The surface mechanical alloying (SMA) technique achieved high capacitances, improved capacitance (C) and dielectric permittivity (& epsilon;& PRIME;) of mixed Aluminum/fiber-glass 'Al/F-glass' formed on aluminum plates. The radiofrequency RF range 0.1-106 Hz was applied on the Al/F-glass on Al plates, acting as parallel electrodes sandwiching the mixed ceramic Al/F-glass as dielectric. Capacitance increase observed after surface alloying on treated Al with small 1.5 balls than 6 mm balls on Al-plate & 1 A l-plate 2 respectively, giving twice the permittivity constant of the annealed Al. Deformation micro-scale cavities in Al surfaces played important role in raising capacitance and permittivity values; Interpreted as condensers inside a condenser caused capacitance increase according Maxwell-Wagner-Sillars effect. Dielectric relaxation model Havriliak-Negami Model was used to examine the occurrence of the Maxwell-Wagner-Sillars effect in alloyed Al/F-glass surfaces on Al plates, which confirms micro-cavities important role due to pre-treatment of Al surfaces.

The behavior of Al2O3/Al composite coated Al electrodes fabricated by surface mechanical alloying ‘SMA’ was studied. The work was accomplished using Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques in alkaline media 2MKOH were done at room temperature. Results show hydroxyl ions accumulate on the surface due to Al deformation micro cavities filling with Al2O3 until full charge blockage reached. A barrier cover layer development causing an increase of both resistance and capacitance as it becomes more stable and thinner with exposure time increase. Migrating hydroxyl ion inside micro cavity changed its composition from Al2O3 to stable tetrahedral Al(OH)4− aluminate ions. Therefore future benefits could be reached by developing such surfaces having charge accumulation that enables environmental interaction.

We present terahertz spectroscopy study on spherical nanoparticles powder mixture of aluminum, alumina, and MWCNTs induced by surface mechanical attrition treatment (SMAT) of aluminum substrates. Surface alloying of AL, Al2O3 0.95% and MWCNTs 0.05% powder mixture was produced during SMAT process, where a compact surface layer of about 200 μm due to ball bombardment was produced from the mixture. Al2O3 alumina powder played a significant role in MWCNTs distribution on surface, those were held in deformation surface cites of micro-cavities due to SMAT process of Al. The benefits are the effects on resulted optical properties of the surface studied at the terahertz frequency range due to electrical isolation confinement effects and electronic resonance disturbances exerted on Al electronic resonance at the same range of frequencies. THz acoustic phonon around 0.53-0.6THz (17-20cm-1) were observed at ambient conditions for the spherical nanoparticles powder mixture of Al, Al2O3 and MWCNTs. These results suggested that the presence of Al2O3 and MWCNTs during SMAT process leads to the optically detection of such acoustic phonon in the THz frequency range.

THE CORROSION resistance of Aluminum (Al) in 3.5% NaCl was improved after surface mechanical attrition treatment (SMAT). Cyclic potentiodynamic polarization (CPP) measurements have shown hysteresis's loop area owing to localized attack. Surface examinations using scanning electron microscopy (SEM), electron dispersive X-ray (EDX), X-ray diffraction (XRD) and grazing induced X-ray diffraction (GIXRD) have been used to investigate changes of composition on the surface at different depths. The result of polarization shows that as increasing the time of annealing before 10 min SMAT the surface of Al becomes more resistance and behaves similar to that of adding cathodic inhibitor. The study was carried out also for the annealed samples after different time of SMAT 0, 5, 10, 15, 20 and 25 min. proved that the corrosion resistance was improved with increasing the time till 15 min treatment and decreased again after that. CPP experiments at all the time except at 15 min SMAT recorded the formation of different steps at different potential after the corrosion potential. The steps are similar to that recorded due to formation of protective film and the break down due to pitting corrosion. GIXRD proved that the appearance of these steps is due to the formation of different metallic and intermetallic solid solution phases which have different corrosion potential. On the other hand the more corrosion resistance of 15 min SMAT was attributed to the formation of the most anodic phase of Al-39 Cu-47. The dissolution of the treated SMAT Al in 3.5 % NaCl are localized attack and mainly intergalvanic corrosion where its rate depends on the defence between the corrosion potential of the phases recorded and the Al substrate.

THE CORROSION rate of Al in 3.5 % NaCl at room temperature can be reduced by subjecting the metal to sever plastic deformation (SPD) through the procedure of surface mechanical attrition treatment (SMAT). The corrosion resistance of grain refined Al in 3.5% NaCl by SMAT for 5, 10, 15, 20 and 25 min in comparison with Al as rolled(0) and after annealing for 5 hr at 600 degrees C (blank) was investigated by open circuit potential measurement. The results show that as increasing the time of SMAT up to 15min, the steady state potential (Est.) shifted to less negative values. In contradiction, further increasing the time to 20 and 25 min, the potential returned to more negative values. Surface examination using scanning electron microscope (SEM), electron dispersive X-ray (EDX) and X-ray diffraction (XRD) proved that the above results are controlled by the time of oxide film formation. This depends on different factors such as the grain refinement, the segregation of Fe to the outer surface, the formation of micro cavities, the crystallographic orientation and habit Al (111) plane phases.

Al-11 wt.% Si-11 wt.% Cu (11.29 at.% Si-5.1 at.% Cu) melt was rapidly solidified into ribbons and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and microhardness technique. The Rietveld X-ray diffraction analysis was applied successfully to analyze the microstructure and phase precipitations. The high cooling rate obtained in rapid solidification has a significant influence on the microstructure and microhardness of this alloy. On the basis of the Al peaks shift measured in the XRD scans, a solid solubility extension value of 3.95 at.% Si and 3.54 at.% Cu in α-Al were determined. No XRD peaks of the Si phase have been detected. XRD peaks of the intermetallic Al 2 Cu phase have been observed clearly with estimated content of 12.6 wt.%. During prolonged annealing process at 350°C/25 h, XRD peaks of the Si phase clearly appeared with estimated content of 8.6 wt.% and, moreover, the Al 2 Cu phase content increased to 16 wt.%. The estimated crystallite size and micro-strain % of α-Al are 30 nm and 0.056, respectively. The melt-spun wheel side ribbon represents ultra-fine microstructure with particles size less than 1μm and exhibits enhancement of hardness to 241 HV. Hardness has further increased to 291 HV during heat treatment (150°C/12 h). Rapid solidification exhibited a great influence on microstructure and microhardness of the Al-Si-Cu alloy.

Al-11 wt.% Si-11 wt.% Fe (11.29 at.% Si-5.6 at.% Fe) melt was rapidly solidified into ribbons and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and microhardness technique. The Rietveld X-ray diffraction analysis was applied successfully to analyze microstructure and phase precipitations. On the basis of the aluminum peak shifts measured in the XRD scans, a solid solubility extension value of 1 at.% Si in α-Al was determined. SEM investigations confirmed presence of a spherical shape α-phase particles in addition to needle and spherical shape β-phase particles with contents of 1.1 wt.% and 10.1 wt.% as deduced by XRD analysis. During prolonged annealing process at 350°C/25 h, α-phase disappeared, β-phase content increased to 30 wt.%, and Si presence becomes more evident as deduced by XRD analysis. EDS analysis confirmed that these β particles observed in the as-melt spun alloy are of lower Fe content comparing to those usually observed in the as-cast counter-part alloy. Besides, the length distribution of needle shape β-particles has been shortened to be diverse from 1 to 5 μm. The as-melt spun ribbons exhibited enhancement of hardness to 277 HV and further increased during heat treatment (150°C/12 h) to 450 HV. This improvement of microstructure and hardness are the influence of microstructural refinement and modification obtained during the rapid solidification process.

Physical vapor deposited Al/Ru bi-layers on silicon substrates have been annealed to study reactions development.Temperature induced changes after increasing time from 10 to 2880 min in vacuum annealing at 500 o C were studied.Grazing incidence X-ray Diffraction indicates RuAl 2 phase formation in all samples.Electron diffraction pattern of a thin foil extracted from annealed bilayers shows spots for RuAl 2 and Al 6 Ru phases.Focused ion beam cross sections, shows non-uniform 500 nm thickness reaction layer at the Al/Ru interface.Decreasing thickness at a fixed ratio of Ru/Al = 1.224 reduces the time required to start reaction at the same temperature.Formed intermetallic phase layer acts as a diffusion barrier that controls further atomic diffusion from both Al and Ru sides into the formed reaction layer.