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The present study investigates the effect of wall thickness on the mechanical properties of Al-5Mg-2.2Si-0.6Mn-0.1Ce castings, using squeeze casting to fabricate alloys with varying wall thicknesses. The results show that changes in wall thickness affect defect generation, grain size, and secondary dendrite arm space (SDAS), which in turn influence the tensile properties of the material. Specifically, the shrinkage porosity of the castings decreases gradually with increasing wall thickness, while the SDAS and grain size increase. Although this reduces defects and improves the tensile properties, the increase in SDAS and grain size leads to a decrease in yield strength and tensile strength. Notably, the material's tensile strength reaches its maximum (265.5 MPa) at a wall thickness of 10 mm. These findings demonstrate the importance of optimizing wall thickness parameters for complex castings, with potential implications for industrial production and application. [ABSTRACT FROM AUTHOR]

The hot compression simulation testing machine was utilized to conduct compression experiments on an Al-Mg-Si-Mn alloy containing the rare earth element Sc at a deformation temperature ranging from 450 to 550 °C and a strain rate of 0.01 to 10 s−1. The study focused on the hot deformation behavior of the aluminum alloy, resulting in the determination of the optimal range of deformation process parameters for the alloy. The relationship between material flow stress, deformation temperature, and strain rate was described using the Arrhenius relationship containing thermal activation energy based on the stress-strain curve of hot compression deformation of aluminum alloy. This led to calculations for structural factor A, stress index n, and stress level parameters as well as thermal deformation activation energy to establish a constitutive Formula for hot deformation rheological stress of aluminum alloy and calculate the power dissipation factor η. Through this process, an optimized range for the optimal deformation process parameter for aluminum alloy was determined (deformation temperature: 490~510 °C; strain rate: 0.05 s−1) and verified in combination with mechanical properties and microstructure through hot extrusion deformation trial production.

In this study, the effect of Mg content on the microstructure and mechanical properties of the Al-xMg-2.0Si-0.6Mn alloy was investigated. The study aimed to investigate the optimal addition of Mg elements to improve the comprehensive performance of the alloy. The microstructure, phase composition and fracture morphology of the alloy were determined through OM, SEM, TEM and XRD analysis. With the increase of Mg content, the number of strengthening phases increases, which improves the comprehensive properties of the alloy. When the Mg content in an alloy exceeds 5%, the solubility of the Mg2Si phase in the matrix is reduced, and the development of the coarse Mg2Si phase limits the alloy's elongation. The performance is excellent when the content of Mg is 5%. The alloy has maximum tensile strength, yield strength, and elongation of 227.22 MPa, 136.55 MPa, and 7.24%, respectively. Furthermore, we discovered that the point-like Mg2Si phase exists in the alloy and coexists with the point-like α-Al15(Fe, Mn)3Si2. TEM investigation revealed the incoherent relationship between the two point-like phases, and the phase diagram suggested α-Al15(Fe, Mn)3Si2 as a probable substrate for the nucleation of the Mg2Si phase.

The combined effect of temperature and humidity on the fracture toughness of aluminium alloys has not been extensively studied, and little attention has been paid due to its complexity, understanding of its behaviour, and difficulty in predicting the effect of the combined factors. Therefore, the present study aims to address this knowledge gap and improve the understanding of the interdependencies between the coupled effects of temperature and humidity on the fracture toughness of Al–Mg–Si–Mn alloy, which can have practical implications for the selection and design of materials in coastal environments. Fracture toughness experiments were carried out by simulating the coastal environments, such as localised corrosion, temperature, and humidity, using compact tension specimens. The fracture toughness increased with varying temperatures from 20 to 80 °C and decreased with variable humidity levels between 40% and 90%, revealing Al–Mg–Si–Mn alloy is susceptible to corrosive environments. Using a curve-fitting approach that mapped the micrographs to temperature and humidity conditions, an empirical model was developed, which revealed that the interaction between temperature and humidity was complex and followed a nonlinear interaction supported by microstructure images of SEM and collected empirical data. [ABSTRACT FROM AUTHOR]

The effect of Ce in amount of 0–0.5 wt.% on the microstructure and mechanical properties of the squeeze-cast Al–5Mg-2.2Si-0.6Mn alloys produced by squeeze casting technique was explored. The microstructure was observed by optical microscopy and scanning electron microscopy. The hardness and mechanical properties of the alloys were measured by Vickers hardness and tensile test. The microstructure of the squeeze-cast Al–5Mg-2.2Si-0.6Mn alloys is composed mainly of α-Al, Al–Mg2Si eutectic cells, the bulky lath-shaped Al8CeMn4 phase, Al2Mn3 and Al5Mn2Si5 phases after Ce is added. The results show that the addition of Ce leads to the grain refinement, which can improve the mechanical properties. When adding superfluous Ce, the formation of coarse and brittle Al8CeMn4 phase seriously reduces the mechanical properties of the alloy. With the increase of Ce content, the secondary dendrite arm spacing of different alloys decreases first and then increases, hence the hardness and tensile properties increase first and then decrease. The most remarkable improvement in the mechanical properties was acquired in the alloy with 0.10 wt.% Ce addition, the hardness reaches 48.1 HV, the ultimate tensile strength, yield strength and elongation are 265.5 MPa, 185.8 MPa and 5.8%, respectively.

The combined effect of temperature and humidity on the fracture toughness of aluminium alloys has not been extensively studied, and little attention has been paid due to its complexity, understanding of its behaviour, and difficulty in predicting the effect of the combined factors. Therefore, the present study aims to address this knowledge gap and improve the understanding of the interdependencies between the coupled effects of temperature and humidity on the fracture toughness of Al–Mg–Si–Mn alloy, which can have practical implications for the selection and design of materials in coastal environments. Fracture toughness experiments were carried out by simulating the coastal environments, such as localised corrosion, temperature, and humidity, using compact tension specimens. The fracture toughness increased with varying temperatures from 20 to 80 °C and decreased with variable humidity levels between 40% and 90%, revealing Al–Mg–Si–Mn alloy is susceptible to corrosive environments. Using a curve-fitting approach that mapped the micrographs to temperature and humidity conditions, an empirical model was developed, which revealed that the interaction between temperature and humidity was complex and followed a nonlinear interaction supported by microstructure images of SEM and collected empirical data.

The hot compression simulation testing machine was utilized to conduct compression experiments on an Al-Mg-Si-Mn alloy containing the rare earth element Sc at a deformation temperature ranging from 450 to 550 °C and a strain rate of 0.01 to 10 s -1 . The study focused on the hot deformation behavior of the aluminum alloy, resulting in the determination of the optimal range of deformation process parameters for the alloy. The relationship between material flow stress, deformation temperature, and strain rate was described using the Arrhenius relationship containing thermal activation energy based on the stress-strain curve of hot compression deformation of aluminum alloy. This led to calculations for structural factor A, stress index n, and stress level parameters as well as thermal deformation activation energy to establish a constitutive Formula for hot deformation rheological stress of aluminum alloy and calculate the power dissipation factor η. Through this process, an optimized range for the optimal deformation process parameter for aluminum alloy was determined (deformation temperature: 490~510 °C; strain rate: 0.05 s -1 ) and verified in combination with mechanical properties and microstructure through hot extrusion deformation trial production.

In the present work, we investigated the possibility of introducing fine and densely distributed α-Al(MnFe)Si dispersoids into the microstructure of extruded Al-Mg-Si-Mn AA6082 alloys containing 0.5 and 1 wt % Mn through tailoring the processing route as well as their effects on room- and elevated-temperature strength and creep resistance. The results show that the fine dispersoids formed during low-temperature homogenization experienced less coarsening when subsequently extruded at 350 °C than when subjected to a more typical high-temperature extrusion at 500 °C. After aging, a significant strengthening effect was produced by β″ precipitates in all conditions studied. Fine dispersoids offered complimentary strengthening, further enhancing the room-temperature compressive yield strength by up to 72–77 MPa (≈28%) relative to the alloy with coarse dispersoids. During thermal exposure at 300 °C for 100 h, β″ precipitates transformed into undesirable β-Mg2Si, while thermally stable dispersoids provided the predominant elevated-temperature strengthening effect. Compared to the base case with coarse dispersoids, fine and densely distributed dispersoids with the new processing route more than doubled the yield strength at 300 °C. In addition, finer dispersoids obtained by extrusion at 350 °C improved the yield strength at 300 °C by 17% compared to that at 500 °C. The creep resistance at 300 °C was greatly improved by an order of magnitude from the coarse dispersoid condition to one containing fine and densely distributed dispersoids, highlighting the high efficacy of the new processing route in enhancing the elevated-temperature properties of extruded Al-Mg-Si-Mn alloys.

The effects of different heating rates to a homogenisation temperature on the semisolid microstructure of Al–Mg–Si–Mn alloys are investigated. It is found that the size, morphology and distribution of the α-Al12Mn3Si2 intermetallic compound (Mn containing dispersoid) depend on the heating rate in the homogenisation process. Fine spherical and homogeneously distributed Mn containing dispersoid particles are found in the slow heated samples (07°C min-1), while inhomogeneously distributed coarser particles with a rod-like shape are found in the rapid heated samples (110°C min-1). The homogenised sample is deformed by 60% cold rolling. It is found that the recrystallised and semisolid grain sizes of the rapid heated sample are smaller than those of the slow heated sample in all conditions. Compared with the M4 alloy (04 mass-%Mn), the M7 alloy (072 mass-%Mn) has much finer semisolid grain size and smaller values of the shape factor close to 1. The Mn containing dispersoid greatly affects the semisolid grain size of the alloys. The results in this work show that the rapid heating in the homogenisation process is useful to produce high quality semisolid products of the Al–Mg–Si–Mn alloys. [ABSTRACT FROM AUTHOR]

In the present work, we investigated the possibility of introducing fine and densely distributed α-Al(MnFe)Si dispersoids into the microstructure of extruded Al-Mg-Si-Mn AA6082 alloys containing 0.5 and 1 wt % Mn through tailoring the processing route as well as their effects on room- and elevated-temperature strength and creep resistance. The results show that the fine dispersoids formed during low-temperature homogenization experienced less coarsening when subsequently extruded at 350 °C than when subjected to a more typical high-temperature extrusion at 500 °C. After aging, a significant strengthening effect was produced by β″ precipitates in all conditions studied. Fine dispersoids offered complimentary strengthening, further enhancing the room-temperature compressive yield strength by up to 72–77 MPa (≈28%) relative to the alloy with coarse dispersoids. During thermal exposure at 300 °C for 100 h, β″ precipitates transformed into undesirable β-Mg2Si, while thermally stable dispersoids provided the predominant elevated-temperature strengthening effect. Compared to the base case with coarse dispersoids, fine and densely distributed dispersoids with the new processing route more than doubled the yield strength at 300 °C. In addition, finer dispersoids obtained by extrusion at 350 °C improved the yield strength at 300 °C by 17% compared to that at 500 °C. The creep resistance at 300 °C was greatly improved by an order of magnitude from the coarse dispersoid condition to one containing fine and densely distributed dispersoids, highlighting the high efficacy of the new processing route in enhancing the elevated-temperature properties of extruded Al-Mg-Si-Mn alloys. [ABSTRACT FROM AUTHOR]