An age-hardenable Al–4wt% Cu alloy is severely deformed using high-pressure torsion (HPT) to refine the microstructure to an average gain size of ~210nm. High saturation hardness of 205Hv and high ...tensile strength of 820MPa are achieved after the HPT processing. It is shown that the strength of the HPT-processed alloy is further improved by natural aging at room temperature or by artificial aging at 353K. A peak hardness followed by softening appears within a few days after natural aging and within a few minutes after aging at 353K, suggesting the low thermal stability of the alloy. Quantitative evaluation of different strengthening mechanisms shows that the grain boundary hardening through the Hall–Petch relationship and the precipitation hardening through the Orowan relationship are dominant strengthening mechanisms.
•The corrosion on new aerospace aluminum alloy is studied.•Al7Cu2Fe precipitate was detected in the 7475-T7351 and 7081 T73511 alloy by scanning electron microscopy.•Al7Cu2Fe particles have different ...morphologies depending on the forming process.•Corrosion pitting occurs around Al7Cu2Fe precipitates in 7475-T7351 and 7081-T73511 alloys.
The development of aluminum alloys of the Al–Zn–Mg–Cu system is the primary factor that enabled the evolution of aircraft. However, it has been shown that these alloys tend to undergo pitting corrosion due to the presence of elements such as iron, copper and silicon. Thus, the purpose of this study is to evaluate the behavior of the Al7Cu2Fe precipitate in 7475-T7351 and 7081-T73511 alloys based on microstructural characterization and polarization tests. The corrosion and pitting potentials were found to be very similar, and matrix dissolution occurred around the Al7Cu2Fe precipitate in both alloys, revealing the anodic behavior of the matrix.
Laser shock peening (LSP) of 6061-T6 aluminum alloy was performed and parametric effects post LSP on mechanical aspects and microstructural evolution are meticulously studied using various means of ...characterization techniques such as residual stress analysis, surface roughness, Vickers microhardness, tensile testing, X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and electron back scattered diffraction (EBSD). Work hardened layer of ∼1500 μm depth is obtained with significant improvement in cross-sectional microhardness up to 33.04 %. Beneficial compressive residual stress of maximum magnitude up to -273 MPa was induced in laser peened specimens concentrating its overall effect around the depth of 100 μm along the effective depth region. Second phase Mg5Si6 (βʺ) precipitates were observed post LSP while analyzing XRD profiles along with the peak broadening and peak shifting towards higher 2θ angle justifying the results obtained in residual stress profile. Mg5Si6 (βʺ) precipitates are attributed as contributing precipitates in improving the mechanical properties of LSPed specimens along with the dense dislocation density caused by severe plastic deformation during LSP. High angle grain boundaries (HAGBs) fraction was increased in LSPed specimens and its effect is noticed in microhardness profile. The collective contribution of strain hardening, second phase precipitates, peak broadening, dislocation density and increased fraction of HAGBs is observed in mechanical and microstructural aspects of LSPed specimens. The results are discussed in detailed and are strongly correlated with each other.
•T74 and RRA almost can’t improve the SCC resistance of AA7097 compared with T6.•SQA can greatly improve the SCC resistance of AA7097 compared with T6.•Copper in GBPs in T74 is almost the same as ...T6.•Higher copper and larger size of GBPs in SQA than T74 and T6.
The influence of heat treatment on stress corrosion cracking resistance of a low-Cu containing Al-Zn-Mg-Cu aluminum alloy has been investigated. The results show that the stress corrosion cracking resistance is significantly improved by step-quench and aging heat treatment whereas retrogression and re-aging heat treatment and two-stage over aging heat treatment could hardly enhance the stress corrosion cracking resistance compared with peak aging. The improved stress corrosion cracking resistance of the low-Cu containing Al-Zn-Mg-Cu aluminum alloy subjected to step-quench and aging heat treatment is mainly attributed to grain boundary precipitates with high Cu content, large size and discontinuous distribution.
The scope of this Special Issue focuses on the formation of the structure of light alloys, (particularly on an aluminum base) during solidification, deformation, and heat treatment and its ...relationship with mechanical and technological properties. The design of light alloys (including composite materials) based on experimental and theoretical studies is also considered. The Special Issue contains 11 papers, including 10 research papers and 1 review (on the asymmetric (hot, warm, cold, and cryo) rolling of light alloys).
•New 7075-T6 aluminum reinforced with SiC particles composites were tested under tensile conditions.•SiC particles improve the strength and ultimate tensile strength.•Microstructure analysis results ...about (Al-Cu-Fe), (Al-Fe), (Al-Fe-Si) and ƞ (MgZn2) and S (Al2CuMg) phases.•The specimen with 1 wt% of nanoparticles improved the ultimate tensile strength about 21.33%.
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In this study, an experimental analysis for the mechanical properties of 7075-T6 aluminum reinforced with SiC particles with three different sizes of nanometer, submicron and micron scales is performed. The composites are made by vortex casting method. Standard tensile test specimens are fabricated by CNC machining. Finally, according to the standard, the tensile experimental test is performed on the selected samples. To perform the tensile test, first the specimens are fixed in the jaws of the device and then at a velocity of 0.2 mm/min is applied, until the specimens are failed. The base alloy in micro scale is examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) images. Field emission scanning electron microscopy (FESEM) images are also used to show the distribution of nanoparticles in the base and it is found that the size of nanoparticles in the base is less than 100 nanometers. SEM images and X-ray diffraction spectroscopy (EDS) analysis results show the presence of phases (Al-Cu-Fe), (Al-Fe), (Al-Fe-Si) and phases ƞ (MgZn2), S (Al2CuMg) in 7075-T6 aluminum alloy. In general, by adding reinforcing particles to aluminum, the ultimate tensile strength increases, except for micron particles with a 5 wt%. This is while the percentage of elongation of composites compared to 7075 aluminum is decreased. Among the nanoparticle-sized specimens, the specimen with 1 wt% of reinforcing particles improved the ultimate tensile strength, which is equivalent to 21.33%. Submicron and micron particles-reinforced specimens, the 2 wt% specimen, improved the ultimate tensile strength about 16.10% and 11.65%, respectively. Hence, it can be concluded that the particles in nanoscale has more effect on the tensile strength of the composite structure.
In this study, we prepared micro-nano hierarchical structure superhydrophobic 7055 aluminum alloy surface via electrolytic polishing and 0.7-g/L MgCl2 aqueous solution etching followed by ...Perfluorooctyltriethoxysilane modification. The C–F groups with a low surface energy on the surface have great significance to the eventual formation of the superhydrophobic surface, and the dense micron petal-shaped structures can avoid the generation of chloride ion channels, greatly enhancing the corrosion resistance.
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•A superhydrophobic surface with a 167.3° contact angle was fabricated via electrolytic polishing and 0.7-g/L MgCl2 solution etching followed by Perfluorooctyltriethoxysilane modification, featuring a typical nanosheets-composed petal-like morphology.•The corrosion current density of the superhydrophobic surface decreased by more than 2 orders, and corrosion inhibition efficiency is 99.67%.•The superhydrophobic surface is hardly attacked by chloride ions and avoids the generation of chloride ion channels.
In this study, we prepared a micro-nano hierarchical structure superhydrophobic 7055 aluminum alloy surface. The preparation mechanism, the surface topographies, the wettability, and the chemical compositions were characterized and discussed in detail. Results show that electrolytic polishing (EP) and etching can effectively inhibit the continuous growth of corrosion products and take grains as a unit, which has micron petal-shaped structures with the grain boundary as the boundary. The surface has a great lasting quality and the corrosive ions and liquids can hardly infiltrate the aluminum substrate and avoid the generation of chloride ion channels.
Effects of Ag addition on the age hardening and precipitation behavior of aluminum alloy 7075 were investigated. The transmission electron microscopy (TEM) and atom probe tomography (APT) were used ...to study the aggregate distribution and identify the role of Ag in precipitation hardening of the alloy. The hardness and strength of the Ag–containing alloy were increased by more than 10% due to a higher number density of fine aggregates, which was 2.5 times that of the Ag–free alloy 7075. Both T–type and η–type precipitates existed in the alloys, and two precipitation sequences occurred simultaneously as: SSS → η–type cluster → GP zone → η′ → η → T, and SSS → T–type cluster → GP zone→ T′ → T. Particularly, Ag promoted the formation of T–type clusters due to the interaction among Ag, Mg and Zn atoms as well as vacancies at the early stage of aging. The Mg–Ag, Zn–Ag, and vacancy–Ag co–clusters acted as nucleation sites for the subsequent precipitates (η′, T′, etc.). This also caused the increase of Mg concentration in T–type clusters at the beginning of aging and the narrowing of the precipitation free zone (PFZ) near grain boundaries at the peak aging.
•Ag accelerates the aging precipitation process of the alloy 7075.•The peak-aged alloy 7075 + Ag exhibits higher mechanical properties.•Ag increases the number density of aggregates in aged 7075 alloy.•Both T/η-types precipitates exist in the alloys 7075 and 7075 + Ag during aging.•Strong interacts of Mg–Ag/vacancy promote precipitation of T in alloy 7075 + Ag.
Physics learning contains mathematical processes with various equations to interpret concepts or phenomena in the quantitative concept. Each material with different values owns material mechanical ...properties such as elasticity. Spreadsheets can help mathematical processes become more effective and efficient. The output of spreadsheets can be interpreted as graphs or diagrams that make it easier to understand concepts and compare the elasticity of each material. The material studied in this study is an aluminum alloy in terms of its elemental content. Spreadsheet analysis presents the values of the elasticity properties of each material in graphical form. The elasticity properties studied are the modulus of elasticity (Young modulus), yield strength (Yield strength), and maximum strength (Ultimate strength).
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