Commercial Aluminum Research Articles

Exploiting Friedel pairs to interpret scanning 3DXRD data from complex geological materials

The present study introduces a processing strategy for synchrotron scanning 3D X-ray diffraction (s3DXRD) data, aimed at addressing the challenges posed by large, highly deformed, polyphase materials such as crystalline rocks. Leveraging symmetric Bragg reflections known as Friedel pairs, our method enables diffraction events to be precisely located within the sample volume. This method allows for fitting the phase, crystal structure and unit-cell parameters at the intra-grain scale on a voxel grid. The processing workflow incorporates several new modules, designed to (i) efficiently match Friedel pairs in large s3DXRD datasets containing up to 108 diffraction peaks; (ii) assign phases to each pixel or voxel, resolving potential ambiguities arising from overlap in scattering angles between different crystallographic phases; and (iii) fit the crystal orientation and unit cell locally on a point-by-point basis. We demonstrate the effectiveness of our technique on fractured granite samples, highlighting the ability of the method to characterize complex geological materials and show their internal structure and mineral composition. Additionally, we include the characterization of a metal gasket made of a commercial aluminium alloy, which surrounded the granite sample during experiments. The results show the effectiveness of the technique in recovering information about the internal texture and residual strain of materials that have undergone high levels of plastic deformation.

Influence of HEA reinforcement on pulse electric current sintered Aluminium Composites: Microstructure, Density, and nanomechanical properties

This study investigates how different compositions of high-entropy alloys (HEAs), known for their strength and thermal stability, affect the microstructure, density, and nanomechanical properties of aluminium matrix composites produced by pulse electric current sintering (PECS). Commercial aluminium was reinforced with 5%, 7%, and 10% HEA and sintered using PECS. Microstructural analysis showed improved particle bonding and dispersion, resulting in enhanced mechanical properties. Although relative density slightly decreased with higher HEA content, there was a significant enhancement in nanohardness and elastic modulus. The composites exhibited improved resistance to plastic deformation and increased stiffness, thus, highlighting the effectiveness of HEA reinforcement in optimizing aluminium composites for high-strength, lightweight, and advanced engineering applications. These findings offer valuable insights for developing next-generation materials suited to demanding engineering environments.

Attention Pyramid Dilated Region-based Model for Metallurgical Defect Detection

Abstract Defect recognition is the key to realizing automatic visual inspection and quality control in intelligent manufacturing. Deep learning (DL) has been widely applied to locate damaged areas in images, characterize impurities of materials and further analyze the quality of products. However, automatic defect detection by DL in practical industrial applications is still a challenge due to the lack of sufficient datasets and appropriate recognition methods. Here, a novel Attention Pyramid Dilated Region-based Convolutional Neural Network (ADRCNN) is proposed to realize the multi-scale defect recognition and pixel-level instance segmentation of metallographic images. We also collected a dataset containing 900 images of commercial A356 aluminum alloy with different casting defects. The ADRCNN model is evaluated on our dataset with an average detection accuracy of 87.2% and 93.3% on validation and test sets respectively. To address the overfitting problem, a pretraining fine-tuning strategy is implemented by using the pretraining weights from large-scale datasets and temporarily freezing the weights of the backbone network during the training process. The experimental results show that the proposed model can achieve satisfactory defect segmentation in metallographic images, promoting the development of intelligent manufacturing in alloy industries.

Characterization of L12-Al3Ce phase and its purification mechanism in the Al-Ce-TiCN alloy

Rare earth element Ce has a positive purifying effect on Fe and Si impurities in pure aluminum. In this study, we unveiled the mechanism of Ce purification of Fe and Si impurities in commercial pure aluminum at the atomic scale via utilizing the properties of TiCN nanoparticles, which exhibit distribution along grain boundaries and impede solute atom diffusion at specific cooling rates. The transition phase L12-Al3Ce was characterized in aluminum, which is considered to be an important transition phase to purified products. Furthermore, High Angle Dark Field Scanning Transmission Electron Microscopy (HADDF-STEM) and 3D Atom Probe Tomography (3D-APT) results showed that Ce could respectively enrich the Fe and Si impurities, resulting in the formation of Al-Ce-Fe and Al-Ce-Si clusters. Density functional theory (DFT) results indicated that Fe and Si atoms can incorporate into L12-Al3Ce crystal, forming more stable structures and therefore giving rise to the formation of Al-Ce-Si and Al-Ce-Fe nanoclusters. This study provides atomic-scale insights into the mechanism of Ce purifying Fe and Si impurities in aluminum.

SEM-DIC characterization of the damage mechanism of an AlSi10Fe0.7 casting alloy on the microstructure scale

Various brittle phases are present in commercial cast aluminum alloys, which strongly influence their mechanical behavior. Among these, silicon precipitates are nearly omnipresent, as Si is a common alloying element. In secondary alloys, usually Fe-containing phases cannot be avoided, and they tend to degrade the mechanical properties. The interaction between the silicon phase and the failure-critical intermetallic phase in the Al-Si-Fe phase system (β-Al5FeSi) is studied in this paper in high resolution. A model alloy AlSi10Fe0.7 was defined, which is composed of a large grain Al-matrix, Si-precipitates and the plate-like β-Al5FeSi phase. The goal of the study was to identify “hot spots” in the microstructure from which cracks may initiate under mechanical loading. The main tool was a deformation analysis via digital image correlation in the SEM (SEM-DIC). This allows the identification and tracking of developing strain localizations at different potential crack initiation sites with a high resolution as well as capturing an overview over the whole specimen. An adapted frame averaging script minimized measurement errors induced by drift. The SEM-DIC results show that the deformation field is governed by the elastic incompatibility of the microstructural constituents. Crack initiation occurs because of the detachment of the Si + β-Al5FeSi phase boundary. Cracks then cross the phase boundary and propagate along twin boundaries in the β-Al5FeSi phase. Final failure is caused by linking fractured brittle plate-like particles.

Effect of heat treatment before fast multiple rotation rolling on friction surfaced Al–Si–Cu alloy

In this study the effect of combination of heat treatment of consumable rod and solid solution heat treatment before fast multiple rotation rolling (FMRR) processing on microstructure, mechanical property and wear resistance of Al–Si–Cu alloy friction surfaced on commercial pure aluminum alloy were investigated. Results show that after the FMRR process, there is a significant reduction (99% reduction) in the friction surfaced coating surface roughness. The surface roughness after FMRR processing in the coatings created by homogenized and solid solution treated consumable rod is 0.74 ± 0.12, and 0.56 ± 0.08 μm, respectively. In the coating created by homogenized rod the minimum grain size (1.7 ± 0.2 μm) formed in the FMRR processed layer. Using homogenized consumable rod and FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, the maximum hardness (9.8 ± 0.3 GPa) and minimum wear rate (4.6 ± 0.1 μg/m) created at processed layer. FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, result in 27 and 24 % increasing in hardness at friction surfaced coating created by homogenized and solid solution treated consumable rods, respectively.

Nanofluidic ion-exchange membranes: Can their conductance compete with polymeric ion-exchange membranes?

Nanofluidic membranes (NFMs) are gaining prominence as alternative ion-exchange membranes, because of their distinct selectivity mechanism, which does not rely on functional groups on a polymeric backbone but rather on charged nanopores that allow straight ion-conductive pathways for efficient ion transport. We measured the conductivity of commercial anodized aluminum oxide membranes with different pore sizes under different current densities and electrolyte concentrations. We also simulated a nanopore channel with charged walls between two electrolyte reservoirs. Our findings indicate that electrolyte concentration is the main parameter that determines NFM conductivity, with a linear dependence at least up to 1 M. Our study shows that the optimal pore length is between 0.5 and 5 μm considering the trade-off between selectivity and conductance. On the other hand, the conductance is not sensitive to the pore diameter. Conical nanopores are a way to increase conductance, but according to our results, this increase comes at the expense of selectivity. Our findings suggest that NFMs can outperform polymeric ion-exchange membranes in certain electrochemical applications, such as reverse electrodialysis, but not in applications that use low electrolyte concentrations on both sides of the membrane.

Implications of Ultrasonication-assisted Extraction with Response Surface Methodology on Phytochemical Compositions and Antioxidant Activity of Polysaccharide Extract from Phellinus rimosus (Berk.) Pilát Cultivated Mycelia in Northeastern Thailand

Background: Polysaccharides from the medicinal mushroom Phellinus rimosus (Berk.) Pilát (PR) are the major functional bioactive ingredients. However, there has been a marked natural decrease in the number of PR fruit bodies, leading to their increased cost. Moreover, the natural growth and development of mature PR fruit bodies takes several decades. Objective: The objective of this study was to produce a polysaccharide extract from cultured PR mycelia (PEPRM) by using ultrasonic-assisted extraction with response surface methodology (RSM), and determine its physicochemical composition and antioxidant potential. Methods: Polysaccharide and monosaccharide composition analyses were carried out by Fouriertransform infrared spectroscopy (FT-IR) and High-performance liquid chromatography (HPLC). Total contents of polysaccharides, beta-glucans, phenolic compounds, and flavonoids were investigated utilizing the phenol-sulfuric acid method, enzymatic-based commercial test kit, Folin-Ciocalteu method, and aluminium chloride colorimetric method, respectively. Antioxidant activity was determined by using 2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH) radical scavenging assay and 2,2- azino-bis (3-ethylbenzothiazol-6-sulfonic acid) (ABTS) radical cation decolorization assay. Results: Optimal conditions for the production of PEPRM included a ratio of 51.29 mL water to 1 g PR mycelia and an extraction time of 46.23 minutes, resulting in a total polysaccharide content of 577.5 mg/g of PEPRM. FT-IR spectra of PEPRM showed two broad bands at 3272.08 cm-1 and 2924.8 cm-1 in the carbohydrate region and the peaks at 1078.44, 1019.05, and 853.0 cm-1 indicated the presence of the pyranose ring skeleton, glycosidic linkage, and glucans. PEPRM had molar ratios of glucose: mannose: rhamnose: fucose, i.e., 21.86: 1.00: 2.08: 3.40, respectively. PEPRM had total contents of beta-glucans, phenolic compounds, and flavonoids as percentages of dry weight, i.e., 21.22, 2.51, and 5.71, respectively. PEPRM showed better inhibitory activity against ABTS radicals than DPPH radicals. result: Optimal conditions for the production of PEPRM were a ratio of 51.29 ml water to 1 g PR mycelia and extraction time of 46.23 min, yielding a total polysaccharide content of 577.5 mg/g of PEPRM. FT-IR spectra of PEPRM showed two broad bands at 3272.08 cm-1 and 2924.8 cm-1 in the carbohydrate region and the peaks at 1078.44, 1019.05, and 853.0 cm-1 indicated the presence of the pyranose ring skeleton, glycosidic linkage, and glucans. PEPRM had molar ratios of glucose: mannose: rhamnose: fucose, i.e., 21.86: 1.00: 2.08: 3.40, respectively. PEPRM had total contents of beta-glucan, phenolic compounds, and flavonoids as percentages of dry weight, i.e., 21.22, 2.51, and 5.71, respectively. PEPRM showed better inhibitory activity against ABTS radicals than DPPH radicals. Conclusion: This is the first finding to reveal that ultrasonic-assisted extraction with RSM was an environmentally friendly alternative to produce antioxidant polysaccharides from cultured PR mycelia. conclusion: This is the first finding to reveal that ultrasonic-assisted extraction with RSM was an environmentally friendly alternative to produce antioxidant polysaccharides from cultured PR mycelia.

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

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

Water-Soluble and Freezable Aluminum Salt Vaccine Adjuvant.

Particulate aluminum salts have long occupied a central place worldwide as inexpensive immunostimulatory adjuvants that enable induction of protective immunity for vaccines. Despite their huge benefits and safety, the particulate structures of aluminum salts require transportation and storage at temperatures between 2 °C and 8 °C, and they all have exquisite sensitivity to damage caused by freezing. Here, we propose to solve the critical freezing vulnerability of particulate aluminum salt adjuvants by introducing soluble aluminum salts as adjuvants. The solubility properties of fresh and frozen aluminum chloride and aluminum triacetate, each buffered optimally with sodium acetate, were demonstrated with visual observations and with UV-vis scattering analyses. Two proteins, A244 gp120 and CRM197, adjuvanted either with soluble aluminum chloride or soluble aluminum triacetate, each buffered by sodium acetate at pH 6.5-7.4, elicited murine immune responses that were equivalent to those obtained with Alhydrogel®, a commercial particulate aluminum hydroxide adjuvant. The discovery of the adjuvanticity of soluble aluminum salts might require the creation of a new adjuvant mechanism for aluminum salts in general. However, soluble aluminum salts might provide a practical substitute for particulate aluminum salts as vaccine adjuvants, thereby avoiding the risk of inactivation of vaccines due to accidental freezing of aluminum salt particles.

Experimental investigation on extrinsic size effect in micro-orthogonal cutting of commercial aluminium alloy

The achievable precision in micro-machining is constrained by a phenomenon known as the size effect. The edge radius of the tool significantly influences the size effect leading to non-proportional scaling of process performance. The process becomes unscalable below a certain ratio of uncut chip thickness to edge radius termed as critical relative tool sharpness (RTS). Despite extensive studies on the size effect associated with non-linear process performance, very limited studies have focused on the critical RTS range. In the present study, orthogonal cutting experiments were conducted on a commercial aluminium alloy (Al6060) with different cutting-edge radiuses in the RTS range of 0.5 to 0.01. Extensive analysis of the morphology of the chips and tool-work material adherence has been carried out and correlated with the observed size effect on surface integrity. One of the key findings in this study was the size effect in the chips with respect to the chip curl radius and pitch. Between RTS 0.5 and 0.09, an increase in chip curl and pitch is observed, followed by a sharp fall up to RTS 0.07. In addition, another notable phenomenon was the formation of dual-layered chips with deformed layer on the rake side and lamellae like features on the free side. Furthermore, size effect was observed in surface roughness, surface hardness and flank adherence. In summary, the present investigation offers a comprehensive understanding of the size effect within the critical RTS range elucidating its multifaceted impact on micro-cutting.

Microstructure, tensile strength, and hardness of AA5024 modified with ZrH4 additions produced by laser powder bed fusion

This work investigates the effect of ZrH4 additions on a commercial AA5024 aluminum alloy produced via Laser Powder Bed Fusion (L-PBF) where pre-mixed powders of AA5024 and ZrH4 were used. The microstructure was characterized using light and scanning electron microscopy assisted by energy-dispersive X-ray spectroscopy, and electron backscattered diffraction. The mechanical properties were evaluated by hardness and tensile measurements. The ZrH4 additions modify the microstructure. Regions without particles originate the large and elongated grains, while regions with undissolved ZrH4 or formed particles during solidification originate a fine equiaxed microstructure. The fine-grained region is typically located at the boundary of the melt pools, while the coarse-grained region is formed within the melt pools. There is substantial grain refinement with additions higher than 2.0 wt% ZrH4, nearly eliminating the coarse-grained region. The grain size does not differ in the fine-grained region for the different ZrH4, cross-sections (perpendicular or along the printing direction), or printing parameters. The 〈110〉 crystallographic fiber texture is identified, and a few particular texture components are more pronounced, such as the Cube {001} 〈100〉, the rotated Cube {001} 〈110〉, the Goss {011} 〈001〉, and Z {111} < 110>. Low texture index values are obtained in the fine-grained region, indicating the highly isotropic microstructure. The hardness and tensile strength increase with the increase in ZrH4 content for the as-built condition. A saturation in tensile strength is reached after 1.0 wt% ZrH4 additions.

Observation of the formation of CuAl2O4 by the direct consumption of Al2O3 in an NAB alloy at elevated temperature

The oxidation behaviors of a commercial C95500 nickel aluminum bronze (NAB) alloy at elevated temperatures were investigated. The oxide scale exhibited a triplex structure with an outmost CuAl2O4 layer, an intermediate spinel-type Al2O3 layer, and a deepest nano Al2O3 film. The observation of CuAl2O4 and Al2O3 in the same grain with the same crystallographic orientation indicated that the outmost CuAl2O4 was formed by directly consuming the spinel-type Al2O3. Such a transformation process can avoid the formation of defects in the oxide scale caused by the transformation between different Al2O3 variants, attributing to the origin of the excellent oxidation resistance.

Optimization and Simulation Parameters of the Resistance Spot Welding for Commercial Aluminium (AA1050) at Low Power Welding Machine

This study aims to find the best conditions of resistance spot welding in commercial Aluminium AA1050 to obtain the maximum tensile shear strength of the joint using a low-power supply welding machine. The chosen parameters for this study were welding current, welding time, and electrode force using a 90 kVA welding machine. The investigation used the DoE method with Taguchi’s technique to reduce the number of experiments where two sheet thicknesses (1 mm and 2 mm) were used in this work. The software program Minitab 18 analyzed the results using the main effects plots and the interaction plots to identify the most significant parameters and their effect on the joint strength. The best conditions for maximum tensile shear force were 14.85 kA welding current and 0.79 kN electrode force for both thicknesses and two cycles and 12 cycles welding time for 1 mm and 2 mm sheet thickness, respectively. The maximum tensile strength obtained was 250 N and 225 N for 1mm and 2mm sheet thickness, respectively. A mathematical equation was developed to predict the shear force with 19.9 % and 17.9 % error for 1 mm and 2 mm thicknesses, respectively. The best conditions were applied in ANSYS 2022R1 multi-physics to obtain the temperature distribution with time history, where the result shows the nugget size according to the molten temperature. The percentage of discrepancy between actual and numerical nugget size was 8 %.

Copper, potassium promoted iron on metallosilicate and aluminum oxide supports synthesized via a non-hydrolytic sol-gel for Fischer-Tropsch

We developed a promoted iron based catalyst that converts 20% more CO to diesel than the unpromoted counterparts. The synthesis involves a non-hydrolytic sol-gel method (NHSG) and 0.04 g g−1 copper and 0.02 g g−1 potassium as promoters. The iron catalyst supports included cerium and zirconium metallosilicates and Catalox and Dispal commercial aluminum oxides from Sasol. At 325 ∘C and 20 bar, CO conversion over the Fe/Ce/SiO2-K,Cu, exceeded 85% while at the same conditions it was only 68% over the unpromoted catalyst. Fe/Zr/SiO2-K,Cu converted less CO than the cerium-silicate (75%) but the unpromoted zirconium-silicate only converted 43% of the CO. The conversion and selectivity of the Catalox was about the same as the cerium-silicate, while the Dispal performance was equivalent to the zirconium-silicate. This study also highlights the importance of support and promoters in FTS, demonstrates the potential of the NHSG method to synthesize promoted iron catalysts with various supports and lays the foundation for developing efficient and stable catalysts for converting syngas to hydrocarbons.

Enhancement of Creep Lifetime of Aluminum through Severe Plastic Deformation

This work investigates the creep behavior of severely deformed commercial aluminum. The commercial aluminum was processed by helical rolling (HR) and equal-channel angular pressing (ECAP) at room temperature. During these processes, the equivalent strain up to about 4 was imposed into the as-received material. The creep testing at 200 °C revealed that HR and ECAP significantly increased the time to fracture compared to the as-received material. The stress dependences showed that the value of stress exponent n decreased with the value of the imposed strain. The stress-change tests showed that as-received and severely deformed states exhibited different recovery rates after unloading. The microstructure analysis showed that creep behavior was influenced by the microstructure formed during severe plastic deformation. The relationships between creep behavior and microstructure in the investigated states are discussed.

Green industry work: production of FeCl3 from iron and steel industry waste (mill scale) and its use in wastewater treatment

Mill scale (MS) is considered to be a significant metallurgical waste, but there is no economical method yet to utilize its metal content. In this study, which covers various processes in several stages, the solution of iron in MS, which is the Iron and Steel Industry (I&SI) waste, as FeCl3 (MS-FeCl3) in the thermoreactor in the presence of HCl, was investigated. In the next step, the conditions for using this solution as a coagulant in the treatment of I&SI wastewater were investigated using the jar test. The results of the treated water sample were compared by chemical oxygen demand (COD), total suspended solids (TSS), color, and turbidity analyses using commercial aluminum sulfate (Al2(SO4)3) and FeCl3 (C-FeCl3). Additionally, heavy metal analyses were conducted, and the treatment performance of three coagulants was presented. Accordingly, while 2.0 mg/L anionic polyelectrolyte was consumed at a dosage of 4.05 mg/L Al2(SO4)3 at pH 7.0, 0.25 mg/L anionic polyelectrolyte was consumed at a dosage of 1.29 mg/L at pH 5.0 in the C-FeCl3 and MS-FeCl3 studies. Also, Fe, Cr, Mn, Ni, Zn, Cd, Hg, and Pb removal efficiencies were over 93.56% for all three coagulant usage cases. The results showed that the wastewater treatment performance of MS-FeCl3 by the recycling of MS, which is an I&SI waste, was at the same level as C-FeCl3. Thus, thanks to recycling, waste scale can be used as an alternative to commercial products for green production.Graphical abstract

Nanocontrolled thinning of the barrier layer thickness of porous anodic films using galvanodynamic polarization of aluminum alloys

Thinning the barrier layer thickness of anodic films prepared on refined aluminum substrates (4 N or 5 N) was usually performed to elaborate -after the usual two-step anodizing method- anodic aluminum oxide (AAO) templates with pores opened at both sides, allowing the subsequent nanodevices synthesis. By contrast, there is a lack of studies concerning similar barrier layer thinning for anodic films grown -by a single-step anodizing - on commercial low alloyed aluminum substrates (1XXX series) or other more complex aluminum alloys (AA 2XXX-8XXX). Yet such a need is now emerging, particularly for future applications requiring transverse electrical conductivity of usual anodic films toward the aluminum alloy substrate.This work aims to study and to master a simple and cheap method for thinning the barrier layer thickness of such anodic films on commercial aluminum alloys. Here, the thinning is studied using a current density decrease (at a constant rate) after the anodic film growth in phosphoric acid-based electrolyte, using the conjunction of in-situ accurate electrochemical follow-up and ex-situ FE-SEM morphological observations. Variation of current density scan rate highlights that fast processes lead to no barrier layer thinning, and slow ones to the detachment of the whole oxide film. However, by choosing the right scan rate range, it is possible to successfully obtain, in a straightforward manner, anodic films still supported on aluminum alloy substrates, but with barrier layer thickness tuned at the nanoscale.

Atmospheric corrosion acceleration effect on commercial aluminum alloys in current-carrying condition

PurposeThe purpose of this paper is to study the effect of current-carrying condition on the electrochemical process and atmospheric corrosion behavior of the commercial aluminum alloys.Design/methodology/approachPotentiodynamic polarization tests were performed to study the electrochemical process of the aluminum alloys. Salt spray tests and weight loss tests were carried out to study the atmospheric corrosion behavior. The corrosion morphology of the alloys was observed, and the products were analyzed.FindingsThe corrosion process of four aluminum alloys was accelerated in the current-carrying condition. Moreover, the acceleration effect on A2024 and A7075 was much stronger than that on A1050 and A5052. The main factors would be the differences in microstructure and corrosion resistance between these alloys. As the carried current increased, the corrosion rate and corrosion current density of the aluminum alloys gradually increased, with the protection of the corrosion product film decreasing linearly.Originality/valueThis is a recent study on the corrosion behavior of conductors under current-carrying condition, which truly understands the corrosion status of power grid materials. Relevant results provide support for the corrosion protection and safe service of aluminum alloy in power systems.

Uticaj hladne plastične deformacije nakon starenja na mehaničke osobine i mikrostrukturu aluminijumske legure EN AW-7075

This paper presents research on the changes in the mechanical and structural properties of the commercial aluminum alloy EN-AW 7075 during thermomechanical processing. The processing involved artificial aging of the alloy at a temperature of 150°C for 30 minutes, followed by cold rolling after aging. Changes in hardness and impact toughness during the experiment were monitored. Hardness was measured using the Leeb method, while impact toughness was measured using the Charpy method. In the annealed state, the lowest hardness values were recorded, while the highest-impact toughness value was achieved in the as-quenched state. By applying cold plastic deformation after artificial aging, the hardness of the alloy significantly increased, while the impact toughness continuously decreased. After deformation of 20%, cracks appearance prevented further deformation. Optical microscopy was used to follow microstructural changes during the applied processing regime. Precipitates of various sizes and morphologies were observed in the structure. The annealed state results in poorly defined grain boundaries and formation of large precipitates relatively evenly distributed throughout the matrix. Cold plastic deformation after aging has resulted in elongated grain structure aligned with the rolling direction, along with crushing of secondary phase particles.