The rapid rise of electric vehicles and the adoption of Giga/Mega/Hyper-casting are transforming automotive manufacturing and dramatically increasing the demand for aluminium components. This shift exposes critical challenges in high-pressure die casting (HPDC), particularly the inability to perform fast, in-line quality assessment and the persistent deterioration of melt quality during handling and mould filling. The current state-of the art understanding is that "hydrogen is not the primary issue; air entrainment and oxide bifilm are". Furthermore, "bifilm generation is dominated by melt handling and mould filling." These defects fundamentally limit mechanical performance, fatigue life, and crashworthiness. Current mitigation strategies-such as gate segmentation and reduced gate speed-offer only partial improvement. The analysis shows that unstable fill-front behaviour in HPDC inherently promotes bifilm formation, whereas semisolid casting can stabilise the flow, suppress fill-front instabilities, and reduce oxide damage. This creates new opportunities for high-integrity structural castings but also introduces challenges related to slurry rheology and segregation. Overall, the work identifies melt handling, fill-front stability, and real-time quality control as the central barriers to producing defect-free aluminium components for next-generation automotive applications.

Ontologies are essential for structuring domain knowledge, improving accessibility, sharing, and reuse. However, traditional ontology construction relies on manual annotation and conventional natural language processing (NLP) techniques, making the process labour-intensive and costly, especially in specialised fields like casting manufacturing. The rise of Large Language Models (LLMs) offers new possibilities for automating knowledge extraction. This study investigates three LLM-based approaches, including pre-trained LLM-driven method, in-context learning (ICL) method and fine-tuning method to extract terms and relations from domain-specific texts using limited data. We compare their performances and use the best-performing method to build a casting ontology that validated by domian expert.

Global aluminium production has been surging in recent years due to its favourable properties, which can be tailored through alloying. To cope with this increasing demand, aluminium production has shifted increasingly towards primary production, as secondary production is restricted by impurity accumulation, particularly iron (Fe). The addition of Fe-bearing intermetallic particle formers, such as manganese (Mn), chromium (Cr), and strontium (Sr), is a potential solution. In contrast to previous studies, which mainly focused on higher-Fe Al-Si alloys, the present work investigates the impact of varying Mn-Cr and Mn-Sr additions on the Fe removal efficiency, defined as the percentage of Fe content in the melt after sedimentation relative to the initial Fe content, the formation of Fe-bearing intermetallic particles and the yield of clean Al following particle sedimentation in low-Fe Al-Si alloys. The experimental work included small-scale melting with 8 kg of Al-11Si-0.5Fe alloys. The study concludes that using Fe-bearing intermetallic particle formers, such as Mn and Cr, is effective for low Fe concentrations in the melt. However, a higher quantity of Mn at constant Cr is necessary for a more efficient reduction of Fe. When comparing Mn-Cr with Mn-Sr additions, Mn-Cr additions improve Fe removal efficiency, whereas Mn-Sr significantly improves the clean aluminium output yield with lower Fe removal efficiency. Further increases in Sr adversely affect particle yield and packing density, with no impact on Fe removal efficiency.

The aluminum casting industry plays a pivotal role in modern manufacturing, contributing to sectors such as automotive, aerospace, and construction. However, the increasing demand for aluminum, coupled with environmental concerns, necessitates a critical evaluation of its raw material sourcing and energy-intensive casting processes. This study explores the dual challenges of raw material criticalities and furnace selection choices in primary and secondary aluminum casting, aiming to chart a pathway toward more sustainable foundry practices. The study is based on the definition of criticality and environmental assessments for a more circular and climate-resilient future. Raw material criticality assessment is assessed through six factors: (1) abundance of elements in the Earth’s crust, (2) sourcing and geopolitical risk, (3) environmental country risk, (4) supply risk, (5) economic importance, and (6) recycling input, while the environmental assessment is made through two major loads: (i) embodied energy, and (ii) carbon footprints. A comparative analysis of common furnace types, including crucible, induction, reverberatory, and stack furnaces, with varying in-house return rates, is conducted to examine the trade-offs in performance from a sustainability perspective. The findings of the proposed work will emphasize the importance of material and process selection in foundries to save the reserves of critical raw materials, implement better closed-loop recycling systems, integrate renewable energy sources, and develop smart furnace operations to minimize environmental footprints. This comprehensive approach is vital for transitioning the foundry industry toward a more circular and climate resilient future.

From introduction: Metal matrix composites (MMCs) are attractive materials due to their unique properties that stem from combining a wide range of matrix materials and reinforcements. The possibility of tailoring the mechanical response, thermophysical properties, chemical and electrical behavior, and wear properties makes MMCs incredibly interesting. The development of such materials has been driven by various applications in different fields, including automotive, aerospace, electrical and electronic applications. The challenge of creating a sustainable society lies in the recyclability of such materials.

Given the fast evolution of these materials and the numerous combination possibilities, the Special Issue “Advances in Metal Matrix Composites: Structure, Properties and Applications” [1] aimed to gather studies on the most recent advances in the field. Articles focusing on material modeling, microstructural characterization, wear testing, and mechanical and thermophysical performance at both room and elevated temperatures are welcome. Articles on the sustainability of MMCs, either by recycling the composite or using recycled matrices and reinforcements, are highly encouraged.

Aluminium-based metal matrix composites (MMCs) are promising materials for automotive brake discs, and aluminium provides an opportunity to use secondary alloys in the production of MMCs. Interest in the sustainability of composites is increasing steadily, and further investigation is needed when secondary aluminium alloys are included as the matrix. The drawback is that secondary aluminium alloys usually include several impurities and oxides that can harm the mechanical and thermophysical properties. Given the promising results of the preliminary studies, the present work focuses on the characterization of Al-Si-based MMCs reinforced with 20 wt. % of SiC particles. The brake discs are produced by squeeze casting using 0 %, 50 %, 70 %, and 100 % secondary AlSi9Mg alloy for the matrix.

The critical material properties for brake discs are good thermal conductivity, a suitable mechanical response at high temperatures, and a coefficient of friction that guarantees an acceptable braking performance. The microstructure of the MMC produced with the secondary alloy was comparable to that of the reference composite (0% recycled alloy), indicating good incorporation of SiC particles inthe melt. The intermetallic phases present are linked to magnesium and iron, with Chinese script and lamellar morphologies, especially in MMCs containing recycled alloys. The presence of these phases had a limited effect on the thermal conductivities of the composites produced with secondary alloys. Similarly, the compression strength up to 470 °C is in line with that of the reference composites, indicating that the microstructural features related to the secondary alloy have a limited impact on the mechanical performance. The evolution of the microstructure with different strain rates and temperatures was investigated by SEM, EDS, and EBSD to describe the role of different microstructural features. The results of the present study confirm that these composite materials provide good mechanical performance and suitable thermophysical properties for automotive brake discs combined with a lightweight solution. The main challenge lies in the recyclability of the material at the end-of-life of the brake disc, which will be the focus of our future research.

To enhance the sustainability of aluminum castings, the use of recycled alloys is increasing due to their lower energy demand and reduced carbon footprint. At the same time, semisolid metal (SSM) rheocasting is emerging as a viable alternative to High Pressure Die Casting (HPDC), enabling the processing of low-silicon aluminum alloys. This reduces the need for critical raw materials, such as primary silicon, and allows casting at lower temperatures, further improving efficiency. However, contaminants typically present in recycled alloys, particularly iron, influence castability, defect formation, and mechanical performance, requiring further investigation. This study analyzes the tensile properties and cracking mechanisms of semi-solid cast AlSi7Mg alloys with varying iron content: primary (Fe = 0.08%), recycled (Fe = 0.19%), and recycled high iron (Fe = 0.42%), produced via the Rheometal™ method. Tensile testing was performed on as-cast and T6 samples. Statistical analysis was applied to evaluate variability and statistical significance of the results. The results show that recycled alloys have a higher defect density at an increased iron content, leading to lower elongation, reduced strength, and greater variability than in the primary alloy (recycled alloy Fe=0.19%: as-cast Rp0.2=113±8 MPa, Rm=208±15 MPa, ef=4.13±0.95 %; T6 Rp0.2=240±17 MPa, Rm=279±27 MPa, ef=1.40±0.20 %). The T6 treatment improved strength but reduced ductility due to defect enlargement and surface blistering caused by solubilization step, particularly pronounced in the recycled alloy with high-iron content. Scanning electron microscopy (SEM) fractography indicated that oxide films act as nucleation sites for β-Al5FeSi intermetallics, which promote shrinkage defects and thereby limit elongation. 

In this study, the in situ 4 wt.% TiB2(p)/Al-Cu composite was prepared through a mixed salt reaction method. To evaluate its formability, hot isothermal compression tests were performed using a Gleeble−3500 system in a temperature range of 480-510 °C and a strain rate range of 0.1-10 s−1. A constitutive model of the composites with strain compensation was established, and the true stress–strain curves revealed that the composite exhibited favorable formability at 510 °C. Additionally, single-pass equal channel angular pressing (ECAP) processes were conducted at room temperature and 510 °C to investigate the microstructure evolution of the composite. The distribution of TiB2 particles was found to be influenced by deformation temperature, while the microstructural characteristics of the aluminum matrix were minimally affected. Furthermore, a comparison between the as-cast composite and the deformed composites revealed the presence of different preferred orientations in the two conditions, and the corresponding paths of texture evolution were estimated accordingly. Remarkably, after undergoing single-pass ECAP, the Schmid factors of composites remained nearly unchanged, demonstrating that deformed composites were still appropriate for processing and as such demonstrating a potential route also for formability assessment.

Over the past decades, demand for high-purity aluminium (Al) has increased in many sectors, like aerospace and automotive sectors, since it combines a high level of purity with the flexibility of controlled alloying, which allows for tailored enhancements of material properties. To accommodate the rising demand, primary Al production has significantly increased since the refining of secondary Al is constrained by high impurity levels, especially iron (Fe). A way to mitigate this problem is to add Fe-bearing intermetallic particle formers, like manganese (Mn). This paper investigates the influence of different Mn additions for low-Fe composition aluminium melts at a cooling rate of 3 °C/min, as the primary Fe-rich phases may differ and cannot be extrapolated. More specifically, the impact of filters, the Fe removal efficiency for different Mn additions, and the Fe-bearing intermetallic particles’ Fe removal potential. Fe removal potential was evaluated by combining intermetallic particle area fraction with their average Fe content. This was done by running Thermo-Calc equilibrium calculations to guide the planning of the experimental work. Then, running small-scale experiments with 8 kg of Al-11Si-0.5Fe alloy. The study concludes that the Fe-bearing intermetallic parties sedimented at the bottom of the furnace since the composition of the filtered and unfiltered samples from the top part of the melt was similar. Additionally, larger amounts of Mn are required to improve the Fe removal efficiency for low-Fe concentration Al-Si cast alloys since it improves the Fe removal potential and increases the amount of Fe-bearing intermetallic particles in the melt.