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This study aims to explore the influence of control parameters from the perspective of the amorphous ceramic coating formation process. Three preparation processes were preferred based on the thickness, appearance and corrosion resistance of the coatings by orthogonal experiment. The surface morphology, cross-sectional structure, phase composition and micro-hardness of PEO coatings were examined using scanning electron microscopy (SEM)/Energy dispersive X-ray spectroscopy (EDS), X-ray diffractometry (XRD) and hardness measurement techniques. Findings indicate that voltage exerts the most significant impact on coating thickness and appearance, whereas the influence of other parameters becomes more pronounced as the voltage increases. Three amorphous ceramic coatings prepared in 20 min with thicknesses of 27.4 μm, 83.2 μm and 193.3 μm increased the surface hardness of 6061 aluminium alloy by 6–8 times, and decreased the corrosion current density of 6061 aluminium alloy by 3 orders of magnitude in 1 mol L−1 HCl solution. Moreover, the thickening of the coating primarily occurs within a few minutes after the voltage reaches its peak, and high frequency and low duty ratio are prerequisites for better appearance under higher voltage conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

This study presents the development of a material selection decision support system for an automotive rooftop tent. The system uses five parameters of material cost, formability, corrosion resistance, tensile strength and hardness to optimize material choice from a list of aluminium alloy options. This was done before production via the deep drawing process can commence. The parameters were quantified using the average market prices for each alloy, product requirements obtained from the case study and the performance data that was obtained from the uniaxial tensile and hardness tests. These inputs were combined with the developed material selection framework and then programmed into a web-based decision support system for automated, data-driven material selection. The output presents the recommendation for the optimum material that balances cost-effectiveness and performance. The decision support system was successfully used to select the optimum alloy for the rooftop tent. Results show that AA1050 is the optimum material, providing weight reduction at the minimum achievable cost without compromising the product requirements for the rooftop tent. The decision support system is also scalable, and this allows it to be used with larger datasets for different products and processes in the future. [ABSTRACT FROM AUTHOR]

Nowadays, with the development of electromobility, the requirements not only for the mechanical properties but also for the thermal conductivity of castings are increasing. This paper investigates the influence of casting and heat treatment technology on the thermal diffusivity and thermal conductivity of an AlSi10MnMg alloy. The thermal diffusivity was monitored as a function of temperature in the range of 50–300 °C for the material cast by high-pressure die casting (HPDC) and also by gravity sand casting (GSC) and gravity die casting (GDC). This study also investigated the effect of the T5 heat treatment temperature (artificial ageing without prior solution treatment—HT200, HT300, and HT400) on the thermal conductivity of the material cast by different technologies. Experiments confirmed that the thermal diffusivity or thermal conductivity of the alloy depends on the casting technology. The slower the cooling rate of the casting, the higher the thermal conductivity value. For the alloy in the as-cast condition, the thermal conductivity at 50 °C is in the range of about 125 to 138 [W·m−1·K−1]. Regardless of the casting method, the thermal conductivity tends to increase with temperature (50–300 °C). Furthermore, a positive effect of heat treatment without prior solution treatment (HT200, HT300, and HT400) on the thermal conductivity was demonstrated. Regardless of the casting method of the samples, the thermal conductivity also increases with increasing heat treatment temperature. The results further showed that when artificial ageing is performed in industrial practice on castings to increase mechanical properties in the temperature range of 160–230 °C, this heat treatment has a positive effect on thermal conductivity. [ABSTRACT FROM AUTHOR]

To meet the application requirements of electronic connectors, a trivalent chromium process (TCP) conversion coating was prepared on the Zn–Ni alloy plating of 2024 aluminium alloy. The composition of the TCP solution was as follows: 45 g/L Cr(NO3)3, 14 g/L CoCl2, 1.3 g/L NiCl2, 10 g/L citric acid, 10 g/L succinic acid and 1 g/L sodium dodecyl sulphate. The properties of TCP were characterised by a range of techniques, including macroscopic observations, scanning electron microscope, energy‐dispersive X‐ray spectrometer, three‐dimensional (3D) morphometry, electrochemical impedance spectroscopy, polarisation curves and conductivity tests. The TCP prepared in this experiment exhibits a uniform black colour and bright appearance, predominantly composed of Zn, Ni, O, Cr and Co. The TCP enhances the impedance of Zn–Ni alloys, reduces the corrosion current to 1.99 × 10−5 A/cm2 and maintains a flatter surface 3D morphology and less surface roughness following electrochemical testing. It has better corrosion resistance. Following the preparation of the TCP on a suitably sized shell sample, the shell resistance was 1.2 mVDC with good electrical conductivity, which meets the requirements for electrical connector applications. [ABSTRACT FROM AUTHOR]

As is widely known, the construction industry is one of the sectors with a large contribution to global carbon emissions. Despite numerous efforts in the construction industry to develop low-carbon materials, there is a limited number of studies quantifying and presenting the overall environmental impact when these materials are applied in a construction project as structural members. To address this gap, this study focuses on assessing the life-cycle performance of novel structural aluminium alloy–concrete composite columns. In this paper, the environmental impacts and economic aspects of a concrete-filled aluminium alloy tubular (CFAT) column and a concrete-filled double-skin aluminium alloy tubular (CFDSAT) column were assessed using life-cycle assessment (LCA) and life-cycle cost analysis (LCCA) approaches, respectively. The cradle-to-grave system boundary is considered for these analyses to cover the entire life-cycle. A concrete-filled steel tubular (CFST) column is also assessed for reference. All columns are designed to have the same load-carrying capacity and, thus, are compared on a level-playing basis. A comparison is also made of the self-weight of these columns. In particular, the self-weight of the CFST column is reduced by around 17% when the steel tube is replaced by an aluminium alloy tube, and decreased by 47% when the double-skin technique is adopted in CFDSAT columns. The LCA results indicate that the CO2 emission of CFST and CFAT is almost the same, which is 21% less than the CFDSAT columns due to the use of high aluminium in the latter. The LCCA results show that the total life-cycle cost of CFAT and CFDSAT columns is around 29% and 14% lower, respectively, than that of the CFST column. Finally, a sensitivity analysis was carried out to evaluate the effects of data and assumptions on the life-cycle performance of the examined columns. [ABSTRACT FROM AUTHOR]

This study focuses into strategizing the usage of self-reacting bobbin tool friction stir welding (SRBT-FSW) to obtain consistent microstructural homogeneity along the thickness of AA6061 aluminium alloy (AA) thick plates during welding. The SRBT-FSW technology, distinguished by its dual-shoulder design, represents a significant step forward in FSW by eliminating the requirement for a backing anvil and promoting balanced heat distribution. This study seeks to address the issues of maintaining uniform microstructural characteristics throughout the weld zone, which is crucial for the mechanical performance and durability of welded joints in structural applications. The experimental study entails the systematic welding of AA6061 plates of 6 mm thickness using a self-reacting bobbin tool under a fixed processing condition. Electron backscatter diffraction (EBSD) was used to characterize the grain structure and phase distribution over the weld. Mechanical parameters like as tensile strength and hardness were determined to establish correlations between microstructure and mechanical performance. The results demonstrated that SRBT-FSW significantly enhances microstructural homogeneity across the weld zone, leading to improved mechanical properties. In the Bottom Zone (BZ), a refined grain structure with an average grain size (AGS) of 3.53 µm and a random or weak texture was observed, contributing to enhanced hardness and mechanical performance, with an ultimate tensile strength (UTS) of 220 MPa. In contrast, the Top Zone (TZ) exhibited a coarser AGS of 4.33 µm with a pronounced {111} crystallographic texture, resulting in a slightly lower UTS of 205 MPa. The Middle Zone (MZ), influenced by the greater heat input from both the TZ and BZ, showed an intermediate AGS of 3.99 µm, predominantly oriented along the {101} plane, and achieved a UTS of 194 MPa, with a slight reduction in ductility. This study highlights the potential of self-reacting bobbin tool friction stir welding as a reliable method for making high-quality, homogeneous welds in thick aluminium plates and paving way for their wider application in the aerospace, automotive, and shipbuilding industries, where homogeneous microstructural qualities are of significant importance. [ABSTRACT FROM AUTHOR]

The water as a welding environment may generate serious technological and metallurgical problems but in certain cases, the physicochemical properties of water can be used effectively, e.g., to impart the specific properties of welded materials. The purpose of the work was verification of effectiveness of the water cooling of aluminium alloy AA5754 for various sets of technological parameters of underwater friction stir welding (UFSW). For the joints performed with the range of parameters of rotational speed: 475–925 rpm and welding speed: 47.5–95 mm/min, the following examinations were carried out: visual tests, radiographic tests, static tensile test, fractography (SEM, scanning electron microscope) analysis, and surface texture analysis performed with 3D measurement system. All of the joints were characterized with some amount of flash. Besides, depending on the values of selected parameters, the defects arising from inadequate stirring were found—tunnel defects and melting. The best appearance of the joint was obtained for the set of parameters of 925 rpm and 47.5 mm/min. The samples of the same joint were found to be of the highest mechanical properties—ultimate tensile strength (UTS) of 194 MPa and elongation (A) of 9.2%. The results were confirmed by the fractography analysis, which in this case indicated the ductile fracture mode. Dynamic plastic behaviour strongly depends on the process parameter values, which was reflected in the results of surface texture analysis. The parameter selection resulted in significant changes in the roughness results (from 8 to 14.2 µm depending on the sample) as well as the flow ring distance of the weld (from 20 to 50 µm depending on the sample). [ABSTRACT FROM AUTHOR]

Aluminium metal matrix composites are widely used in automotive, aerospace, marine, and structural engineering due to their high strength-to-weight ratio and superior mechanical properties. Optimizing friction stir process parameters is critical to enhancing the performance of these materials. This study investigates the effects of FSP parameters such as rotational speed, tilt angle, and traverse speed, on the mechanical properties of AA5083/Silicon carbide and AA5083/Coal composites. Using a Taguchi L9 design of experiments, signal-to-noise ratio, and analysis of variance, this study identifies the optimal process settings for maximizing ultimate tensile strength, microhardness, and elongation. From the results, the study revealed that for AA5083/Silicon carbide composites, rotational speed was the most significant factor affecting tensile strength, while for AA5083/Coal composites, tilt angle played a more critical role. Rotational speed consistently influenced microhardness and elongation for both materials. The signal-to-noise ratio analysis indicates that optimal FSP parameters vary depending on the reinforcement material used. This study highlights the importance of tailoring FSP settings to specific reinforcements to achieve optimal mechanical properties. These findings contribute to the advancement of friction stir processing techniques for fabricating high-performance aluminium metal matrix composites, particularly for applications in industries requiring strong, lightweight, and corrosion-resistant materials. [ABSTRACT FROM AUTHOR]

The micro-segregation in the as-cast AA6082 aluminium alloy were investigated across a range of length scales using a combination of analytical electron microscopes. It is found that the micro-segregation bands form an inter-connected network following grain boundaries and inter-dendritic channels. The micro-segregation can be divided into major micro-segregation and minor micro-segregation; the former is mainly on the grain boundaries consisting of iron-bearing intermetallic; the latter occurs both, along the grain boundaries and inter-dendritic channels, consisting mainly of Mg and Si alloying elements. The atomic-scale imaging reveals that in the minor-segregation bands, the supersaturated solute concertation has formed precipitates that had either nucleated heterogeneously on the dislocation network or homogeneously inside the aluminium matrix. The heterogeneously nucleated precipitates in the dislocation lines are composed of a mixture of phases down the precipitation sequence meanwhile, the homogenously grown ones are discrete phases that appear at the early stages of the precipitation sequence. [ABSTRACT FROM AUTHOR]

We have used CALPHAD-guided design methodology to develop a novel lightweight Al–Ti–Hf alloy with nearly 50 vol% in-situ formed trialuminide reinforcement. Through compositional optimization, Al87.5Ti6.25Hf6.25 (at%) was chosen as the experimental alloy composition. Using the Differential scanning calorimetry (DSC) and CALPHAD-derived melting point data, the as-cast alloy was subjected to 24 h homogenization heat treatment at 475 °C to achieve equilibrium. X-ray diffraction (XRD), Scanning electron microscopy (SEM), and DSC analyses revealed that the developed alloy has a dual-phase microstructure, composed of approximately 50 vol% of an FCC Al-rich matrix and 50 vol% of an Al3(Ti, Hf)-type (D022) phase, which matches closely with the thermodynamic calculations. The experimental onset melting point of the Al-rich matrix was determined to be 638 °C which is significantly higher than Al–Si-based high-temperature (HT) alloys, indicating the potential of the developed alloy as a HT structural material. Nanoindentation (NI) tests demonstrated the remarkable phase-specific nanomechanical properties of the alloy. The developed alloy possessed a microhardness of 3075 MPa, which not only surpasses 7075-Al, A390-Al alloys and CP-Ti, but also rivals the microhardness of Ti–6Al–4V alloy at nearly 18% lower density. The study highlights the potential of this novel alloy in applications that demand for materials with low density, high hardness, and superior wear resistance. [ABSTRACT FROM AUTHOR]

This study focused on optimizing the process of CNC machining to enhance productivity and product quality of surface finish Ra via the process parameters of the cutting speed (vc), feed rate (vf), and cutting depth (doc). Experimentation was performed on workpieces of AA-6061 to investigate the response Ra through variation of the process parameters to analyze their best fit using RSM with 2³ full factorial designs L-8 of DOE. The analysis of variance (ANOVA) was then used to find the major contributors among them that were responsible for the Ra. Based on the result, better Ra was obtained at 0.103 µm using the best fit of vf (150 mm/min), vc (220 m/min), and doc (0.1 mm). ANOVA shows vf contributed better Ra followed by vc and doc respectively. In addition, the level of Ra's was analyzed through contour plots represented by different colours. It continued to analyze the effect of the process parameters via the main effects plot, Pareto chart, and the contour plot in the predictive desirability model, which indicated that the plots and chart confirmed the vf had more influence compared to others. The study confirmed that the low-level parameters provided better Ra to be used for polishing. [ABSTRACT FROM AUTHOR]

Arc weaving is a feasible technique for making thick-walled components in the arc-based directed energy deposition process (DED-Arc). In the current study, four different arc weaving strategies, namely, triangle, square, semi-circle, and helix, are used to fabricate the walls. For this, gas tungsten arc welding (GTAW) based DED-Arc set-up using aluminium alloy wire (ER4043) as a filler material is used for different printing strategies. The fabricated walls were investigated for their surface characteristics, microstructure, mechanical properties and residual stress. The weld-bead and wall geometry study revealed that for the same number of layers, the semi-circular arc-weaving strategy had the maximum height among all, with an effective area of 65.77 %. The waviness of the side surface of the walls was maximum for the semi-circle (714 ± 35 µm), indicating the semi-circle will require almost twice the amount of machining than the helix, square, and triangle in postprocessing operation. The optical micrographs showed that the semi-circular weaving pattern exhibited a coarser gain with thicker grain boundaries with an average grain size of 46.4 ± 23.7 µm as compared to other weaving patterns. The triangle weaving pattern demonstrated the smallest grain size among all, resulting in high hardness and superior wear resistance. The residual stress (RS) results revealed that the RS is in tension (22–24 MPa) in the bottom layers for all the walls and becomes almost zero (−1.5 to −2.5 MPa) in the top layers except for the walls formed by helix strategy. The square weaving strategy strikes a balance between surface characteristics, microstructure, and mechanical properties, making it a highly viable option for thick wall fabrication. [Display omitted] [ABSTRACT FROM AUTHOR]

Spark plasma sintered, AA7050 reinforced with nano hexagonal boron nitride (n-h-BN) particles followed by characterisation research was carried out to determine the impact of h-BN in the aluminium matrix. With the aid of field-emission scanning electron microscopy , the uniform dispersion of hexagonal boron nitride was examined, and the impact of altering h-BN concentration on the mechanical and tribological properties was studied. In order to achieve individual dispersion of h-BN particles at low milling time without causing any structural damage, pre-mixing of powders prior to high-energy ball milling proved beneficial. Using the X-ray diffraction method, structural and phase analysis was performed on the powders as well as sintered samples. Pin-on disc apparatus is used for testing the weight loss of the composites. SEM was used to examine the worn surfaces of the substrate. According to the wear analysis, adding reinforcement with 0.5 wt% h-BN resulted in a 65% reduction in wear rate and a 33% increase in hardness. It has been found that h-BN tends to aggregate in composite powder above 0.5 wt%, reducing its physical and mechanical qualities. [ABSTRACT FROM AUTHOR]

Advanced manufacturing processes have increased industrial productivity and enhanced marketing prospects. Optimization techniques coupled with simulative methods in laser welding can immensely contribute to the development of the industries of the future. This work reports the research results emanating from the application of simulative techniques for the prediction of welding parameters of the laser welding process of aluminium alloy 2024. Numerical simulation was conducted in a proprietary software environment and subsequently, artificial neural network (ANN)-based simulation was conducted. The simulatively obtained data were compared with experimentally obtained data and were found to be in good accord. The ANN was trained, validated, and tested with the experimental data. The validity of the ANN-based model was ascertained with linear regression analysis and the correlation coefficients were computed. A comparison was made between the numerical simulation-based model and the ANN-based model and it was observed that the artificial neural network-based model predicts the responses faster hence it could be viewed as a potent tool for quicker and more efficient calculation of the weld dimensions and strength in both laboratory and workshop environments. [ABSTRACT FROM AUTHOR]

The 18th International Conference on Aluminium Alloys (ICAA18) was held in Toyama, Japan from September 4 to 8, 2022, and the special issue entitled "Aluminium and Its Alloys for Zero Carbon Society" was published on Materials Transactions in February 2023 (Vol. 64, No. 2). The biennial conference covered a wide range of current trends in aluminium research; e.g. "modeling and simulation", "casting, solidification, recycling and refining", "additive manufacturing", "foams and composite materials", "mechanical properties and advanced processing", "thermomechanical processing, texture and recrystallization", "heat treatment, phase transformation and precipitation", "corrosion and surface treatments", "joining, emerging processes and multi material" and "advanced characterization". This article briefly reviews selected papers from the conference with significant experimental outcome and discussion on aluminium alloys. The author hopes that these papers are useful for all the researchers who develop next-generation technologies and materials concerning aluminium alloys. [ABSTRACT FROM AUTHOR]

In this work, we intended to study the effect of heat treatments (T5 and flash T6) on blistering, mechanical properties and microstructure for different parts produced by vacuum-assisted HPDC. These parts were produced with primary and secondary aluminium alloys (AlSi10MnMg alloy and AlSi10Mg(Fe) alloy, respectively). The parts presented blisters for all combinations of temperature (between 360 °C and 520 °C) and stage times (15 and 30 min) of solution heat treatments. However, when subjected to the T5 heat treatment, blisters were no longer visible. With this heat treatment, there was an increase in yield strength of 64% for both aluminium alloys and an increase in UTS of 31% in AlSi10Mg(Fe) alloy and of 24% in AlSi10MnMg alloy, when compared to the mechanical properties in the as-cast state. However, there was a decrease in ductility. The AlSi10Mg(Fe) alloy presented a lot of contaminations (especially iron), which impaired the mechanical properties compared to the primary aluminium alloy, AlSi10MnMg. [ABSTRACT FROM AUTHOR]

The split-sleeve cold expansion technology is widely used in the aerospace industry, particularly for fastening holes, to enhance the fatigue life of components. However, to ensure proper assembly and improve surface integrity, reaming of the cold-expanded holes is necessary. This study investigates the effects of cold expansion and reaming processes on the fatigue performance of 7050-T7451 aluminum alloy. Fatigue tests, residual stress measurements, and microstructural analyses of the hole edges were conducted on specimens with four different hole diameters after cold expansion and reaming. It was found that the depth of reaming significantly affects fatigue life. During the cold expansion process, the compressive residual stress formed around the hole effectively improves fatigue performance. The experiments demonstrated that reaming by 0.2 mm to 0.4 mm helps eliminate minor defects, thereby improving fatigue life. However, reaming beyond 0.5 mm may lead to stress relief and the removal of dense grains at the hole edges, reducing fatigue life. Therefore, determining the optimal reaming size is crucial for enhancing the reliability of aerospace fasteners. [ABSTRACT FROM AUTHOR]

In the present investigation, a systematic experimental wear study at room temperature on Al2618 and reinforced Al2618 in the solutionized state, and after each pass of equal channel angular pressing (ECAP) was taken up to obtain a fundamental understanding of the wear behaviour and generate reference data on wear properties. The authors prepared a hybrid composite using Al2618 with boron carbide (5 wt.%) and graphite (5 wt.%) by the stir casting process. Solution treated cylindrical specimens of Al2618 and reinforced Al2618 were subjected to four passes of ECAP through a 120° die at room temperature using the processing route (BC). From the results point of view, microhardness measurements were carried out at room temperature on the specimens from the solutionized work piece before and after each pass of ECAP. Scanning electron microscope and X-ray diffraction techniques were used to conduct the microstructural studies. After three passes through both routes, the microstructure showed elongated grains with many dislocations; and after four passes, the microstructure depicted nearly equiaxed grains. Sub micrometre sized grains were produced after three passes of ECAP. Moreover, there was a monotonic increase in the hardness values with an increase in the number of passes. Finally, we reported that there was an improvement in the wear resistance of Al2618 and reinforced Al2618 subjected to ECAP process. This scrutiny may accelerate the applications of aluminium alloys in the industrial sector. [ABSTRACT FROM AUTHOR]

Abstract This study focuses into strategizing the usage of self-reacting bobbin tool friction stir welding (SRBT-FSW) to obtain consistent microstructural homogeneity along the thickness of AA6061 aluminium alloy (AA) thick plates during welding. The SRBT-FSW technology, distinguished by its dual-shoulder design, represents a significant step forward in FSW by eliminating the requirement for a backing anvil and promoting balanced heat distribution. This study seeks to address the issues of maintaining uniform microstructural characteristics throughout the weld zone, which is crucial for the mechanical performance and durability of welded joints in structural applications. The experimental study entails the systematic welding of AA6061 plates of 6 mm thickness using a self-reacting bobbin tool under a fixed processing condition. Electron backscatter diffraction (EBSD) was used to characterize the grain structure and phase distribution over the weld. Mechanical parameters like as tensile strength and hardness were determined to establish correlations between microstructure and mechanical performance. The results demonstrated that SRBT-FSW significantly enhances microstructural homogeneity across the weld zone, leading to improved mechanical properties. In the Bottom Zone (BZ), a refined grain structure with an average grain size (AGS) of 3.53 µm and a random or weak texture was observed, contributing to enhanced hardness and mechanical performance, with an ultimate tensile strength (UTS) of 220 MPa. In contrast, the Top Zone (TZ) exhibited a coarser AGS of 4.33 µm with a pronounced {111} crystallographic texture, resulting in a slightly lower UTS of 205 MPa. The Middle Zone (MZ), influenced by the greater heat input from both the TZ and BZ, showed an intermediate AGS of 3.99 µm, predominantly oriented along the {101} plane, and achieved a UTS of 194 MPa, with a slight reduction in ductility. This study highlights the potential of self-reacting bobbin tool friction stir welding as a reliable method for making high-quality, homogeneous welds in thick aluminium plates and paving way for their wider application in the aerospace, automotive, and shipbuilding industries, where homogeneous microstructural qualities are of significant importance.

The article presents an experimental study on the corrosion resistance of the 3003 Aluminium alloy Friction Stir Welded (FSW) joint in different working environments. Three types of corrosive media at different temperatures were tested to see how they affected the FSW joint mechanical properties. The media were sodium chloride, hydrogen chloride, and ethylene glycol. In parallel with the study of the effect of temperature, static tensile tests were carried out on specimens taken perpendicular to the welding direction. Also, micro-hardness profiles were used to determine the influence of the parameters studied on the various weld zones. Finally, the effect of the most aggressive corrosive medium, temperature, and the inclusion of ethylene glycol on the crack propagation resistance of an FSW joint were studied. Fatigue-propagation tests at constant stress amplitude were carried out to understand what affects the fatigue crack propagation of welded joints after corrosive attack. The results showed that uniform and pitting corrosion were combined to cause FSW joint surface degradation. Corrosion damage does not appear to alter yield strength and ultimate stress values. However, FSW joints show a significant degradation in mechanical properties with increasing temperature and with the aggressiveness of the corrosive medium. The inclusion of ethylene glycol was found to delay the rate of crack propagation during testing, leading to an improvement in the service life of pre-corroded FSW joints.

It is essential to understand the formation and evolution mechanism of intermetallic compounds (IMCs) in friction stir welding (FSW) of dissimilar Al/Mg alloys to mitigate the deleterious effect of hard and brittle IMCs on the performance of dissimilar joints. To this end, a multiphase-field model with input variables of both temperature and strain rate is developed to study the whole IMCs formation and growth process at the Al/Mg bonding interface in weld nugget zone. The effects of diffusion, elastic deformation, and large plastic deformation on the generation and growth of IMCs are considered. The numerical simulation results indicate that due to the influence of high dislocation density, the higher diffusion coefficient of the Mg matrix leads to the nucleation of Al12Mg17 first. When IMCs grow into layers, the higher diffusion coefficient of Al3Mg2 leads to a faster growth rate of Al3Mg2 than that of Al12Mg17. The elastic energy caused by lattice mismatch between IMCs and matrix plays an inhibitory role in the growth of IMCs. Large plastic deformation in FSW causes an increase in both the stored energy which promotes the IMCs growth and the dislocation density which intensifies the diffusion process, causing IMCs to form at the interface in a short time. With the model, the IMCs evolution from generation to growth is quantitatively analyzed. The predicted thickness of IMCs matches well with the experimental measurements.

This study comprehensively investigates the ductility and impact toughness aspects of friction stir additively fabricated (FSAF) components, particularly crucial for applications in aerospace components like stringers and stiffeners. FSAF technology is used to create a fifteen-layered AA6061-T6 build out of 3 mm thick aluminium sheets. A taper threaded tool with a pin length of 4.5 mm (corresponding to a plunge depth of 50% into the lower layer thickness) was used for the experiment. Dynamic recrystallisation resulted in the creation of a stir zone with fine grains, as demonstrated by optical microscopy. Differences in the size of grains, as well as alterations in the distribution, and size of precipitates were observed in the direction of fabrication. The hardness and tensile strength exhibited variations across layers, with the uppermost layer displaying the highest values (82.48 HV and 252.60 MPa, respectively). An impressive milestone was reached with the attainment of 66% ductility, primarily attributed to the process of fragmentation and partial reduction in grain boundary phases. The results of impact toughness have showcased a significant accomplishment as well. Impact tests yielded 112 J and 86 J for the crack-arrester and crack-divider orientations, with enhanced ductility playing a significant role. Delaminations in crack-arrester samples led to higher energy absorption. [ABSTRACT FROM AUTHOR]

The continuous upgrading of the automobile industry has put forward higher requirements for the performance and lightweight effect of aluminum alloys. Heat treatment is an effective way to improve the performance of aluminum alloy, but how to obtain the optimal combination of heat treatment process parameters is an urgent problem. In this paper, the influence of heat treatment process parameters (solution temperature, solution time, aging temperature, aging time) on mechanical properties was systematically studied, and the relationship model between mechanical properties and heat treatment process parameters was established. The micromorphology under different process parameters were analyzed by ESDB and SEM. The results show that when the solution temperature was 530 ℃, the solution time was 1 h, the aging temperature was 170 ℃, and the aging time was 6 h, the mechanical property of 6082 aluminum alloy profiles was the best. The yield strength was 313 MPa, the tensile strength was 350 MPa, and the elongation after break was 13.21%. The relationship model between Y value (yield strength, tensile strength, and elongation after fracture) and key process factors was established, in which the solution temperature had the greatest influence. When the solution temperature was 530 ℃, the grain size was the smallest, and the mechanical properties of the precipitated fine Mg2Si phase and Al(FeMnSi) phase were the best, and the tensile fracture was mainly the dimpled fracture. This paper provides theoretical basis and practical guidance for the optimization of heat treatment process parameters of aluminum alloy profiles. [ABSTRACT FROM AUTHOR]

The joining of AA6082-T6 and polyamide 6 using pinless friction stir spot welding was investigated in this study. The influence of the clamping frame geometry was studied and the welds produced were characterized based on their morphology and mechanical performance. The morphological analysis was evaluated based on the comparison of the different joining areas and on the presence of defects in the resolidified layer of the polymer. In turn, the mechanical performance of the joints was evaluated by tensile-shear testing. Additionally, the influence of plunge depth parameter was studied for the clamping frame geometry providing the best mechanical performance. While the clamping frame geometry had a greater impact on the size of the joining areas, therefore influencing the micro-mechanical interlocking mechanisms, the plunge depth mainly affected the plunging of the aluminium into the polymeric material, therefore affecting the macro-mechanical interlocking mechanism. The strongest joints, which failed for a load of about 2700 N, were produced with the clamping frame geometry that restricted the welding zone the least, and used the highest plunge depth. [ABSTRACT FROM AUTHOR]

The problem of calculation prediction of the overall distortions of a large vessel made of aluminium alloy during friction stir welding (FSW) is considered. A mathematical model was developed using numerical methods of thermoplasticity analysis for determining the stress-strain state during FSW, by means of which it is possible to obtain residual plastic strains (the inherent strain function parameters) for both types of welded vessel joints (longitudinal and circumferential). This makes it possible to predict the overall distortions of a large cylindrical vessel with a great number of welded joints by the approximated method of inherent strains within the limits of the theory of elasticity. The reliability of the mathematical model for determination of the residual stresses and strains at FSW of aluminium alloy is confirmed by the agreement of the calculated distribution of the residual longitudinal stresses with the data of experimental measurements. This can contribute to ensuring the necessary accuracy of predicting the overall distortions of large vessels. The developed mathematical models and calculation algorithms can be effectively used for in-process prediction of the stress-strain state during assembly welding of large cylindrical vessels made of aluminium alloys. [ABSTRACT FROM AUTHOR]

A laser welding with wire filler feeding was developed to replace traditional arc welding process for joining aluminium alloy railcar body components. A three-dimensional (3D) thermo-elastic-plastic finite element (FE) model was applied to compute the plastic strains of weld zone in a downsized aluminium alloy plate with butt-joint, T-joint and fillet-joint configurations, respectively, combined with corresponding experimental validations. The achieved plastic strains at the weld zone were then input as inherent strain loadings into elastic structural FE model of fully sized aluminium alloy railcar body components to predict the welding induced distortion with the experimentally measured out-of-plane distortions. The experimentally validated FE model was then further applied for optimizing the inverse pre-deformation of plates to counteract the welding induced deformation, finally to mitigate the welding distortion issues. [ABSTRACT FROM AUTHOR]

Additive friction stir deposition (AFSD) is an emerging solid-state additive manufacturing process with a high deposition rate. Being a non-fusion additive manufacturing (AM) process, it significantly eliminates problems related to melting such as cracking or high residual stresses. Therefore, it is possible to process reactive materials or high-strength alloys with high susceptibility to cracking. Although the residual stresses are lower in this process than with the other AM processes, depending on the deposition path, geometry, and boundary conditions, residual stresses may lead to undesired deformations and deteriorate the dimensional accuracy. Thermal cycling during layer deposition, which also depends on the geometry of the manufactured component, is expected to affect mechanical properties. To this day, the influence of the deposit geometry on the residual stresses and mechanical properties is not well understood, which presents a barrier for industry uptake of this process for large-scale part manufacturing. In this study, a stepped structure with 4, 7, and 10 passes manufactured via AFSD is used to investigate changes in microstructure, residual stress, and mechanical property as a function of the number of passes. The microstructure and defects are assessed using scanning electron microscopy and electron backscatter diffraction. Hardness maps for each step are created. The residual stress distributions at the centreline of each step are acquired via non-destructive neutron diffraction. The valuable insights presented here are essential for the successful utilisation of AFSD in industrial applications. [ABSTRACT FROM AUTHOR]

The advancement of non-Newtonian nanofluid innovation is a crucial area of research for physicists, mathematicians, manufacturers, and materials scientists. In engineering and industries, the fluid velocity caused by rotating device and nanofluid has a lot of applications such as refrigerators, chips, heat ex-changers, hybrid mechanical motors, food development, and so on. Due to the tremendous usage of the non-Newtonian nanofluid, the originality of the current study is to explore the influence of nanoparticle radii and inter-particle spacing effects on the flow characteristics of Casson methanol-based aluminium alloy (AA 7072) nanofluid through a rotating disc with Joule heating and magnetic dipole. The present problem is modeled in the form of partial differential equations (PDEs), and these PDEs are converted into ordinary differential equations with the help of suitable similarity transformations. The analytical solution to the current modeled problem has been obtained by using the homotopy analysis method (HAM) and numerical solutions are obtained by employing Runge–Kutta–Fehlberg method along with shooting technique. The main purpose of the present research work is to analyze the behavior of the velocity and temperature of the nanofluid for small and large radius of the aluminium alloy (AA 7072) nanoparticles and inter-particle spacing. The radial and tangential velocities are enhanced due to rising ferro-hydrodynamic interaction parameter and the skin friction force for radial and tangential directions are enhanced 10.51% and 2.16% when h = 0.5. Also, the heat transfer rate is reduced 18.71% and 16.70% when h = 0.5% and R p = 1.5. In fact, the present results are compared with the published results and they met good agreement. [ABSTRACT FROM AUTHOR]

Aluminium alloy is increasingly being used in the industries because of its high strength to weight and corrosion resistance ability. However, there is a need to investigate its machinability to ensure that it will meet the quality and functional requirements for its intended applications. Hence, this study employs the computer-aided simulation and experimental approach to investigate the machinability of Al 6065 T6 using response surface methodology (RSM) during milling operation. The RSM was implemented in the Design Expert 2022 environment and the designed experiment produced 20 experimental trials whose responses specifically, maximum contact stress, reaction force, and surface roughness determined via modelling and simulation in the Complete Abaqus Environment (CAE). The validation of the numerical analysis was done by conducting physical experimentations. This established the feasible range of process parameters that can ensure effective machinability of Al 6065 T6 during milling operation. The values of the process parameters that produced the least surface roughness for both the computer-aided simulation and experimental approaches are feed rate (0.07 mm/rev), cutting speed (15 m/min), and tool slip factor (25%). Furthermore, predictive models were developed for estimating the magnitude of maximum contact stress, reaction force, and surface roughness. The statistical analysis of the predictive models indicates that they are suitable for predictive purposes. The outcome of this study adds to the understanding of the machinability of Al 6065 T6. The empirical results can assist machinists to develop products from Al 6065 T6 that will meet the required service requirements. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of the results of the ring rolling process of EN AW-7075 aluminium alloy using numerical modelling. The study of the rheological properties of the AW-7075 aluminium alloy was carried out using the Gleeble 3800 metallurgical process simulator. The modelling of the ring rolling process in the experimental mill was carried out using the Simufact Forming programme based on the finite element method. Based on the analysis of the test results, the speed of the mandrel, the speed of the main roll, the temperature of the metal at the beginning and at the end of the rolling process were determined. The results of research were verified in an experimental mill. [ABSTRACT FROM AUTHOR]

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Surface integrity problems during selective material removal processes are a very common limitation for process productivity and part quality, especially in difficult-to-machine materials like 5083 aluminium alloy (AA), which is known for its remarkable performance in extreme environments. In general, tuning the cutting-part material properties with cutter geometry and cutting parameters can optimize surface texture, increase parts accuracy and resistance in corrosion, and eliminate process noise and energy waste. This work is an experimental study of surface parameter optimization during finish end milling of an AA5083 under a specific range of three cutting parameters with an optimized two-flute carbide cutter by previous work. So, twenty-seven experiments were run having varied the radial depth of cut (RDOC), feed rate (f), and cutting speed (S). Surface roughness parameters (Ra and Rt) were measured in the direction of cutting speed at three different distances by the upper edge. The signal-to-noise (SN) ratios have been calculated, and the process was optimized following the analysis of means. Then, additive models with linear interactions were fitted on SN ratios, and the analysis of variances and residual normality plots were utilized to validate the models' goodness. The SN approach and analysis of means conclude that 0.5 mm RDOC, 6000 rpm speed, and 0.082 mm/tooth feed optimize the process and can effectively predict the Ra and Rt responses. The newly produced machinability data can benefit further applications of AA5083 in industrial applications such as shipbuilding and vehicle bodies. [ABSTRACT FROM AUTHOR]

AlSi10MnMg alloys are investigated with different iron, copper and zinc concentrations. In addition to the varying alloy concentrations, different heat treatments (F, T5 and T7) are carried out and then tested for their thermal conductivity and heat capacity. The test specimens are produced using chill casting. The background to the investigations is the poor recyclability of aluminum alloys with alloy components of iron, copper and zinc, as there is currently no economical method of removing these alloy components. To determine the influence of the alloying elements iron, copper and zinc, measurements of the thermal conductivity and heat capacity are carried out using a hot disk with a transient measurement method. [ABSTRACT FROM AUTHOR]

Aluminium (Al) and magnesium (Mg) alloys are extensively used in the automobile sector because of their high strength‐to‐weight ratio, excellent castability low density and simplicity of recycling. Al‐Mg structures used in the automotive sector can potentially reduce their weight. Although there is a significant opportunity for substantial cost reduction, the use of magnesium in aluminium structures remains restricted. This study aims to weld 3 mm‐thick rolled sheets of AA6061 Al and AZ31B Mg alloy using the cold metal transfer (CMT) arc welding process. Three different filler wires (ER1100, ER4043, and ER5356) were used in the experiment. In this article, the mechanical and microstructure characteristics of Al/Mg dissimilar joints manufactured by CMT are evaluated and discussed in detail. Optical microscope (OM), scanning electron microscopy (SEM), energy dispersive x‐ray spectroscopy (EDX), and x‐ray diffraction (XRD) were used to analyze the CMT‐welded Al/Mg dissimilar joints. Of the three filler wires used, ER4043 (Al‐5%Si) filler wire yielded defect‐free sound joints due to the presence of Si, which improves the flow ability of molten filler during welding. The presence of Mg‐rich intermetallics‐Al12Mg17) and Al‐rich intermetallics‐Al3Mg2 were observed. The fractured area of the CMT‐welded Al/Mg dissimilar joints revealed the presence of the Mg‐rich intermetallics (Al12Mg17), which is responsible for the decrease in tensile strength. The reduction of intermetallics, particularly of Mg‐rich intermetallics (Al12Mg17) is important for improving joint strength. Research Highlights: Cold metal transfer (CMT) arc welding was used to control the Al‐Mg‐rich intermetallics in the Al/Mg dissimilar joints.The microstructure, morphology and phase composition of the welded joints were studied by OM, SEM, TEM, EDS and XRD.The weld metal and AL substrate bonded with a strong interface, while weld metal and Mg substrate were joined at the epitaxial solidification area where the intermetallic compounds of Mg2Al3, Mg17Al12 and Mg2Si are generated.The weld metal on the Mg side experienced brittle fracture, with a continuous distribution of Mg2Al3, Mg17Al12 and Mg2Si. [ABSTRACT FROM AUTHOR]

In the present study, three reinforcements viz. graphite, SiC and Al2O3 were added in LM6 matrix to evaluate their strengthening efficiency. Stir casting technique was utilised for fabrication of composites, where the amount of reinforcements varied from 1.0 wt.% to 3.0 wt.%. Hardness and tensile strength was performed to evaluate the mechanical properties and optical microscopy was utilised to analyse the microstructure of the prepared composites. It was observed that the tensile strength and hardness increased linearly, irrespective of the reinforcement type and content. However, graphite reinforced composites exhibited best mechanical properties followed by SiC and Al2O3 reinforced composites. From the optical microscopy images, it was clearly observed that as the concentration of reinforcement increased, the tendency to form agglomerates also increased eventually resulting in porosities. However, composites containing large amount of reinforcements still displayed highest values of tensile strength and hardness. This might be attributed to the fact that the detrimental effect of porosities was negligible as compared to the strengthening effect exerted by the reinforcements. [ABSTRACT FROM AUTHOR]

The results of consumable electrode pulsed-arc welding of 1561 aluminium alloy of 6 mm thickness (P-MIG) with and without addition of focused radiation of the Nd:YAG laser were analyzed. During laser-P-MIG welding, the influence of the arc energy source improves absorption of laser radiation and promotes high-quality formation of the weld reinforcement, and the influence of the laser source leads to an increase in the depth of penetration due to the formation of a vapour-gas channel (keyhole) and to a decrease in the current density of the anode region of the arc on the electrode wire, which reduces emissions of welding aerosols. Factors influencing the effectiveness of laser radiation during laser-P-MIG welding were determined. It is shown that an increase in laser power leads to an increase in arc voltage with a simultaneous decrease in welding current. Formation of high-quality welds by P-MIG welding of 1561 alloy requires an energy input of 4.5-5.0 kJ/cm. Here, a regular structure of the weld metal with the dendritic parameter of 13-15 µm and joint strength of 90-92 % of the strength of the base metal is formed. Introduction of focused radiation of a 3.0 kW Nd:YAG laser into the welding process allows reducing the energy input by approximately half, due to which the dendritic parameter decreases to 10 µm, and the strength of the joints increases to 93-96 % of base metal strength. [ABSTRACT FROM AUTHOR]

Wire Arc Additive Manufacturing (WAAM) of thin walls is an adequate technology for producing functional components made with aluminium alloys. The AlMg5 family is one of the most applicable alloys for WAAM. However, WAAM differs from traditional fabrication routes by imposing multiple thermal cycles on the material, leading the alloy to undergo cyclic thermal treatments. Depending on the heat source used, thermal fluctuation can also impact the microstructure of the builds and, consequently, the mechanical properties. No known publications discuss the effects of these two WAAM characteristics on the built microstructure. To study the influence of multiple thermal cycles and heat source-related thermal fluctuations, a thin wall was built using CMT-WAAM on a laboratory scale. Cross-sections of the wall were metallographically analysed, at the centre of a layer that was re-treated, and a region at the transition between two layers. The focus was the solidification modes and solubilisation and precipitations of secondary phases. Samples from the wall were post-heat treated in-furnace with different soaking temperatures and cooling, to support the results. Using numerical simulations, the progressive thermal cycles acting on the HAZ of one layer were simplified by a temperature sequence with a range of peak temperatures. The results showed that different zones are formed along the layers, either as a result of the imposed thermal cycling or the solidification mode resulting from CMT-WAAM deposition. In the zones, a band composed of coarse dendrites and an interdendritic phase and another band formed by alternating sizes of cells coexisted with the fusion and heat-affected zones. The numerical simulation revealed that the thermal cycling did not significantly promote the precipitation of second-phase particles. [ABSTRACT FROM AUTHOR]

This paper presents the results of mechanical tests on AlSi10Mg alloy matrix composites reinforced with natural and synthetic graphite particles. The natural graphite used as reinforcement in the composite was flake graphite of very high purity, chemically refined, while the synthetic graphite came from recycled graphite electrodes used in electric arc furnaces. Composite slurries containing 5, 10 and 15 % graphite particles were die-cast on a cold chamber die casting machine. Samples of pure AlSi10Mg alloy were also cast.

This study investigates the application of Friction Stir Welding (FSW) for fabricating stiffened structures in AA2219-T31 using a T-lap configuration. These structures are vital in various applications where weight is a crucial factor, including aircraft fuselages, railway cars and automotive parts. This study assesses the formation dynamics of lack of bonding in single-pass welds, including the examination of microstructure, hardness, mechanical properties, and fracture locations. A second welding pass was employed over the initial weld to eliminate the lack of bonding. The implementation of a second welding pass significantly improves joint efficiency, achieving up to 90 % of the ultimate tensile strength in the skin direction and 95 % in the stiffener direction, establishing a new benchmark for AA2219-T31 T-joints. Additionally, no significant differences in grain size were found between single- and double-pass welds, highlighting the lack of bonding as key factor affecting the strength of the joints. The proposed method offers valuable insights for future industrial applications to avoid defects such as lack of bonding.