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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., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

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.

The laser powder bed fusion (L-PBF) process provides the cellular microstructure (primary α phase surrounded by a eutectic Si network) inside hypo-eutectic Al-Si alloys. The microstructure changes to the particle-dispersed microstructure with heat treatments at around 500 °C. The microstructural change leads to a significant reduction in the tensile strength. However, the microstructural descriptors representing the cellular and particle-dispersed microstructures have not been established, resulting in difficulty in terms of discussion regarding the structure-property relationship. In this study, an attempt was made to analyze the microstructure in L-PBF-built and subsequently heat-treated Al-12Si (mass%) alloys using the persistent homology, which can analyze the spatial distributions and connections of secondary phases. The zero-dimensional persistent homology revealed that the spacing between adjacent Si particles was independent of Si particle size in the as-built alloy, whereas fewer Si particles existed near large Si particles in the heat-treated alloy. Furthermore, the first principal component of a one-dimensional persistent homology diagram would represent the microstructural characteristics from cellular to particle-dispersed morphology. These microstructural descriptors were strongly correlated with the tensile and yield strengths. This study provides a new insight into the microstructural indices describing unique microstructures in L-PBF-built alloys.

Environmentally harmful silicon cutting waste (SCW) generated during the production of silicon solar cells possesses a high reuse value. However, the presence of oxide surface and impurities restrict the Si-cores reuse. Herein, inspired by the structure and composition of SCW, designed a combined process consisting of vacuum sintering and alloying to reuse SCW into Al-Si alloy at a low cost. Vacuum sintering promotes the reduction of the oxide surface by Si-core. Oxygen content was decreased by 92.54 %, demonstrating the successful removal of the oxide surface. The discharge of reduction products contributes to the densification, and the Si-core has converged into dense Vac-ceramic (Si block), rendering a relative density of 96.17 %. More importantly, during the alloying process, the formation of Vac-ceramic dredges the mass transfer pathway from Si-core to Al melt. As a result, the Si utilization rate increased about seven times compared with the direct reuse of pristine SCW. Compared with commercial Al-Si alloys, the Al-Si alloys prepared by reusing silicon cutting waste in this work have satisfactory mechanical properties. The method has the prominent advantages of being protective-atmosphere-free, additive-free, and scalability, and may be a promising candidate for the silicon cutting waste purifying and reusing field., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The goal of this research was to determine how the master alloys Al-5Ti-0.25C-0.25B and Al-5Ti-1B affected the mechanical properties and structural characteristics of the alloy Al-9.5Si-1.5Cu-0.8Mn-0.6Mg. Field emission scanning electron microscopy (FE-SEM) was used to probe the microscopic composition, and the mechanical properties were evaluated using tensile testing. The results showed that, by adding 0.5% Al-5Ti-0.25C-0.25B master alloy and 0.5% Al-5Ti-1B master alloy, the α-Al dendrites can be significantly refined. In the extrusion state, the ultimate tensile strength and elongation with 0.5% Al-5Ti-0.25C-0.25B master alloy reached 380 MPa and 11.2%, which were 5.5% and 22.4% higher than no refinement, respectively. The elongation of the samples with the Al-5Ti-1B alloy addition increased from 9% to 11.9%, which is attributed to the fact that more pronounced complete recrystallization occurred during the extrusion heat treatment.

Improving the engineering properties of Al-7Si cast alloys (300 series) provides an attractive alternative to automotive and aircraft engine industries. The solubility limit of silicon (Si) in Al contributes to the precipitation of flake-shaped Si particles with sharp edges, which function as a stress riser and promote crack propagation during the eutectic phase while also weakening the protective layer's durability. In this study, the impact of microstructure refinement of Al-7Si alloys by using cooling slope, thixoforming and the T6 heat treatment process on hardness and corrosion resistance behavior was investigated. Results showed that the microstructures of the as-cast alloy had a very coarse dendritic shape, whereas the dendritic transferred to the globular α-Al phase, and the Si particles were replaced into a lamellar- or acicular-like shape after the cooling slope and thixoforming process, respectively. The as-cast, cooling slope and thixoformed samples were subjected to the T6 heat treatment process, which enhanced the hardness to 79, 99 and 104 HV, respectively, due to Si particle refinement. The potentiodynamic test revealed that the corrosion rate dropped to 0.00790 and 0.00736 mmpy -1 in the heat-treated cooling slope and thixoforming samples. This finding can be attributed to the substantially refined Si particles and reduced eutectic phase area due to the smaller cathodic to anodic area ratio.

Silicon cutting waste (SCW) generated during Si wafers producing process can be recycled by AlSi alloying process. However, the presence of O in SCW has a detrimental impact on recycling process. In this study, cryolite was introduced to eliminate the hindrance of O. The influences of smelting temperature and the amount of cryolite additive on the yield of the blocky AlSi alloys and the Si recovery ratio of the SCW have been investigated and the alloying conditions were optimized to a smelting temperature of 1000 °C and a cryolite/SCW mass ratio of 0.8, achieving a AlSi alloys yield of 95.99% and a Si recovery ratio of 84.77%, which were far greater than those without cryolite additive. The results showed that the addition of cryolite additive can effectively improve the smelting effect and reduce the alloying temperature. Furthermore, the action mechanism of cryolite in Al-SCW system was analyzed, and the results revealed that the molten cryolite can dissolve the generated Al 2 O 3 existing on the surface of AlSi alloy droplets and finally contributes to the aggregation of these droplets. This method has advantages including high Si recovery ratio of SCW, low alloying temperature and simple technological process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Large amounts of Ti-bearing blast furnace slag (TBFS), diamond wire saw Si powder (DWSSP), and Al alloy scrap (AAS) are generated annually. Although these are industrial waste, they contain valuable Ti, Si, and Al resources. In this work, a novel process is developed for the simultaneous recycling of Ti, Si, and Al from these three wastes to prepare TiSi 2 and Al-Si alloys. TBFS, DWSSP, and CaO (flux) were mixed to form a mixed Ti-Si-slag, which was combined with AAS and underwent reduction smelting at 1823 K to prepare Si-Ti-Al alloys. Subsequently, TiSi 2 (98.7%) and low-Fe Al-Si (0.64 wt% Fe) alloys were prepared sequentially by separating the molten Si-Ti-Al melt via electromagnetic directional crystallization with a pull-down rate of 3 µm/s. The impurities in the Si-Ti-Al alloy were removed during the separation process by segregation at the boundary of the solid-liquid phase and volatilization. Furthermore, the entire process produces no waste acid or waste gas. Therefore, this work has introduced an efficient and environmentally friendly method for the value-added recycling of Ti, Si, and Al resources from accumulated TBFS, DWSSP, and AAS., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Duplex nucleation and its effect on the grain size and properties of near eutectic Al-Si alloys were investigated in this work. It is found that the grain size of Al-13Si-1Cu alloy can be greatly refined by addition of Al-2Ti-0.5B-0.5C and Al-P master alloys, and TiB 2 /AlP duplex nucleation was observed at the nuclei of primary silicon in the process of studying the refinement mechanism. TiB 2 phase coated by Al co-existed with AlP in the nuclei of primary Si. The existence of Al phase should not only guarantee the promotion of TiB 2 particles on the nucleation of AlP particles, but also made TiB 2 particle stable in the core of primary silicon through the interaction with the Si phase. Duplex nucleation can not only affect the grain size of Al-Si alloy, but also effect of the distribution of strengthening phases in Al-Si alloy and improve the properties. Compared with single Al-P master alloy treatment, the tensile strength of Al-12Si-4Cu-2Ni-1Mg alloy after duplex nucleation treatment are improved obviously. The fatigue performance of Al-12Si-4Cu-2Ni-1Mg alloy is also improved significantly by the duplex nucleation.

Constantly growing requirements concerning the quality of poured machinery components give rise to the need to find new solutions to improve their mechanical and technological properties, considering economic and ecological aspects resulting from energy consumption of the casting and heat treatment processes. This study presents the investigation of the effect of heat treatment on mechanical properties (tensile strength R m , elongation A 5 , hardness HBW ) of the AlSi7Mg alloy without modification and modified with strontium. Obtained results allowed us to determine T6 heat treatment parameters associated with the improvement of mechanical properties of the alloy with simultaneous limitation of duration of solutioning and aging treatments. The maximum increase in R m was 67%, and 55% in the case of HBW , with a slight decrease in elongation (approx. 10%) in relation to an alloy not subjected to heat treatment in the adopted scope of tests for the total time of heat treatment of 4-6 h. The increase in elongation of up to 250% requires aging at a temperature exceeding 300 °C, which also causes a decrease in durability and hardness by 20%. Modification of the alloy using strontium before heat treatment facilitates the process of fragmentation and balling of silicone precipitates.

The microstructural and wear properties of laser-cladding WC/Ni-based layer on Al-Si alloy were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and wear-testing. The results show that, compared with the original specimen, the microhardness and wear resistance of the cladding layer on an Al-Si alloy were remarkably improved, wherein the microhardness of the layer achieved 1100 HV and the average friction coefficient of the layer was barely 0.14. The mainly contributor to such significant improvement was the generation of a WC/Ni-composite layer of Al-Si alloy during laser cladding. Two types of carbides, identified as M 7 C 3 and M 23 C 6 , were found in the layer. The wear rate of the layer first increased and then decreased with the increase in load; when the load was 20 N, 60 N and 80 N, the wear rate of layer was1.89 × 10 -3 mm 3 ·m -1 , 3.73 × 10 -3 mm 3 ·m -1 and 2.63 × 10 -3 mm 3 ·m -1 , respectively, and the average friction coefficient (0.14) was the smallest when the load was 60 N.

Large amounts of silicon cutting waste (SCW) are generated during Si wafers producing process. In this paper, SCW was mixed with Al powder to prepare Al-Si alloys by a one-step smelting process in corundum crucibles. The influences of smelting temperature (1000 °C, 1200 °C and 1500 °C) on the products of each zone (surface layer zone, loose granular zone and blocky products zone) were investigated. Al-Si alloys in the form of granular and blocky were prepared and the blocky Al-Si alloys mainly concentrated in the blocky products zone. The increase of smelting temperature can promote the aggregation of Al-Si alloy particles. The yields of Al-Si alloy blocks obtained at 1000 °C, 1200 °C and 1500 °C were 0%, 58% and 69%, respectively. The Si contents of Al-Si alloy blocks at 1200 °C and 1500 °C were 15.8 wt% and 17.1 wt% respectively. After compacting the raw materials, the yields of the blocky Al-Si alloys obtained at 1000 °C, 1200 °C and 1500 °C were increased to 65%, 72% and 79% and the corresponding Si contents of the blocky Al-Si alloys were increased to 16.0 wt%, 16.5 wt% and 17.3 wt% respectively. The reaction mechanism of the alloying process was also investigated., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The paper presents the results of study concerning the evaluation of the precipitation hardening parameters (temperatures and times of solution treatment and artificial ageing processes) having an effect on mechanical properties, and the change in the microstructure of the EN AC-AlSi11(Fe) alloy. Based on the obtained results and performed statistical analysis, regression equations and the response surface model in the form of spatial and contour plots were determined to illustrate the effects of solution treatment and artificial ageing parameters on the mechanical properties of the investigated alloy. The performed heat treatment had a positive effect on improving the mechanical properties of the alloy versus the initial state. The maximum increase in tensile strength was by 52%, in unit elongation by 56%, in Brinell hardness by 44% and impact strength by 88%. Furthermore, a favorable change was observed in the microstructure of the investigated alloy, especially regarding eutectic silicon precipitations, which underwent partial spheroidization and coagulation after the heat treatment.

The thermal stability of the Al-Si alloys during the thermal exposure process from 250 °C to 400 °C was systematically investigated. The relationships between the morphological evolution and the mechanical changes of the alloys were determined through the Vickers hardness test and materials characterization method. Initially, the alloys exhibited similar thermal degradation behavior. For example, the exposure process of the alloy at 300 °C can be divided into two stages according to the changes of the alloy hardness and the matrix micro-hardness. In detail, the first stage (0-2 h) exhibited a severe reduction of the alloy hardness while the second stage showed a more leveled hardness during the following 98 h. There are three identified morphological characteristics of Ni-rich phases in the alloy. Furthermore, the differences in both composition and the micro-hardness between these Ni-rich phases were confirmed. The underlying relationships between the morphological transformation of the Ni-rich phases and hardness fluctuation in the alloy were correlated and elucidated. The observed alloy hardness increase when the exposure temperature was 400 °C was unexpected. This behavior was explained from the perspectives of both Ni-rich phases evolution and dispersoid formation.

The WCCo/PCD (Diamond Dispersed Cemented Carbide-DDCC) manufactured with the use of PPS (pulse plasma sintering) are modern materials intended for cutting tools with the benefits of tungsten carbides and polycrystalline diamonds. Nevertheless, the cutting performance of DDCC materials are currently not recognized. Thus this study proposes the evaluation of technological effects of a precise groove turning process of hard-to-cut AlSi13MgCuNi alloy with DDCC tools. The conducted studies involved the measurements of machined surface topographies after grooving with different cutting parameters. In addition, the tool life and wear tests of DDCC inserts were conducted during grooving process and the obtained results were compiled with values reached during machining with cemented carbide tools. It was also proved that grooving of AlSi13MgCuNi alloy with DDCC inserts enables 5 times longer tool life and almost 3-fold increase of cutting path compared to values obtained during grooving with H3 and H10 cemented carbide inserts. Ultimately, the feed value of f = 0.15 mm/rev and cutting speed in a range of 800 m/min ≤ v c ≤ 1000 m/min during grooving with DDCC inserts can be defined as an optimal machining parameters, enabling the maximization of tool life and improvement in surface quality.

Separation of refined silicon from Al-Si melt is still a puzzle for the solvent refining process, resulting in considerable waste of acid and silicon powder. A novel modified Czochralski method within the Al-Si alloy is proposed. After the modified Czochralski process, a large amount of refined Si particles was enriched around the seed crystalline Si and separated from the Al-Si melt. As for the Al-28%Si with the pulling rate of 0.001 mm/min, the recovery of refined Si in the pulled-up alloy (PUA) sample is 21.5%, an improvement of 22% compared with the theoretical value, which is much larger 1.99 times than that in the remained alloy (RA) sample. The content of impurities in the PUA is much less than that in the RA sample, which indicates that the modified Czochralski method is effective to improve the removal fraction of impurities. The apparent segregation coefficients of boron (B) and phosphorus (P) in the PUA and RA samples were evaluated. These results demonstrate that the modified Czochralski method for the alloy system is an effective way to enrich and separate refined silicon from the Al-Si melt, which provide a potential and clean production of solar grade silicon (SoG-Si) for the future industrial application.

A wrought Al-11.3Si-0.6Mg alloy under hot extrusion (T1), solution treatment (T4), and solution treatment + artificial aging (T6) states were friction stir welded at welding speed of 100 mm/min and rotation rate of 800 rpm. The effect of prior heat-treatment on the microstructure and mechanical properties of the welds were investigated. The results show that the microstructures of the nugget zones have little dependence on the initial states of the base material. In the nugget zones, complete recrystallized structures with equaxied grains in the Al matrix were formed under all conditions. The Si particles in the nugget zones are almost unchanged compared with those of their base materials (BMs) in the three states. In contrast, the joint efficiency of the obtained welds was very sensitive to the initial material condition. The joint efficiency under the T1 state is more than 90% due to the fact that the microstructure is almost unchanged, except for the slight coarsening of the Al matrix grains and some of the Mg 2 Si phases during the friction stir welding process. However, the joint efficiency in the T4 and T6 conditions is only 77.22% and 62.03%, respectively. The relatively low weld strength in the T4 and T6 conditions is due to the elimination of the solid solution strengthening and age hardening effects during friction stir welding. The hardness distributions along the cross section of joints are all W-shaped under T1, T4, and T6 conditions., Competing Interests: The authors declare no conflict of interest.

In this paper, the effect of the equal-channel-angular-pressed (ECAPed) substrate on the coating formation and anticorrosion performance of the anodized Al-11Si alloy was systematically investigated. The ECAP process dramatically refines both Al and Si phases of the alloy. The parallel anodizing circuit is designed to enable a comparative study of anodizing process between the cast and the ECAPed alloys by tracking their respective anodizing current quota. The optimum coatings of both alloys were obtained after anodization for 30 min. The ECAPed alloy attained a thicker, more compact, and more uniform coating. Energetic crystal defects in the fine Al grains of the ECAPed substrate promote the anodizing reaction and lead to the thicker coating. Fragmented and uniformly distributed fine Si particles in the ECAPed alloy effectively suppress the coating cracks, enhancing the compactness of the coating. Overall, the ECAP-coated sample exhibits the best anticorrosion performance, which is evidenced by the concurrently enhanced prevention of coating and improved corrosion resistance of the substrate., Competing Interests: The authors declare no conflict of interest.

Understanding the Si segregation behavior in hypereutectic Al-Si alloys is important for controlling the micro- and macrostructures of ingots. The macrosegregation mechanism and morphological evolution of the primary Si phase were investigated during electromagnetic directional solidification (EMDS). Both numerical simulations and experimental results strongly suggested that the severe macrosegregation of the primary Si phase was caused by fluid flow and temperature distribution. Microscopic analysis showed that the morphological evolution of the Si crystal occurred as follows: planar → cellular → columnar → dendritic stages during EMDS. Based on constitutional supercooling theory, a predominance area diagram of Si morphology was established, indicating that the morphology could be precisely controlled by adjusting the values of temperature gradient ( G ), crystal growth rate ( R ), and solute concentration ( C ₀). The results provide novel insight into controlling the morphologies of primary Si phases in hypereutectic Al-Si alloys and, simultaneously, strengthen our understanding of the macrosegregation mechanism in metallic alloys.

In this research, various processing conditions were implemented to enhance the mechanical properties of Al-Si alloys. The silicon content was varied from hypoeutectic (Si-10 wt.%) to eutectic (Si-12.6 wt.%) and hypereutectic (Si-14 wt.%) for the preparation of Al-XSi-3Cu-0.5Fe-0.6 Mg (X = 10⁻14%) alloys using die casting. Subsequently, these alloys were hot-extruded with an optimum extrusion ratio (17:1) at 400 °C to match the output extruded bar to the compressor size. An analysis of the microstructural features along with a chemical compositional analysis were carried out using scanning electron microscope along with energy dispersive X-ray spectroscopy and transmission electron microscope. The SEM micrographs of the extruded samples displayed cracks in primary Si, and the intermetallic (β-Al₅FeSi) phase was fragmented accordingly. In addition, the silicon phase was homogenously distributed, and the size remained constant. The mechanical properties of the extruded samples were enhanced by the increase of silicon content, and consequently the ductility decreased. By implementing proper T6 heat treatment parameters, coherent Al₂Cu phases were formed in the Al matrix, and the Si phase was gradually increased along with the silicon content. Therefore, high tensile strength was achieved, reaching values for the Al-XSi-3Cu-0.5Fe-0.6Mg (X = 10⁻14%) alloys of 366 MPa, 388 MPa, and 420 MPa, respectively.

In this article, the anti-poison performance of novel Al-6Y-2P master alloy for impurity Ca in hypereutectic Al-Si alloys was investigated in detail. According to the microstructural analysis, it can be found that the primary Si and eutectic Si particles could be relatively modified and refined. In order to investigate the influence mechanism of Ca on the limited refinement performance of Al-6Y-2P master alloy, types of Al-xSi-2Ca-3Y-1P (x = 0, 6, 12, 18, and 30) alloys were prepared. It is observed that Ca takes the form of more stable Ca3P2 compounds by reacting with YP, and the surface of Ca3P2 particles are unsmooth, and even some have wrinkles in Al Al-2Ca-3Y-1P alloy. With the increase of Si content in Al-xSi-2Ca-3Y-1P (x = 6, 12, 18 and 30) systems, the multi-encapsulation structures, i.e., the phosphide (AlP and YP), hexagonal Al2Si2Ca, the Al3Si2Y2 or primary Si from inside to outside in order were examined.The excapsulation of YP and AlP caused by Al2Si2Ca might be the reason for the limited refinement effect of Al-6Y-2P master alloy for hypereutectic Al-18Si alloys., Competing Interests: The authors declare no conflict of interest.

The migration of primary Si grains during the solidification of Al-18 wt%Si alloy under a high-gradient magnetic field has been investigated experimentally. It was found that under a gradient magnetic field, the primary Si grains migrated toward one end of the specimen, forming a Si-rich layer, and the thickness of the Si-rich layer increased with increasing magnetic flux density. No movement of Si grains was apparent under a magnetic field below 2.3 T. For magnetic fields above 6.6 T, however, the thickness of the Si-rich layer was almost constant. It was shown that the static field also played a role in impeding the movement of the grains. The primary Si grains were refined in the Si layer, even though the primary silicon grains were very dense. The effect of the magnetic flux density on the migratory behavior is discussed.