Microstructural and Corrosion Characteristics of Al-Fe Alloys Produced by High-Frequency Induction-Sintering Process

A stable and high-energy aqueous aluminum based battery

Aqueous aluminum ion batteries (AAIBs) have received growing attention because of their low cost, safe operation, eco-friendliness, and high theoretical capacity. However, one of the biggest challenges for AAIBs is...

Machining of Inserts with PCD Cutting-Edge Technology and Determination of Optimum Machining Conditions Based on Roundness Deviation and Chip-Cross Section of AW 5083 AL-Alloy Verified with Grey Relation Analysis

This paper describes the important significance of cutting-edge technology in the machining of polycrystalline diamond (PCD) cutting inserts by comparing the evaluation criteria. The LASER technology of cutting-edge machining is compared with grinding and electrical discharge machining (EDM) technologies. To evaluate the data from the experiments, the Grey Relational Analysis (GRA) method was used to optimize the input factors of turning to achieve the required output parameters, namely the deviation of roundness and chip cross-section. The input factors of cutting speed, feed rate, depth of cut and corner radius were applied in the experiment for three different levels (minimum, medium and maximum). The optimal input factors for turning of aluminum alloy (AW 5083) were determined for the factorial plan according to Grey Relational Grade based on the GRA method for the multi-criteria of the output parameters. The results were confirmed by a verification test according to the GRA method and optimal values of input factors were recommended for the machining of Al-alloy (AW 5083) products. This material is currently being developed by engineers for forming selected components for the automotive and railway industries, mainly to reduce weight and energy costs. The best values of the output parameters were obtained at a cutting speed of 870 m/min, feed rate of 0.1 mm/min, depth of cut of 0.5 mm and a corner radius of 1.2 mm.

Mitigating Corrosion Effects of Ti-48Al-2Cr-2Nb Alloy Fabricated via Electron Beam Melting (EBM) Technique by Regulating the Immersion Conditions

The corrosion behavior of newly fabricated γ-TiAl alloy was studied using electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP) techniques. The γ-TiAl alloy was produced from powder with compositions of Ti-48Al-2Cr-2Nb processed using electron beam melting (EBM) technique. The corrosion behavior of the bulk alloy was investigated in 1 M HCl solution for different immersion times and temperatures. The experimental results suggest that the fabricated alloy exhibits good resistance to corrosion in acid solution at room temperature. The results also indicate that with an increase in immersion time and solution temperature, the corrosion potential (Ecorr) shifts to a higher positive value, resulting in an increase in corrosion current (jcorr) and consequently a decrease in the corrosion resistance (Rp) of the alloy.

Effect of Transition Elements on the Thermal Stability of Glassy Alloys 82Al-16Fe-2TM (TM: Ti, Ni, Cu) Prepared by Mechanical Alloying

In the present study, the thermal stability and crystallization behavior of mechanical alloyed metallic glassy Al₈₂Fe₁₆Ti₂, Al₈₂Fe₁₆Ni₂, and Al₈₂Fe₁₆Cu₂ were investigated. The microstructure of the milled powders was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The results showed remarkable distinction in thermal stability of the alloys by varying only two atomic percentages of transition elements. Among them, Al₈₂Fe₁₆Ti₂ alloy shows the highest thermal stability compared to the others. In the crystallization process, exothermal peaks corresponding to precipitation of fcc-Al and intermetallic phases from amorphous matrix were observed.

Glass-Forming Ability and Corrosion Resistance of Al88Y8-xFe4+x (x = 0, 1, 2 at.%) Alloys

The effect of iron and yttrium additions on glass forming ability and corrosion resistance of Al₈₈Y_8-xFe_4+x (x = 0, 1, 2 at.%) alloys in the form of ingots and melt-spun ribbons was investigated. The crystalline multiphase structure of ingots and amorphous-crystalline structure of ribbons were examined by a number of analytical techniques including X-ray diffraction, Mössbauer spectroscopy, and transmission electron microscopy. It was confirmed that the higher Fe additions contributed to formation of amorphous structures. The impact of chemical composition and structure of alloys on their corrosion resistance was characterized by electrochemical tests in 3.5% NaCl solution at 25 °C. The identification of the mechanism of chemical reactions taking place during polarization test along with the morphology and internal structure of the surface oxide films generated was performed. It was revealed that the best corrosion resistance was achieved for the Al₈₈Y₇Fe₅ alloy in the form of ribbon, which exhibited the lowest corrosion current density (j_corr = 0.09 μA/cm²) and the highest polarization resistance (R_p = 96.7 kΩ∙cm²).