Cast Aluminum Alloy Research Articles

Solid-state friction rolling repair technology for various forms of defects through multi-layer multi-pass deposition

The current Friction Stir Welding (FSW) based solid-state defect repairing method is an ideal repair technology for high-strength aluminum alloy. However, due to the limitation of pin length and the existence of shoulder, the stirring pin cannot penetrate deep into the root of defects and is difficult to extend in the width direction, which poses great challenges for components with large defects, such as one-dimensional, two-dimensional and volume defects. To overcome these limitations, this study successfully achieved effective repair of various forms of defects using the solid-state Friction Rolling Repair (FRR) technology through multi-layer multi-bead deposition. The microstructure and mechanical properties of the repaired ZL114A cast aluminum alloy joints were investigated. The results demonstrate well-bonded repaired boundaries, significant grain refinement at the junction between the repaired area and boundary, and ultimate tensile strength exceeding 80 % of base material strength. The average grain size of the repaired area can reach a minimum of 2.82 μm. The grain refinement degree of the side joint of the surface defect repair sample is higher than that of the bottom joint, and the corner joint of the bottom surface shows the highest proportion of recrystallized grains. Fracture locations were consistently within the interior of the repair zone in tensile specimens, indicating superior properties at side joints compared to those within the interior. The research proves that FRR has the ability to repair a variety of typical defects, including one-dimensional, two-dimensional and volume defects, in the process of processing and service, which lays a foundation for the industrial application of FRR.

Co-, Ni- and Fe-rich grain-boundary phases enhance creep resistance in θ′-strengthened Al-Cu alloys

Microstructural evolution and creep response were investigated in the cast Al-5.0Cu-0.3Mn-0.2Zr (wt.%) alloy with and without addition of slow-diffusing, intermetallic-forming elements Fe, Ni, or Co. Baseline Al-5.0Cu-0.3Mn-0.2Zr alloy exhibits high creep resistance at 300 °C, up to ∼75 MPa, which is attributed to high-aspect-ratio, intragranular θ′-Al2Cu precipitates that effectively suppress dislocation climb. However, θ′-Al2Cu precipitate-free zones form along grain boundaries upon heat treatment, whose extent is amplified during subsequent creep. Such weak regions experience dislocation creep, leading to strain localization and acceleration of grain-boundary sliding. Adding Ni and Co, individually or in combination, leads to the formation of grain-boundary precipitates (Al9Co2, Al3Ni2) which are resistant to coarsening, thus suppressing the formation of θ′-Al2Cu precipitate-free zones. This microstructure provides high creep resistance at stresses up to 75–80 MPa, with strain rates much lower than in unmodified Al-5.0Cu-0.3Mn-0.2Zr. Adding Fe, which results in extensive decoration of grain boundaries with coarsening-resistant Al7Cu2Fe, and then increasing the Cu content to compensate for the Cu loss to this new phase, leads to a new Al-7.4Cu-1.6Fe-0.3Mn-0.2Zr alloy with creep resistance at 300 °C that surpasses known cast aluminum alloys. Adding Fe to improve the creep resistance of Al-Cu alloys is both cost-effective and sustainable. Our findings offer guidelines applicable to various alloy systems on controlling the evolution of precipitate-free zones and its ensuing effects on creep deformation.

Effect of rare earth Ce and Y on microstructure and viscosity of ZL114A alloy

To investigate the impact of rare earth on the fluidity of casting aluminum alloy during the filling process, the study measured the effects of rare earth (Ce, Y) content and the mischmetal (Ce / Y) on the viscosity of ZL114A alloy melt using a viscosimeter. The results show that for a single rare earth element, when the addition amount of Ce and Y is 0.4 wt%, the grain size and viscosity reach a minimum, with average grain sizes of 45.42μm and 43.54μm respectively, and the solidification range decreases by 4.23°C and 4.61°C respectively, with Y having a better effect than Ce; compared with the alloy without rare earth elements, the grain growth mode changes from independent nucleation to outward extension form. For mixed rare earth elements, the refinement effect is better than that of a single rare earth element, but the viscosity is higher. When the Ce/Y mass ratio is 1/3, the grain size and viscosity reach a minimum, with an average grain size of 40.75μm and a solidification range shortened by 8.92°C; when the proportion of Y is higher, the alloy shows better refinement of the microstructure and viscosity improvement. Rare earth elements have the potential to enhance the fluidity and solidification structure of ZL114A alloy. This study offers valuable technical insights for optimizing the casting process and mold design.

Sub-rapid solidification microstructure characteristics and control mechanisms of twin-roll cast aluminum alloys: A review

Rapid growth in industrial sectors such as automotive and shipbuilding has highlighted the significance of strip casting technology to produce lightweight alloys, particularly aluminum alloys widely used in both industrial production and daily life. Twin-roll casting (TRC), as an economically and environmentally friendly method for slab/strip production and processing, has attracted significant interest from researchers. However, the development of TRC aluminum alloys faces many challenges due to limited understanding of microstructural characteristics and control mechanisms. To further enhance comprehension of TRC aluminum alloys, this article reviews the influencing parameters, control methods, and existing issues related to TRC sub-rapid solidification (SRS) microstructure. It firstly summarizes TRC equipment types and their solidification characteristics, followed by a detailed analysis on key parameters affecting the evolution of TRC microstructure including rolling speed, roll separation force (RSF), and heat transfer coefficient (HTC). Finally, solutions to TRC defects are summarized and evaluated alongside their underlying mechanisms. This article provides a comprehensive review of the characteristics and control mechanisms of TRC microstructure while offering valuable insights for the future production of high-quality TRC aluminum strips.

Casting Production in Poland Versus European Trends in 21st Century

This article presents changes of the total casting production volumes and of the production of castings made from basic casting alloys in Poland, in Europe and worldwide in years 2001–2021. Analogous casting production parameters were compared for Poland, Europe and countries being the leading European and global manufacturers in years 2001, 2011 and 2021. The leading casting manufacturers in Europe (with the manufacturing volume exceeding 1 million tons in the mentioned years) include Germany, Italy, the Ukraine, France and Spain. For years, the largest casting manufacturer worldwide has been China. In 2001–2021, global casting production increased from ca. 68 million tons to ca. 97 million tons (i.e. by ca. 42%), whereas the European one decreased from ca. 17 million tons to ca. 12 million tons (i.e. by close to 30%). In the analyzed period, the Polish production volume grew from ca. 0.75 million tons to ca. 0.88 million tons (i.e. by ca. 17%). The presented data reveal the decreasing importance of gray cast iron and cast steel and the increasing one of ductile cast iron and aluminum alloys. However, the Polish average annual growth rate for aluminum alloy casting production was 10.3%, whereas the global one was 3% and the European one 0.7%.

Microstructural and mechanical properties of Al-Al2O3 micro and nanocomposite fabricated by stir casting

ABSTRACT The current study examines the relationship between the microstructure and tribological characteristics of Al-Si alloy composites reinforced by secondary phase nano SiC particulates synthesis via the stir casting process. The results of wear testing of stir-cast SiC metal matrix composites including up to 12 weight percent fine (75–100 µm) and coarse (125–150 µm) size particles were obtained from cast aluminium alloy. It was discovered via microstructural investigation that the aluminium alloy and SiC particles have good interface bonding. However, at greater amounts (12 wt.%) of fine size reinforcement, clustering of reinforced particles is observed. In addition, results state that finer size particles agglomerate more in the matrix than coarser size particles at greater reinforcement levels. In addition, increasing the amount of SiC particles in the matrix enhanced the hardness of the base alloy. However, when the size of the SiC particles was reduced, the hardness of the composite increased dramatically. Better wear resistance was observed for higher SiC reinforcement levels, while higher forces were also associated with a corresponding increase in wear rate. A combined mode of adhesive and abrasive wear mechanisms is responsible for composite wear, according to a scanning electron microscopy (SEM) investigation of worn surfaces.

Nanotechnology-Enabled Rapid Investment Casting of Aluminum Alloy 7075

Abstract Rapid investment casting with additively produced molds can offer excellent surface finishes, tight dimensional tolerances, and complex geometries for high-performance metal parts in a rapid fashion. However, there is a long-standing challenge in the investment casting of high-strength aluminum alloy (AA) 7075 due to its hot cracking susceptibility and severe solidification shrinkage. Here, we show the unprecedented rapid investment casting of AA7075 by applying nano-treating technology, whereby a low-volume fraction of nanoparticles is dispersed into metal to modify its solidification behavior and microstructure. TiC nanoparticles were able to effectively modify both primary and secondary phases while suppressing the hot cracking susceptibility of AA7075 during solidification. Despite the low cooling rate, nano-treated AA7075 exhibits fine equiaxed grains with an average size of 47.1 μm, in contrast to the large dendritic grains measuring 714.8 μm in pure AA7075. Nano-treated AA7075 parts produced by rapid investment casting exhibited exceptional tensile strength and ductility in both as-cast and heat-treated conditions. This study highlights the potential of investment casting high-performance alloys which were traditionally considered impossible to fabricate by this method.

Critical Challenges in the Anodizing Process of Aluminium–Silicon Cast Alloys—A Review

The microstructure of the substrate plays a crucial role in the anodizing process. Anodizing cast aluminum alloys is quite challenging due to the higher levels of alloying elements present compared to pure aluminum. Elements such as silicon, iron, and copper significantly impact the growth and quality of the anodic layer. Additionally, anodizing parameters such as electrolyte composition, current density, and temperature are critical in determining the morphology and thickness of the anodic film. The casting process, surface condition, and post-treatment also affect the properties of the anodic layer. Optimizing these parameters is essential to achieve a durable and high-quality anodic layer. This work aims to provide a comprehensive understanding of the various factors affecting the anodizing of cast aluminum alloys and the properties of the anodic layer, including its thickness, corrosion resistance, and wear resistance.

Methods of neutralization of iron-containing phases in cast aluminum alloys of the Al-Si-Cu system with iron content of up to 1,5 mass. %

The article discusses the effectiveness of various modifiers, namely chromium (Cr), molybdenum (Mo), vanadium (V), and cobalt (Co), in neutralizing the negative impact of iron on the properties of aluminum alloys in the Al-Si-Cu system by altering the morphology of iron-containing phases. The current advancements in the modification of aluminum alloys are examined, focusing on the influence of these elements on microstructural changes and mechanical properties. An in-depth analysis of the microstructure was conducted, and the optimal concentrations of the modifying elements were identified to achieve enhanced mechanical characteristics. The study highlights that the addition of Cr, Mo, V, or Co facilitates the formation of a fine-grained structure and significantly reduces the size of iron-containing phases to approximately 10 μm. Furthermore, the research elaborates on the thermodynamic interactions between iron and the modifying elements, providing insights into the mechanisms by which these modifiers influence the crystallization process and phase distribution within the alloy. This study opens new avenues for the development of high-performance aluminum alloys with optimized microstructures through precise control of modifier concentrations. The improved alloys exhibit superior mechanical properties, making them suitable for applications in various industrial sectors, including automotive and other industries, where high strength and reliability are critical. Experimental results demonstrate that the strategic addition of Cr, Mo, V, and Co can effectively mitigate the adverse effects of iron inclusions, leading to alloys with enhanced ductility, tensile strength, and overall performance. The findings suggest that these modifiers not only refine the grain structure but also promote a more uniform distribution of phases, thus improving the alloy's resistance to cracking and other forms of mechanical failure. The insights gained from this research provide a valuable foundation for further exploration and optimization of aluminum alloys for high-demand applications, emphasizing the critical role of microstructural engineering in achieving desired material properties

An inverse estimation of frozen sand mold-melt heat transfer coefficient in the solidification of A356 alloy

Casting aluminum alloys is widely used in aerospace, rail transportation, automotive, ships, and other fields. The frozen sand mold casting (FSMC) technology provides a greener and low-cost solution for the sand mold casting industry, which has a better operating environment than the resin sand mold casting and a higher degree of subcooling for solidification process. The interfacial heat transfer coefficient (IHTC) is a significant parameter that affects the structure and properties of the frozen casting. It is also an important boundary condition in numerical simulation. In this paper, a frozen sand mold casting (FSMC) process thermal conductivity problem (IHCP) inversion model is proposed based on the 1-D heat transfer assumption using a combination of finite difference method (FDM) and conjugate gradient method (CGM). The inversion model is validated for its rationality and accuracy in terms of experiments and numerical calculations, respectively. The IHTC is determined under various frozen sand mold casting conditions, including different initial frozen temperatures, water contents, and molding sand. The accuracy of results is verified by comparing the experimental and numerical data. A new method is provided for determining IHTC in frozen casting.

Challenges by latent heat calculation – Competition among analytical and computational methods

Determining the latent heat of multi-component cast aluminum alloys is complex. These alloys solidify within the mushy zone, with their latent heat release influenced by factors like composition, cooling rate, and microstructure. Techniques such as DSC and DTA, along with software tools like JMatPro, FactSage, and ThermoCalc, can determine this value, understand solidification parameters, and calculate latent heat. This paper introduces a novel approach using Newtonian, Fourier, and Energy Balance methods simultaneously, for the first time, to calculate the latent heat of pure aluminum and its AlSi7Cu1 alloy. These methods offer advantages in foundry conditions and require no specialized operator for data interpretation. Commercial software typically provides parameters for standard alloys only, necessitating alternative sources for accurate data. Thermal analysis techniques offer a reliable method to acquire missing parameters and calculate latent heat with high precision. Comparing the accuracy of these methods for pure aluminum and its AlSi7Cu1 alloy, using DSC measurement data and commercial software values, indicates successful application on the foundry floor to determine thermophysical properties accurately.

Recent Progress in Creep-Resistant Aluminum Alloys for Diesel Engine Applications: A Review.

Diesel engines in heavy-duty vehicles are predicted to maintain a stable presence in the future due to the difficulty of electrifying heavy trucks, mine equipment, and railway cars. This trend encourages the effort to develop new aluminum alloy systems with improved performance at diesel engine conditions of elevated temperature and stress combinations to reduce vehicle weight and, consequently, CO2 emissions. Aluminum alloys need to provide adequate creep resistance at ~300 °C and room-temperature tensile properties better than the current commercial aluminum alloys used for powertrain applications. The studies for improving creep resistance for aluminum casting alloys indicate that their high-temperature stability depends on the formation of high-density uniform dispersoids with low solid solubility and low diffusivity in aluminum. This review summarizes three generations of diesel engine aluminum alloys and focuses on recent work on the third-generation dispersoid-strengthened alloys. Additionally, new trends in developing creep resistance through the development of alloy systems other than Al-Si-based alloys, the optimization of manufacturing processes, and the use of thermal barrier coatings and composites are discussed. New progress on concepts regarding the thermal stability of rapidly solidified and nano-structured alloys and on creep-resistant alloy design via machine learning-based algorithms is also presented.

Simultaneously improving mechanical properties and electrical conductivity of Al-1.9Mn alloys with different Mg and Si addition

A simultaneous achievement of high strength and toughness, as well as high conductivity in traditional Al-1.9Mn cast aluminum alloy used in the manufacture of water-cooled radiator shells has proven to be challenging. The addition of Mg and Si elements was implemented in the cast aluminum alloy for a modified treatment to solve the problem. The results showed that the inclusion of Si facilitated the transformation of the plate-like Mn-rich phase (Al6Mn) in the initial Al-1.9Mn alloy into a Chinese-script phase (Al15Mn3Si2) in the new Al-1.9Mn alloy. A higher Si content resulted in an increased volume fraction of Al15Mn3Si2 and a decreased solid solution of Mn in the matrix. Furthermore, a high content of Mg (0.9 wt%) in the Si modified Al-1.9Mn alloy resulted in a notable property reduction, not only in its elongation, but also in its electrical conductivity. It can be attributed to the formation of Mg2Si and the increased solid solution of Mg in the matrix. Through the optimization of the Mg and Si contents, new Al-1.9Mn alloys with superior mechanical properties and excellent electrical conductivity were successfully developed. With the addition of 0.45 wt% magnesium and 0.75 wt% silicon, the new Al-1.9Mn alloy increased its tensile strength to 170 MPa and yield strength to 88 MPa while maintaining 10 % elongation. At the same time, its electrical conductivity increased by 10.7 % compared to the original Al-1.9Mn alloy. The addition of magnesium and silicon elements can achieve a simultaneous enhancement of both the strength and electrical conductivity of the Al-1.9Mn alloy. This holds the potential to meet the usage requirements for cast aluminum alloys used in water-cooled radiator shells.

Effect of Sodium Tripolyphosphate on The Morphology and Thermal Properties of Anorthite-Based Ceramic Foam Filters for Aluminum Alloy Castings

Effect of Sodium Tripolyphosphate on The Morphology and Thermal Properties of Anorthite-Based Ceramic Foam Filters for Aluminum Alloy Castings

Design and Development of LM24 plate Casting using Solid Cast Simulation Technique

Abstract: This research deals with the elimination of defects in aluminium alloy castings and enhancement in the casting yield and quality. The main intention of the work is to improve the quality of a cast component using Computer Aided Casting Simulation Software. SOLID Cast simulation software is used for simulating the solidification process of casting and visualizing outputs showing possible problematic areas or defects which may occur in the cast product. Plate Castings of aluminium alloy - LM 24 are produced with different designs of gating systems and tested for defects like porosity using Archimedes immersion Technique and also Radiographic testing is used to check the quality of the castings. The produced castings are observed to be sound, and the results obtained are in agreement with the simulation results. Hence it is verified that solidification simulation helps in improving the quality of castings without any shop-floor trails. Casting yield and percentage porosity values are determined for 12 castings produced with different gating systems. The best results are observed to be produced by the castings having a 1-Ingate system in horizontal or lateral positions.

Complementary corrosion protection of cast AlSi7Mg0.3 alloy using Zr-Cr conversion and polyacrylic/siloxane-silica multilayer coatings

Aluminium cast alloy AlSi7Mg0.3 is a lightweight metal commonly used in automotive, aeronautical and mechanical applications. It has good corrosion resistance but, under harsh operative conditions, would benefit from additional protection. In this study, a corrosion-protective multilayer coating system for AlSi7Mg0.3 based on hexafluoro-zirconated trivalent chromium coating (Zr-CrCC) and polyacrylic/siloxane-silica (PEHA-SS) coating was developed. The Zr-CrCC was formed by immersion of the substrate in a commercial conversion bath (SurTec® 650). PEHA-SS synthesis was based on organic precursors (2-ethylhexyl acrylate and [3-(methacryloyloxy)propyl]trimethoxysilane) and an inorganic precursor, tetraethyl orthosilicate. After deposition on AlSi7Mg0.3, each coating was first characterised individually, followed by the analysis of the multilayer using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The adhesion of the coatings was evaluated with a cross-hatch cut test. The corrosion studies in sodium chloride solution using electrochemical impedance spectroscopy and salt spray testing showed that the multilayer system is superior to individual Zr-CrCC and PEHA-SS coatings. After 4 months in 0.1 M NaCl, the multilayer-coated samples exhibited the impedance at 10 mHz in the range of GΩ cm2, while scribed samples withstood the corrosion attack in a salt spray chamber for one week. Thus, albeit only about 100 nm thick, the Zr-CrCC deposited between the substrate and a 9-micrometre thick barrier sol-gel PEHA-SS coating acts as an active corrosion protection interlayer and contributes to the overall protectiveness of the multilayer system.

Enhancing surface integrity and performance of EDM with sustainable dielectrics and electrode modifications

A common non-traditional method for precise machining of hard materials is electro-discharge machining (EDM). The efficiency and surface quality in the EDM process are decided by the design and type of the electrodes. Because of its lightweight, cost-effectiveness and easy machinability, aluminium is employed in a wide range of applications. In this work, AlSi10Mg electrodes are manufactured by different processing routes such as 3D printing, casting, and extrusion. Different characterization techniques are carried out to determine the mechanical, electrical, and thermal properties of all differently processed aluminium alloy electrodes. The processing route influence during the EDM of Ti-6Al-4V is evaluated with different levels of operating parameters using conventional EDM oil and lemon peel biodiesel as dielectrics. The experiments are performed with 3 different levels of current (Ip) and pulse on time (Ton) with a constant voltage. The output responses viz. material removal rate (MRR), Tool wear rate (TWR), average surface roughness (Ra) and white layer thickness (WLT) are considered to compare the EDM performance exhibited by differently processed aluminium alloy electrodes. The 3D printed aluminium alloy electrode produces about 23% less TWR and 18% improved surface quality than the conventional (extruded) electrode. The performance exhibited by the cast aluminium alloy electrode is sub-optimal when compared to electrodes processed by the other two routes. The microscopic examination revealed that WLT could be reduced to the extent of about 29% and 39% with 3D printed AlSi10Mg electrodes when compared with extruded and cast electrodes. The present study concluded that a 3D printed electrode with lemon peel dielectric is the most preferable combination for high surface finish operation.

Evaluation of Two New Cast Aluminum Alloys for High Performance Cylinder Heads

Evaluation of Two New Cast Aluminum Alloys for High Performance Cylinder Heads

Correction: Research progress on microstructure tuning of heat-resistant cast aluminum alloys

Correction: Research progress on microstructure tuning of heat-resistant cast aluminum alloys

Data extension-based analysis and application selection of process-composition-properties of die casting aluminum alloy

This research aims to provide a solution to the scarcity and fragmentation of industrial data on die casting aluminum alloys. Quantifying the coupling between die casting process-composition-properties of aluminum alloys through small datasets, is a critical step in predicting part properties and optimizing process selection. To visualize the connections and discuss the effect of the interaction between different parameters on the property, data is fed into a self-organizing mapping model. Whereafter, an innovative data extension method is proposed to predict both yield and tensile strengths with more than 96% accuracy using a small data set. Moreover, two novel methods of multi-parameter combined range selection, the multi-objective optimization based on the agent model and the superimposition of the contour map, are guided by being informed in which region the mechanical properties fall. Finally, the feasibility of application range selection method is verified experimentally. Mapping based on data-driven process-composition-properties relationships and the free combination of application ranges are reliable theoretical solutions which are valuable for practical applications.