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To enhance the scuffing resistance of Al-Si alloy cylinder liners, mechanical honing shaping was employed. Comparisons were made with untreated and chemically etched Al-Si alloy cylinder liners. The scuffing resistance properties were evaluated using a starved lubrication test method. CrN piston rings (coated via PVD) and Chrom-Keramik-Schicht (CKS) piston rings were used in the tests against the cylinder liners. A stress contact model was established based on the state of silicon particles to analyse the scuffing resistance mechanism. The results indicated that the PVD piston ring exhibited superior scuffing resistance compared to the CKS piston ring. This improvement is attributed to the numerous small holes on the surface of the PVD piston ring, which effectively store oil. The mechanically honed Al-Si alloy cylinder liner demonstrated the best scuffing resistance properties. When paired with the PVD piston ring, the friction coefficient of the mechanically honed Al-Si alloy cylinder liner decreased by 17%, and the scuffing time increased fivefold. Finite element analysis revealed that the silicon particles protruding on the surface of the mechanically honed Al-Si alloy cylinder liner had a rounded shape, resulting in lower stress during friction. [ABSTRACT FROM AUTHOR]

The semi-solid slurry preparation process, microstructure, and mechanical properties of truck coarse filter bracket were studied in this paper. The semi-solid aluminum alloy slurry with high solid fraction was prepared by the Slurry Enthalpy Equilibrium Device (SEED) method, and the optimum slurry preparation parameters were determined through the observation and analysis of the slurry microstructure as follows: pouring temperature 700 °C, rotation speed 180 r/min, and crucible temperature 400 °C. The average grain size and shape factor of the slurry prepared under these conditions are 50.448 μm and 0.799. Die casting trial production which used the best process parameters of slurry preparation and die casting was carried out. The results show that the die casting parts are completely filled with no obvious surface defects. It can be seen from the cutting experiment and X-ray non-destructive test that the internal structure is dense and uniform, and there are no obvious casting defects that were observed such as cracks and holes. The semi-solid die castings were strengthened by T6 heat treatment. The experimental results showed that the optimal heat treatment parameters were a solution temperature of 470 °C and time of 4 h, aging temperature of 175 °C and time of 12 h. Under these conditions, the microstructure morphology was improved significantly. The tensile strength and yield strength reached 342.1 MPa and 309.1 MPa, respectively, which were 38.9% and 95.3% higher than the semi-solid state, and the elongation was 4.5%. [ABSTRACT FROM AUTHOR]

We employed a melt ultrasonic treatment near the liquidus to prepare a high-thermal-conductivity Al-4Si-2Ni-0.8Fe-0.4Mg alloy. The influences of various ultrasonic powers on its microstructure, mechanical properties, and thermal conductivity were investigated. It is shown that near-liquidus ultrasonication significantly refines the alloy grains and eutectic structure, synergistically improving the alloy's mechanical properties and thermal conductivity. Specifically, the grain size decreased by 84.5% from 941.4 to 186.2 µm. Increasing the ultrasonic power improved the thermal conductivity of the alloy slightly and significantly enhanced its mechanical properties. At an ultrasonic power of 2 100 W, the tensile strength, yield strength, elongation rate, and thermal conductivity were 216 MPa, 142 MPa, 6.3%, and 169 W/(m·k), respectively. [ABSTRACT FROM AUTHOR]

To better comprehend the machinability studies during MMCs, the effect of cutting tool while machining MMCs, the cutting forces that induce and importantly the influence of cutting tool were carried out. Polycrystalline diamond (PCD) and uncoated tungsten carbide (K10) cutting tools were used to machine a eutectic (Al-12wt% Si alloy) and a hypereutectic (Al-17wt%Si) matrix material with Silicon Carbide (SiCP) and Aluminium Oxide (Al2O3P) in the particulate form at 0, 5, 7.5, and 10 volume percent volume fractions as MMCs. To further characterize the machinability of the composites, SEM analysis of chips created during machining and the cutting inserts was performed. Based on the results of the MMC machining operations, the Built-up Edge (BUE) development on the K10 insert has caused it to exert significantly higher cutting forces than the PCD. Machining of SiCp and Al2O3P reinforced Al-Si alloys utilizing K10 insert showed a comparatively bigger difference in cutting forces, indicating that the cutting forces exerted by PCD did not significantly alter with varied composite composition.

The wear tests of aluminum based automotive alloys with different Si content in 3.5% NaCl, seawater and dry sliding environment are carried out. A conventional pin-on-disc wear apparatus is used at 2.55 MPa pressure and 0.51 m/s speed for a sliding distance of 923.2 m. The results show that the wear rate and friction coefficient of the alloy decreases with the increase of silicon content up to the eutectic point in all sliding environments. Among the different Si-rich intermetallics formed, especially Mg2Si strengthens the alloys. It is more prominent in the case of a corrosive environment through creating MgO plus SiO2 layers, which protect the corrosive wear and reduce the friction coefficient. Wear test surfaces have shown that Si addition makes the alloys wear-resistant with smooth abrasive grooves covered with oxides.

Aluminum alloys are widely used in various industries due to their as low density, high strength-to-weight ratio, and good corrosion resistance. However, their wear resistance is often inadequate for certain applications. Utilization of industrial waste materials, such as iron slag, as reinforcement in aluminum alloy matrix composites offers a sustainable approach to material development and waste management. The utilization of industrial waste materials for aluminum alloy matrix composite fabrication offers a waste utilization to material development. The loading of this reinforcement varied from 0 to 15 wt.% and different particle size range (220-140, 140-70, and 70-0 µm). A microscopic analysis indicated that the iron slag particles are spread uniformly inside the metallic matrix. There is also a reduction in the size of primary silicon, as well as morphological changes (acicular to globular shape). The wear behavior was calculated using a pin-on-disk wear set up in accordance with ASTM G99 standard. The composites were employed to dry sliding wear test under various operating conditions such as applied pressure (0.2–1.4 MPa), and sliding distance (0–3000 m). The 15F composite outperformed all other composite samples in terms of wear rate under all working conditions. When compared to the base alloy, it demonstrated a remarkable 67% drop in steady state wear rate. The enhancements in wear performance for the 15F composite were attributed to the effects of Fe slag reinforcement. The inclusion of iron slag particles induced strong interfacial bonding between matrix and reinforcement particles improving the durability of the mechanical mixed layer developed during relative motion. Importantly, the wear rate parameters of the 15F composite were similar to those of the brake drum material used in commercial applications. This emphasizes the composite suitability for usage in a variety of automobile components. [ABSTRACT FROM AUTHOR]

The unsatisfactory mechanical performance at high temperatures limits the broad application of 3D‐printed aluminum alloy structures in extreme environments. This study investigates the mechanical behavior of 4 different lattice cell structures in high‐temperature environments using AlSi12Fe2.5Ni3Mn4, a newly developed, heat‐resistant, high‐strength, and printable alloy. A novel Antisymmetric anti‐Buckling Lattice Cell (ASLC‐B) based on a unique rotation reflection multistage design is developed. Micro‐CT (Computed Tomography) and SEM (Scanning Electron Microscope) analyses revealed a smooth surface and dense interior with an average porosity of less than 0.454%. Quasi‐static compression tests at 25, 100, and 200 °C showed that ASLC‐B outperformed the other 3 lattice types in load‐bearing capacity, energy absorption, and heat transfer efficiency. Specifically, the ASLC‐B demonstrated a 51.56% and 44.14% increase in compression load‐bearing capacity at 100 and 200 °C compared to ASLC‐B(AlSi10Mg), highlighting its excellent high‐temperature mechanical properties. A numerical model based on the Johnson‐Cook constitutive relationship revealed the damage failure mechanisms, showing ASLC‐B's effectiveness in preventing buckling, enhancing load‐transfer efficiency, and reducing stress concentrations. This study emphasizes the importance of improving energy absorption and mechanical performance for structural optimization in extreme conditions. The ASLC‐B design offers significant advancements in maintaining structural integrity and performance under high temperatures. [ABSTRACT FROM AUTHOR]

The Al-Si alloy prepared by the traditional powder metallurgy method has the problems of difficult sintering and low mechanical properties. In this paper, rotary extrusion combined with rapid solidification/powder metallurgy technology (RS/PM) is proposed and designed to produce an Al-10Si alloy. In subsequent sintering at different temperatures, better metallurgical bonding between particles can be achieved to fulfil the aim of improving the mechanical properties of the material. Additionally, the continuous preparation of materials can be achieved. Finally, it is verified that the density of the Al-10Si alloy sintered at 525 °C is 2.61 g/cm3, reaching 97.0% of the theoretical density, and the tensile strength reaches 336 MPa, which is much higher than that of the alloy prepared by the traditional casting method and powder metallurgy method. [ABSTRACT FROM AUTHOR]

This study investigates the impact of strontium (Sr) additions on the corrosion resistance of an LM6 (A413) aluminium alloy. By incorporating varying concentrations of Sr (0.01 wt.% and 0.05 wt.%), the morphological and corrosion behaviours of the alloy were analysed under different corrosive environments, including sulphuric acid, sodium hydroxide, and sodium chloride solutions. The results demonstrate that Sr modifications significantly enhance the alloy's corrosion resistance, with the most substantial improvement observed at 0.05 wt.% Sr. The analysis revealed that the weight loss of the alloy in sulphuric acid decreased by 2.5% with 0.05 wt.% Sr after 10 days of immersion, due to the formation of a stable passive oxide layer. In sodium hydroxide, however, the weight loss was reduced by 5% with 0.05 wt.% Sr after 10 days, indicating aggressive uniform corrosion. In the 3.5% sodium chloride solution, the corrosion rates remain relatively low, and the 0.05 wt.% Sr alloy showed a decrease in corrosion product formation over time, suggesting enhanced resistance. Detailed surface analyses, including 3D profiling and morphology assessments, revealed that Sr additions refine the eutectic silicon phase, transforming it from a coarse to a more desirable fibrous or lamellar structure, thus improving the alloy's overall performance. The innovative findings underscore the potential of Sr as an effective microstructural modifier for enhancing the durability and longevity of Al-Si alloys in corrosive environments. [ABSTRACT FROM AUTHOR]

The optimization of processing parameters is indispensable for the laser powder bed fusion (L-PBF) process. The deposited energy density (DED) is one of the process indexes for the L-PBF process and has a simplified formula of P·v-0.5, where P is the laser power, and v is the scan speed. This parameter describes the change in the relative density and the melt pool morphology with laser power and scan speed well, whereas it does not include the effect of other processing parameters, e.g., hatch spacing (S). In the present study, an attempt was made to incorporate the effect of S into DED. Al-12Si (mass％) alloy cube samples were fabricated by L-PBF under various P, v, and S, for evaluating the relative density and the melt pool morphology. The melt pool depth and width of L-PBF-manufactured Al-12Si alloy increased linearly with P·v-0.5 and did not exhibit a clear correlation with S. Based on the experimental observation, the effect of hatch spacing on DED was estimated to be S-0.5, and a new index of P·v-0.5·S-0.5 was proposed. This index described the change in the relative density of the L-PBF-manufactured Al-12Si alloy with laser conditions (P, v, and S) well when the thermal conduction mode melting was dominant. This study also indicated the limitation of the applicability of P·v-0.5·S-0.5 under the keyhole or transition mode melting. [ABSTRACT FROM AUTHOR]

The influence of ageing and ageing time on the mechanical properties, such as tensile strength and wear behaviour, of Al18Si3.6Cu0.34Ce alloy have been discussed. The As-cast alloy was subjected to T6 heat treatment (solutionization at 510° for 1 hr and ageing at-210°C) for different ageing durations like 1 hr, 3 hr, 5 hr and 7 hr, the morphology of as-cast and age hardened samples is examined by SEM and optical images, the sharp edges of primary-silicon and α-Al matrix with a columnar grain structure of untreated alloy changed after ageing, they are rounded off, spheroidisation with uniform redistribution of Al2Cu blocks, Al2CeSi intermetallic precipitates are formed with improved grain boundaries, and it develops obstacles in larger scale to the flow of dislocation mechanism, so it strengthens the metal matrix. Compared to as-cast alloy, the mechanical properties are improved after ageing. For 5-hr aged samples, the yield strength (YS) elevated to 127.44 MPa (improved by 83%) with an elongation rate of 1.64% (41.4%) as compared to as-cast alloy, and the ultimate tensile strength of as-cast alloy (158.2 MPa) enhanced to 193.835 MPa and 168.7 MPa after 1 hr and 3 hr ageing, respectively. Ageing improves the flow stress, which is predominantly the effect of homogenisation. Considerable improvements in the wear resistance after age hardening were noticed; both VWR and COF both a linear relation, with applied load at constant speed. As-cast and 7-hr aged samples show poor wear resistance due to co-existence of incoherent phases (Al2Cu and Si) in the metal matrix, and alloy ageing for 1 hr, 3 hr and 5 hr improves the load bearing and shear strength. [ABSTRACT FROM AUTHOR]

Al–Nb–B refiner has been considered as an alternative to Al–Ti–B refiner for hypoeutectic Al–Si alloys due to Si-poisoning effect. In this paper, the effects of Al–Nb–B and Al–Ti–B refiner on the microstructure and mechanical properties in indirect squeeze casting Al–8Si-0.2Mg-0.5Mn alloy were compared. Results show that the grain sizes in the edge chilling layer, segregation band, and the center region of the Al–Nb–B refined alloys were refined by 13.9%, 12.5%, and 17.6% compared to Al–Ti–B refined alloys, respectively. The yield strength, tensile strength, and elongation of Al–Nb–B inoculated alloys were superior to those of the unrefined alloys and Al–Ti–B inoculated alloys. The coexistence of NbAl3 and NbB2 particles in the Al–Nb–B refiner exhibited excellent anti Si-poisoning capability. They significantly decreased the grain size and uniformly distributed the eutectic Si particles and Fe-rich phases, resulting in an increase in the yield strength of the alloy by 16.1% compared to the Al–Ti–B inoculated alloy. The distribution of iron-rich phases in the segregation band was affected by the inoculation. The size of α-Al15(Fe, Mn)3Si2 phase in Al–Ti–B inoculated alloys was refined, and the number significantly increased, resulting in a decrease in tensile strength of 12.82 MPa. In the Al–Nb–B inoculated alloys, the size and number of α-Al15(Fe, Mn)3Si2 phase decreased, and the δ-Al4FeSi2 phase increased, which effectively improved the fracture toughness and ductility. In addition, with the increase in grain refinement (from unrefined to Al–Ti–B to Al–Nb–B inoculated alloy), the fracture behavior changed from trans-granular fracture to intergranular fracture, improving the fracture toughness.

Recent advances in artificial intelligence have opened up new avenues for microstructure characterization, notably in metallic materials. Physical and mechanical properties generally depend on the microstructure of the metallic material. On the other hand, microstructural characterization takes time and calls for specific techniques that don’t always lead to conclusive results quickly. To address this issue, this research focuses on the application of artificial intelligence approaches to microstructural categorization. We demonstrate the advantages of the AI approach using an example of Al-Si alloy, a material that is widely employed in a variety of industries. To specify a suitable convolutional neural network (CNN) approach for the microstructural classification of the Al-Si alloy, CNN models were trained and compared using DenseNet201, Inception v3, InceptionResNetV2, ResNet152V2, VGG16, and Xception architectures. Resulting from the comparison, it was determined that the developed supervised transfer learning model can execute the microstructural classification of Al-Si alloy microstructural images. This paper is an attempt to advance methods of microstructure recognition/classification/characterization by using Deep Learning approaches. The significance of the established model is demonstrated and its accordance with the literature data. Also, necessity is shown of developing material models and optimization through systematic microstructural investigation, production conditions, and material attributes.

In the process of preparing polycrystalline silicon using Al-Si alloy purification, the enrichment of primary silicon can effectively reduce the consumption of aluminum and acid in the subsequent pickling process, thereby lowering the separation cost of high-purity primary silicon. Electromagnetic directional solidification is one of the best methods for preparing polycrystalline silicon currently due to its advantages such as simple process and strong controllability. However, there is a lack of systematic research on how various process parameters affect the enrichment of primary silicon. Therefore, this study investigates the effects of initial solidification temperature, crucible initial position, and descent rate on the behavior of primary silicon enrichment during the solidification process of Al-50% Si (mass fraction) alloy, and characterizes the morphology of primary silicon grains within the enrichment zone. The results show that when the initial solidification temperature is 950 ℃, the initial crucible position is -5 mm, and the crucible descent rate is 2 mm/h, primary silicon is mainly concentrated in the lower part of the ingot with a maximum enrichment rate of 79. 1%, which is the optimal combination of processes. At the same time, as the degree of primary silicon enrichment increases, the primary silicon grains change from "disk-like" to coarse "spherical", which helps reduce the inclusion of primary silicon and improve its purity. [ABSTRACT FROM AUTHOR]

The evaluation of mold properties is crucial in the foundry industry to ensure efficient and high-quality casting production. This study focuses on the assessment of mold properties using silica sand, copper slag, and their mixture as molding materials in the sodium silicate, CO2 (carbon dioxide) chemical binder process. The properties investigated include mold hardness, permeability, and compressive strength. The aim is to evaluate their suitability and performance in comparison with traditional molding materials. The results indicate that a mixture of 6% sodium silicate and 15 sec of CO2 gas passing is highly effective in achieving optimum mold properties for both slag and sand molds. These properties remained stable even after prolonged exposure to different weathering conditions, highlighting the durability of the molds. Furthermore, the study revealed that the combination of sand and slag yields mold properties that lie between those of the pure ingredients. Specifically, a mixture comprising 80% sand and 20% slag exhibited the most desirable properties. Additionally, investigations were conducted using a 20% sand and 80% slag mixture, which demonstrated improvements in mold properties. In terms of material substitution, the evaluation of mold properties using the CO2 process showed that copper slag displayed similar characteristics to sand. This finding suggests that copper slag can serve as a suitable alternative to partially or fully replace silica sand in mold-making applications. [ABSTRACT FROM AUTHOR]

The present work investigated the effect of flat, concave, and convex mold contours on heat transfer during the solidification of an aluminum AlSi11Cu3Fe (ADC-12) alloy. Experiments were designed with copper/steel cylindrical and flat molds to study the effect of convex and flat casting/mold interface on heat transfer. To examine the effect of a concave and flat interfaces, an experimental setup consisting of a cylindrical and square bar chill was fabricated. Casting/mold (chill) interfacial heat flux was estimated by solving an inverse heat conduction problem (IHCP). The temperatures measured at locations inside the mold/chill were used as input to the inverse solver. It was observed that the flat contour yielded higher heat flux than a convex contour for both copper and steel molds. Although the volume to surface area (V/A) ratio for castings solidified against a flat and convex interface are the same, the larger mold volume associated with the flat interface yielded higher heat flux transients. Experiments involving chills suggested that the flat interface resulted in higher heat transfer when the (V/A) ratio for the chill was the same. To study and compare the combined effect of mold material and contour on heat transfer during casting solidification, the molds must have the same volumetric thermal effusivity per unit surface area available for heat transfer. [ABSTRACT FROM AUTHOR]

To better comprehend the machinability studies during MMCs, the effect of cutting tool while machining MMCs, the cutting forces that induce and importantly the influence of cutting tool were carried out. Polycrystalline diamond (PCD) and uncoated tungsten carbide (K10) cutting tools were used to machine a eutectic (Al- 12wt% Si alloy) and a hypereutectic (Al-17wt%Si) matrix material with Silicon Carbide (SiCP) and Aluminium Oxide (Al2O3P) in the particulate form at 0, 5, 7.5, and 10 volume percent volume fractions as MMCs. To further characterize the machinability of the composites, SEM analysis of chips created during machining and the cutting inserts was performed. Based on the results of the MMC machining operations, the Built-up Edge (BUE) development on the K10 insert has caused it to exert significantly higher cutting forces than the PCD. Machining of SiCp and Al2O3P reinforced Al-Si alloys utilizing K10 insert showed a comparatively bigger difference in cutting forces, indicating that the cutting forces exerted by PCD did not significantly alter with varied composite composition. [ABSTRACT FROM AUTHOR]

The wear tests of aluminum based automotive alloys with different Si content in 3.5% NaCl, seawater and dry sliding environment are carried out. A conventional pin-on-disc wear apparatus is used at 2.55 MPa pressure and 0.51 m/s speed for a sliding distance of 923.2 m. The results show that the wear rate and friction coefficient of the alloy decreases with the increase of silicon content up to the eutectic point in all sliding environments. Among the different Si-rich intermetallics formed, especially Mg2Si strengthens the alloys. It is more prominent in the case of a corrosive environment through creating MgO plus SiO2 layers, which protect the corrosive wear and reduce the friction coefficient. Wear test surfaces have shown that Si addition makes the alloys wear-resistant with smooth abrasive grooves covered with oxides. [ABSTRACT FROM AUTHOR]

Near-eutectic Al–Si alloys attracted significant interest in automotive, aerospace, and other industries owing to their superior strength and high-temperature resistance. However, the alloy's narrow solid–liquid temperature range presents challenges in semi-solid processing. In this study, an Enclosed Cooling Slope Channel was used to prepare near-eutectic Al–12Si–4Cu–2Ni–0.8Mg–0.1Gd alloy semi-solid slurry. We investigated the impact of liquid squeeze casting (LSC) and rheo-squeeze casting (RSC) on the alloy's microstructure characteristics and properties of the alloy were explored. Findings indicate that the average size of primary α-Al decreases first and then increases with the rising pouring temperature. Through the RSC process, the ultimate tensile properties of the material are significantly improved, achieving optimal tensile properties at the pouring temperature of 605 °C, with ultimate tensile strength and elongation of 247 MPa and 2.66%, respectively. Compared with LSC samples, the ultimate tensile strength and elongation increased by 44.4% and 116.3%, respectively. This enhancement in properties is credited to the notable reduction in porosity and the spheroidization of primary α-Al. Regarding high-temperature performance, the alloy's tensile strength at a test temperature of 200 °C stands at 194.6 MPa. marking only a only 21.2% decrease from the room temperature result. The precipitation of the thermally stable phase and the solid solution effect of Gd elements effectively hindered the reduction of high-temperature tensile properties. [ABSTRACT FROM AUTHOR]

Al-Si alloys are commonly used in the automotive and aircraft industry because of their excellent strength-to-weight ratio. Due to the laser powder bed fusion manufacturing process, inhomogeneous cooling affects the microstructure as well as defect distributions. Within this paper, the uniform fatigue damage tolerance assessment was further qualified for (miniature) bending specimens with different loaded volumes based on the concepts according to Murakami (√area) and Shiozawa for an initial defect-based model. These approaches were used to calculate defect-related fatigue life curves, in which the cyclic stress intensity factor (ΔK) at the initiating defect (√area) was used to represent local stress concentration at the crack tip instead of nominal stress-based S-N curves. Results of S-N curves did not allow a precise lifetime prediction due to increasing effect of manufacturing-related defect distributions, while fracture mechanical approaches enable a uniform fatigue lifetime description of different testing volumes. The calculated fatigue limit and short crack threshold value suggested by Noguchi based on the extended approach of Murakami need to be compared and validated experimentally. Furthermore, the effects of miniaturization and crack propagation have been identified and considered. Uniform fatigue life predictions and efficient materials testing have been combined and show potential for future research.

Abstract Al‐Si alloys are widely used in automotive casting components while microporosity has always been a detrimental defect that leads to property degradation. In this study, a coupled three‐dimensional cellular automata (CA) model has been used to predict the hydrogen porosity as functions of cooling rate and initial hydrogen concentration. By quantifying the pore characteristics, it has been found that the average equivalent pore diameter decreases from 40.43 to 23.98 μm and the pore number density increases from 10.3 to 26.6 mm−3 as the cooling rate changes from 2.6 to 19.4°C/s at the initial hydrogen concentration of 0.25 mL/100 g. It is also notable that the pore size increases as the initial hydrogen concentration changes from 0.15 to 0.25 mL/100 g while the pore number remains stable. In addition, the linear regression between secondary dendrite arm spacing and the equivalent pore diameter has been studied for the first time, matching well with experiments. This work exhibits the application of CA model in future process optimization and robust condition design for advanced automotive parts made of Al‐Si alloys.

Due to the Si/Zr-poisoning effect, conventional refiners often yield unsatisfactory results in refining α-Al grains for Al–Si alloys. In this work, the refinement of α-Al grains and the modification of eutectic Si are simultaneously achieved through the combined addition of Y and Zr to A356 alloy. The results indicate that the individual addition of Zr aids in refinement due to the formation of heterogeneous nuclei Al3Zr, while Y alone can refine α-Al grains and modify eutectic Si to a certain extent. When Y and Zr are added together, not only is the size of α-Al grains further refined to 22.1 μm, but the morphology of eutectic Si is also completely transformed into a fibrous structure. The interaction between Zr and Y decreases their solubility in the matrix, enhances heterogeneous nucleation, and induces the formation of a Al8FeMg3Si6YxZry phase enriched at grain boundaries, suppressing the growth of eutectic Si flakes. Compared to the use of Al–Ti–B refiners and Sr modifiers, the alloy with 0.25Zr and 0.3Y additions exhibits more significant grain refinement and Si modification. Furthermore, it facilitates the precipitation of fine Al3(Y, Zr) particles during the T6 heat treatment process, resulting in an optimal ultimate tensile strength (UST) of 289 MPa and an elongation of 9.75%.

Based on previous work, where Al-Si-Cu-Ni alloy was successfully manufactured by laser powder bed fusion (PBF-LB/M) technology, in this study, we further observe the microstructure of the alloy, analyze the formation mechanism of the microstructure during solidification, and discuss their implications for the mechanical properties. The results indicate that the microstructure comprises multi-level cellular heterogeneous structures, with an α-Al matrix in the interior of the cellular structure and Cu- and Ni-rich phases clustered at the boundaries, intertwined with the silicon network. During solidification, α-Al solidifies first and occupies the core of the cells, while Si phases and Cu- and Ni-rich phases deposit along the cellular boundaries under the influence of surface tension. During the solidification process of cellular boundaries, influenced by spinodal decomposition and lattice spacing, Si phases and Cu- and Ni-rich phases interconnect and distribute crosswise, collectively forming multi-level cellular structures. The refined cellular microstructure of the PBF-LB/M Al-Si-Cu-Ni alloy enhances the mechanical properties of the alloy. The alloy exhibits a bending strength of 766 ± 30 MPa, a tensile strength and yield strength of 437 ± 6 MPa and 344 ± 4 MPa, respectively, with a relatively low fracture elongation of approximately 1.51 ± 0.07%. Subsequent improvement can be achieved through appropriate heat treatment processes. [ABSTRACT FROM AUTHOR]

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In this study, the friction surfacing of Al–16Si alloy on AA1050 substrate was investigated using experimental and smoothed-particle hydrodynamics simulation methods. The effect of Al–16Si rod rotational speed on microstructure, surface roughness, mechanical properties, and wear resistance of coatings was examined. Both experiment and simulation findings show that by enhancing the rotational speed from 600 to 1000 rpm while reducing the effective width and thickness of the deposited layer, the deposited layer's efficiency decreases from 41 to 14%. By increasing the rotational speed from 600 to 1000 rpm, the interface roughness and surface roughness decreases to 78 and 80%, respectively. According to experiment and simulation results, plastic strain's influence on the grain size is dominant at a high rotational speed (1000 rpm), and by decreasing the rotational speed down to 600 rpm, the effect of temperature is dominant. In addition, the distribution of CuAl2 and silicon particles become more uniform with a decrease in the rotational speed from 1000 to 600 rpm, and the average size of these particles decreases to 0.62 and 4.35 μm, respectively. Compared to the pure aluminum substrate, surfacing with a rotational speed of 600 rpm increases hardness, shear strength, and wear resistance by 224%, 265%, and 60%, respectively. [ABSTRACT FROM AUTHOR]

Recent advances in artificial intelligence have opened up new avenues for microstructure characterization, notably in metallic materials. Physical and mechanical properties generally depend on the microstructure of the metallic material. On the other hand, microstructural characterization takes time and calls for specific techniques that don't always lead to conclusive results quickly. To address this issue, this research focuses on the application of artificial intelligence approaches to microstructural categorization. We demonstrate the advantages of the AI approach using an example of Al-Si alloy, a material that is widely employed in a variety of industries. To specify a suitable convolutional neural network (CNN) approach for the microstructural classification of the Al-Si alloy, CNN models were trained and compared using DenseNet201, Inception v3, InceptionResNetV2, ResNet152V2, VGG16, and Xception architectures. Resulting from the comparison, it was determined that the developed supervised transfer learning model can execute the microstructural classification of Al-Si alloy microstructural images. This paper is an attempt to advance methods of microstructure recognition/classification/characterization by using Deep Learning approaches. The significance of the established model is demonstrated and its accordance with the literature data. Also, necessity is shown of developing material models and optimization through systematic microstructural investigation, production conditions, and material attributes. [ABSTRACT FROM AUTHOR]

The goal of the fluidity test is to evaluate the ability of the melt to fill the cavity of the mold, which is one of the factors affecting the final quality of the castings. It is a technological test that is basically not standardized, therefore it is realized in different forms, for example using "horizontal" and "vertical" molds. The "horizontal" mold makes it easier to fulfill the condition of repeatability, therefore it was used to calculate the capability of the test by the Measurement Systems Analysis (MSA) method. The results of the tests in both molds were used to calculate regression equations that allow the fluidity to be determined with strong reliability based on variables such as melt temperature, casting speed, and mold temperature. In addition, the effects of input data variability (uncertainty) on the resulting fluidity value were analyzed using regression equations and the Monte Carlo simulation. The contribution of the article is the analysis of the capability of the measurement process of the fluidity and a prediction of the results of its tests using the Monte Carlo simulation method. [ABSTRACT FROM AUTHOR]

Silicon has the advantages of high specific capacity (4200 mAh/g), low lithium potential and abundant reserves, and is considered to be one of the most suitable materials for replacing graphite negative electrode. However, the commercial silicon particle size is too large to be used directly as an electrode material, and the silicon material will undergo huge volume expansion during the lithium insertion process, resulting in the fragmentation of the active substance falling off from the fluid collector, resulting in a sharp decline in battery capacity. This defect seriously affects the commercial application of silicon-based anode materials. In this paper, a kind of silicon anode material with porous structure is designed for the defect of silicon anode material. The aluminum-silicon alloy prepared by atomization method presents a three-dimensional porous spherical structure after etching, and the abundant holes reserve space for the volume expansion during the process of lithium silicon embedding and improve the transmission rate of lithium ions. It was found that when the silicon content was 12%, the reversible specific capacity of the material was 1269 mAh/g at 4000 mA/g current density, and the capacity retention rate of 100 cycles relative to the fourth cycle was 59.5%. Compared with ball-ground silicon, the capacity retention rate is increased by 25.7%. Therefore, this paper provides a new idea for the design of porous silicon-based anode materials. [ABSTRACT FROM AUTHOR]

The effect of Y content on the microstructure of A356 aluminum alloy and the mechanical properties of the alloy under T6 heat treatment was investigated. The results show that with the addition of 0.3 wt.% rare earth Y, the grain size of the cast A356 aluminum alloy reaches a minimum and the mechanical properties reach an optimum. After the T6 heat treatment, the grain structure of the alloy was further reduced and the mechanical properties were further improved. Compared to the cast A356 aluminum alloy without Y, the average α-Al grain size is reduced by 53.4%, the secondary dendrite SDAS by 32.2% and the average length of eutectic Si particles by 82.0%. The ultimate tensile strength (UTS) and elongation (El) increased to 280.75 MPa and 14.43% respectively, and the Vickers hardness increased to 102.9 HV. [ABSTRACT FROM AUTHOR]

The effects of Al-5Ti-1B and Sr on the microstructure and properties of ZL101 alloy were studied, and the degree of eutectic Si modification was evaluated by solidification behavior. The results show that Al-5Ti-1B has a great effect on the refinement of primary α-Al dendrites, Sr has a great effect on the modification of eutectic Si, Al-5Ti-1B and Sr have a significant effect on the refinement of α-Al, and most of the eutectic Si is transformed from coarse lamellar to fine fibrous, but an incompletely modified region appears. Thermal analysis shows that the degree of undercooling in the primary α-Al and the nucleation rate is increased by the combined addition of Al-5Ti-1B and Sr, the effect of grain refinement is good, and the growth temperature of eutectic Si in the precipitation stage increases, and the metamorphic effect decreases slightly. More importantly, compared with the unmodified alloy, the alloy with Al-5Ti-1B and Sr addition combined increased the hardness by 9.8% and the electrical conductivity by 8.9%. The influence mechanism of the interaction between Al-5Ti-1B and Sr on the microstructure and properties of the alloy is discussed. [ABSTRACT FROM AUTHOR]

The Al-Si alloy prepared by the traditional powder metallurgy method has the problems of difficult sintering and low mechanical properties. In this paper, rotary extrusion combined with rapid solidification/powder metallurgy technology (RS/PM) is proposed and designed to produce an Al-10Si alloy. In subsequent sintering at different temperatures, better metallurgical bonding between particles can be achieved to fulfil the aim of improving the mechanical properties of the material. Additionally, the continuous preparation of materials can be achieved. Finally, it is verified that the density of the Al-10Si alloy sintered at 525 °C is 2.61 g/cm3, reaching 97.0% of the theoretical density, and the tensile strength reaches 336 MPa, which is much higher than that of the alloy prepared by the traditional casting method and powder metallurgy method.

This study aimed to enhance the mechanical properties of high pressure die casting (HPDC) Al9Si0.6Mn alloys by incorporating in-situ TiB2 particles. The effects of TiB2 addition on the microstructure and mechanical properties of as-HPDC Al9Si0.6Mn alloys were investigated. The results showed that TiB2 addition refined the bimodal grain structure and eutectic Si morphology in the central region of the as-HPDC alloys, which was the primary contributor to the mechanical properties. The thickness of the skin region and band zone increased with increasing TiB2 addition, while the central region exhibited a reduced thickness but remained dominant on the entire cross-section. The optimal TiB2 content was found to be 1 wt%, resulting in the 23.4 % reduction in grain size and 10.7 % enhancement in yield strength. The modified strengthening model based on the microstructure features of the central region accurately predicted the yield strengths of as-HPDC alloys. Finally, the morphological strengthening factors induced by TiB2 particles were analytically illustrated in the HPDC Al9Si0.6Mn–TiB2 alloys.

Aluminum metal matrix composites are increasingly popular nowadays because of their wide range of uses. The low weight and excellent mechanical qualities, such as strength and hardness, of Al-Al2O3 composites make them useful in many fields, including automotive, aerospace, electronics, aeronautics, and military. Most of the engine components are made of aluminum-silicon alloys because of their excellent casting and forming properties. In engine components wear is a crucial parameter to be considered therefore in this investigation Al-Si alloy with varying percentages of V2O5 has been considered to develop the Al-Al2O3 composite and evaluate its tribological aspect. For composite development, a novel in-situ approach has been used with the help of the stir-casting method. The tribological behavior of the different composites was examined experimentally and studied with sliding distance, applied load, and the amount of reinforcement. Composites show a significant increase in hardness relative to the base alloy because of the generation of hard alumina particles within the melt. The wear behavior of in-situ Al-Al2O3 composites was studied using a pin-on-disc setup. In terms of COF and wear rate, the composite with a 1% addition of V2O5 performed better in the trial. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of adding Mn to a 0.5%Cu-added A356 alloy on the interfacial layer formed between the alloy and cast iron in compound casting. The results showed that the interfacial compounds layer thickness and the types of phases constituting the layer were significantly influenced by the addition of Mn. Microstructural analysis of the interface revealed an increase in interlayer thickness with the addition of 0.3%Mn. Moreover, the almost absence of Al4.5FeSi phase in the interfacial layer, which is typically observed close to aluminum region, was noted when Mn was added. Instead, the formation of Al(Fe,Mn)Si phase containing Mn was observed with the addition of 0.3%Mn. The Mn-rich phase was identified as cubic-Al(Fe,Mn)Si phase through TEM analysis. Additionally, comparing the nanoindentation hardness of the interfacial compounds layer of the Mn-added alloy with that of the base alloy (0.5%Cu-added A356) showed that the hardness near the aluminum region was relatively higher in the Mn-added alloy. [ABSTRACT FROM AUTHOR]

The evolution of eutectic Si morphology and microsegregation during homogenization heat treatment at 753K was examined for Al-Si-Cu-Mg-Ni alloy casting billets. Subsequently, casting billets homogenized at 753K for 0 s, 7.2 ks, and 28.8 ks were forged, and microstructures and mechanical properties at 473 and 573K were investigated for the forgings with different sizes of eutectic Si. Spheroidization of eutectic Si and elimination of microsegregation were achieved during the heating process of homogenization heat treatment. The spheroidized eutectic Si then coarsened with the homogenization heat treatment time. The interparticle spacing of the eutectic Si and constituent particles after the forging process increased with the coarsening of Si particles during homogenization heat treatment. In the tensile test at 473 K, the 0.2% proof stress, ultimate tensile strength (UTS), and elongation of the forgings were almost the same regardless of the homogenization heat treatment time, i.e., the size of eutectic Si. On the other hand, forgings made of a billet with a shorter homogenization heat treatment time showed more pronounced work-hardening behavior and higher 0.2% proof stress and UTS at 573 K. The increase in strength was explained by the enhancement of workhardening associated with the decrease in interparticle spacing, which depends on the Si particle size after homogenization heat treatment. [ABSTRACT FROM AUTHOR]

Unmodified hypoeutectic silumins have a microstructure composed of large-sized phases, which are the reason for their low mechanical properties. Many years of research have shown the modifying effects of many chemical elements and their compounds, including the master alloy consisting of Al-Ti-B, often in the form of the finished AlTi5B alloy. In this work, it was decided to check how the proportions of Ti and B content in the Al or AlSi-based master alloy affect the microstructure and mechanical properties of a hypoeutectic silumin, AlSi7Mg. It has been shown that a master alloy containing silicon (with the participation of Al + Ti + B) has a more effective impact on the refinement of the microstructure, and thus an increase in the mechanical properties of the AlSi7Mg alloy, than a master alloy without silicon. It has been shown that the ratio of titanium to boron content in the very-often-used AlTi5B modifier is not always optimal. It has been shown that the use of a master alloy with a composition similar to that of modified silumin with titanium and boron in a 2:1 ratio allows the obtaining of an AlSi7Mg alloy with higher mechanical properties than the alloy after the modification of the AlTi5 master alloy. [ABSTRACT FROM AUTHOR]

The printability of Al6SiMg0·5Er1·0Zr alloy at various laser power, scan speed, and hatch spacing was investigated. The optimal processing window was determined. The relationship between hatch spacing and lack of fusion (LOF) defects and microstructure is discussed. Hatch spacing significantly affects the cellular size, which is formed by eutectic Si network, and medium hatch spacing can achieve the finest microstructure. Samples with high densities and fine microstructures were investigated more carefully. The grain and cellular boundaries have many Al3(Er,Zr) phases. The grain size was refined to 2.64 μm, and the epitaxial growth of columnar crystals was completely suppressed. The cellular structure has been significantly improved. Get the equiaxed - ultrafine equiaxed - columnar multi-cellular structure with dramatically enhanced mechanical properties. The yield strength, tensile strength, and elongation were 373 Mpa, 480 MPa, and 5.5%, respectively. Grain boundary strengthening and Orowan strengthening was the main strengthening mechanisms.