational speed increases, it causes localised significant orientation and secondary deformation within the recrystallised grains. The ultimate tensile strength of the deposited layer was positively correlated with the rotational speed, reaching a maximum of 211 MPa, and the elongation was negatively correlated with the rotational speed, with a maximum material elongation of 37%. The cross-section hardness of the deposited layer was negatively correlated with the number of thermal cycles, with the lowest hardness being about 45% of the base material and the highest hardness being about 80% of the base material. Full article
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16 pages, 5919 KiB  
Article
Optimizing Wet Hydrolysis for Nitrogen Removal and Alumina Recovery from Secondary Aluminium Dross (SAD)
by Qiao Jiang and Bin Lee
Sustainability 2024, 16(13), 5312; https://doi.org/10.3390/su16135312 - 21 Jun 2024
Cited by 1 | Viewed by 1982
Abstract
Secondary aluminum dross is a solid waste generated after removing aluminum from industrial aluminum slag (primary aluminum dross), which is included in the European Hazardous Waste List because of harmful substances such as aluminum nitride. More and more SAD is being directly disposed [...] Read more.
Secondary aluminum dross is a solid waste generated after removing aluminum from industrial aluminum slag (primary aluminum dross), which is included in the European Hazardous Waste List because of harmful substances such as aluminum nitride. More and more SAD is being directly disposed of in landfills, which will not only harm the ecological environment and human health, but also cause resources. Under the background of green and low-carbon circular economy, nitrogen removal and resource recycling of SAD are very important environmental pollution, resource and the economic benefits of the aluminum industry. In this study, a new method was introduced to explore the interaction between various factors in the denitrification process by using the response surface method, and the optimal denitrification process conditions were predicted and determined by a regression equation that is, the denitrification rate of SAD was 99.98% at the reaction time of 263 min, reaction temperature of 95 ℃ and concentration of 6.5 wt.%. Furthermore, the content of Al2O3 in SAD was successfully elevated to 98.43% through the reaction carried out in a 10 wt.% NaOH solution system at the controlled temperature of 90 °C for 5 h. It was summarized that the wet treatment methodology can efficiently eliminate aluminum nitride (AlN) from SAD and heighten the Al2O3 grade to meet metallurgical standards. This research is expected to eliminate the adverse impact of SAD on the environment and its safety risks, and provide an innovative method for the sustainable resource utilization of SAD. Full article
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21 pages, 29925 KiB  
Article
The Impact of Multiple Thermal Cycles Using CMT® on Microstructure Evolution in WAAM of Thin Walls Made of AlMg5
by Vinicius Lemes Jorge, Felipe Ribeiro Teixeira, Sten Wessman, Americo Scotti and Sergio Luiz Henke
Metals 2024, 14(6), 717; https://doi.org/10.3390/met14060717 - 17 Jun 2024
Cited by 5 | Viewed by 1727
Abstract
Wire Arc Additive Manufacturing (WAAM) of thin walls is an adequate technology for producing functional components made with aluminium alloys. The AlMg5 family is one of the most applicable alloys for WAAM. However, WAAM differs from traditional fabrication routes by imposing multiple thermal [...] Read more.
Wire Arc Additive Manufacturing (WAAM) of thin walls is an adequate technology for producing functional components made with aluminium alloys. The AlMg5 family is one of the most applicable alloys for WAAM. However, WAAM differs from traditional fabrication routes by imposing multiple thermal cycles on the material, leading the alloy to undergo cyclic thermal treatments. Depending on the heat source used, thermal fluctuation can also impact the microstructure of the builds and, consequently, the mechanical properties. No known publications discuss the effects of these two WAAM characteristics on the built microstructure. To study the influence of multiple thermal cycles and heat source-related thermal fluctuations, a thin wall was built using CMT-WAAM on a laboratory scale. Cross-sections of the wall were metallographically analysed, at the centre of a layer that was re-treated, and a region at the transition between two layers. The focus was the solidification modes and solubilisation and precipitations of secondary phases. Samples from the wall were post-heat treated in-furnace with different soaking temperatures and cooling, to support the results. Using numerical simulations, the progressive thermal cycles acting on the HAZ of one layer were simplified by a temperature sequence with a range of peak temperatures. The results showed that different zones are formed along the layers, either as a result of the imposed thermal cycling or the solidification mode resulting from CMT-WAAM deposition. In the zones, a band composed of coarse dendrites and an interdendritic phase and another band formed by alternating sizes of cells coexisted with the fusion and heat-affected zones. The numerical simulation revealed that the thermal cycling did not significantly promote the precipitation of second-phase particles. Full article
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22 pages, 13155 KiB  
Article
Analysis of Inclusions and Impurities Present in Typical HPDC, Stamping and Extrusion Alloys Produced with Different Scrap Levels
by Manel da Silva, Jaume Pujante, Joanna Hrabia-Wiśnios, Bogusław Augustyn, Dawid Kapinos, Mateusz Węgrzyn and Sonia Boczkal
Metals 2024, 14(6), 626; https://doi.org/10.3390/met14060626 - 25 May 2024
Cited by 4 | Viewed by 2005
Abstract
The European Green Deal poses a two-pronged challenge for the automotive industry: migrating to solutions based on light structures, requiring lightweight concepts and light materials, while at the same time avoiding dependence on the importation of these advanced materials. Aluminium alloys are lightweight [...] Read more.
The European Green Deal poses a two-pronged challenge for the automotive industry: migrating to solutions based on light structures, requiring lightweight concepts and light materials, while at the same time avoiding dependence on the importation of these advanced materials. Aluminium alloys are lightweight and cost-effective materials that can successfully meet the requirements of many structural applications; however, their production requires bauxite and other Critical Raw Materials (CRMs), such as Si and Mg. Aluminium alloys are fully recyclable, but scrap is usually contaminated and its use is related to an increment of impurities, tramp elements and undesired inclusions. Traditionally, the use of secondary alloys has been restricted to low-performance applications. The present work analyses the effect that the use of scrap has on the quantity of inclusions present in the alloy and on other properties relevant for material processing. This study was carried out using common alloys associated with three of the most common aluminium processes used in the car manufacturing industry: high-pressure die casting (HPDC) (AB-43500), extrusion (6063) and sheet metal forming (5754 and 6181). The reference alloys were mixed with different levels of scrap (0, 20, 40, 60, 80 and 100%), with an aim to keep the chemical composition as unaffected as possible. The inclusion level of the alloy was characterized using the Prefil Footprinter® test. In addition, the obtained materials, after being cast in an open mould, were subjected to metallographic characterization. Relevant properties were measured to assess the processability of the alloys for the corresponding transforming process using the flowability test for the HPDC alloy and high-temperature compression for the extrusion alloys. The results obtained suggest that the number of inclusions present in the melt highly increase with the amount of scrap used to produce the alloy. These inclusions are also related to a significant loss of flowability, but do not have a noticeable impact on microstructure. Full article
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2 pages, 130 KiB  
Abstract
Phenolics and Flavonoid Content in Selected Seeds from the Serbian Market
by Margarita Dodevska, Nevena Ivanovic, Jelena Kukic-Markovic and Verica Jovanovic
Proceedings 2023, 91(1), 374; https://doi.org/10.3390/proceedings2023091374 - 27 Feb 2024
Viewed by 873
Abstract
Objectives: Edible seeds are usually consumed as common food ingredients. They are considered to have a rich nutrient profile, containing different macro and micronutrients, as well as some biologically active compounds with positive health effects, such as different phenolics. The aim of this [...] Read more.
Objectives: Edible seeds are usually consumed as common food ingredients. They are considered to have a rich nutrient profile, containing different macro and micronutrients, as well as some biologically active compounds with positive health effects, such as different phenolics. The aim of this work was to determine total phenolics (TPC) and total flavonoid content (TFC) in selected commercial seeds samples from the Serbian market. Methods: Samples of nine seeds were investigated (sesame and black sesame, raw and roasted sunflower, raw and roasted pumpkin, hemp, chia and linseed). The samples of native seeds and those defatted using dichloromethane (maceration and Soxhlet extraction) were extracted with 80% methanol. Obtained hydro-methanol extracts were dried and further analysed using spectrophotometric methods: TPC was determined using Folin–Ciocalteu (FC) reagent and expressed as gallic acid equivalents (GAE), while TFC was measured based on the reaction between flavonoids and aluminium chloride and expressed as catechin equivalents (KE). Results: In general, hydro-methanol extracts of seed samples defatted using Soxhlet extraction had the highest TPC and TFC contents. TPC values ranged from 9.47 g GAE/mg (raw pumpkin seed) to over 170 g GAE/mg (raw sunflower seeds). As for TFC, the highest amount was measured in extracts of defatted raw sunflower seeds (over 150 g KE/mg), while roasted pumpkin and hemp seeds’ extracts were practically devoid of flavonoids. Conclusion: Our results confirmed the fact that certain defatted seeds, which are usually considered as waste products in oil production, could be considered as valuable sources of certain secondary plant metabolites, implicating further investigations on their composition and potential in the development of functional foods. Full article
(This article belongs to the Proceedings of The 14th European Nutrition Conference FENS 2023)
6 pages, 2691 KiB  
Proceeding Paper
Quality Assessment of Aluminium Castings Using Computed Tomography
by Martin Pinta, Ladislav Socha, Karel Gryc, Jana Sviželová and Kamil Koza
Eng. Proc. 2024, 64(1), 6; https://doi.org/10.3390/engproc2024064006 - 21 Feb 2024
Cited by 1 | Viewed by 1069
Abstract
The article deals with the use of computed tomography, an advanced method for evaluating the quality of aluminium castings. Casting quality is a key factor in ensuring safety and reliability in industrial applications. Computed tomography is a comprehensive method allowing a three-dimensional, high-resolution [...] Read more.
The article deals with the use of computed tomography, an advanced method for evaluating the quality of aluminium castings. Casting quality is a key factor in ensuring safety and reliability in industrial applications. Computed tomography is a comprehensive method allowing a three-dimensional, high-resolution view of the internal structure of materials. The main focus of this paper is the study of BRACKET REAR aluminium castings, manufactured in two-piece moulds using a high-pressure die-casting technology. In this paper, four castings have been analysed which are produced in one cycle. The focus is on the problem of porosity and open stagnation in the castings. A numerical simulation has also been used to illustrate the occurrence of porosity, which can be used to determine both the occurrence of porosity and the occurrence of unfilled volume. The experimental part of the paper describes the methods used to evaluate the BRACKET REAR castings. The numerical simulation was performed in ProCAST 18.0 to determine the occurrence of porosity in the castings under study. The evaluation of computed tomography was performed in myVGL 3.0 2023 software to analyse the internal defects in the castings. The evaluation focused on assessing internal defects and their subsequent effect on the functionality of the final casting. Full article
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