scholarly journals INCREASING THE INFILTRATION ABILITY OF ALUMINUM ALLOY FOR IMPREGNATION IN A NON-AUTOCLAVE METHOD

Author(s):  
V. A. Gulevsky ◽  
N. Yu. Miroshkin ◽  
S. N. Tsurikhin ◽  
N. A. Kidalov

An increase in the efficiency of gas-free impregnation of a porous carbon-graphite frame to aluminum alloys by applying thin electroplated metal alloying coatings to the surface of the pores of a carbon-graphite sample by electrochemical method is investigated. It is shown that the preliminary deposition of such coatings makes it possible to obtain alloying with highly pure elements, increasing the filling of pores with matrix melt at impregnation temperature (800 ° C).

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Dmitry V. Dzhurinskiy ◽  
Stanislav S. Dautov ◽  
Petr G. Shornikov ◽  
Iskander Sh. Akhatov

In the present investigation, the plasma electrolytic oxidation (PEO) process was employed to form aluminum oxide coating layers to enhance corrosion resistance properties of high-strength aluminum alloys. The formed protective coating layers were examined by means of scanning electron microscopy (SEM) and characterized by several electrochemical techniques, including open circuit potential (OCP), linear potentiodynamic polarization (LP) and electrochemical impedance spectroscopy (EIS). The results were reported in comparison with the bare 6061-O aluminum alloy to determine the corrosion performance of the coated 6061-O alloy. The PEO-treated aluminum alloy showed substantially higher corrosion resistance in comparison with the untreated substrate material. A relationship was found between the coating formation stage, process parameters and the thickness of the oxide-formed layers, which has a measurable influence on enhancing corrosion resistance properties. This study demonstrates promising results of utilizing PEO process to enhance corrosion resistance properties of high-strength aluminum alloys and could be recommended as a method used in industrial applications.


2019 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
Mahmoud Alasad ◽  
Mohamad Yahya Nefawy

The aluminum alloys of the 7xxx series consist of Al with Zn mainly, Mg and Cu. 7xxx aluminum alloys has high mechanical properties making it distinct from other aluminum alloys. In this paper, we examine the effect of adding Nickel and heat treatments on the microstructure and hardness of the 7075 aluminum alloy. Were we added different percentages of nickel [0.1, 0.5, 1] wt% to 7075 Aluminum alloy, and applied various heat treatments (artificial aging T6 and Retrogression and re-aging RRA) on the 7075 alloys that Containing nickel. By applying RRA treatment, we obtained better results than the results obtained by applying T6 treatment, and we obtained the high values of hardness and a smoother microstructure for the studied alloys by the addition of (0.5 wt%) nickel to alloy 7075.


Author(s):  
Khaleel Abushgair

Purpose. To conduct an experimental study on M102 aluminum alloy bulk content characterization under cyclic loadings for precision applications such as balance machines, optical, and laser instruments. M102 (AL-C-O) dispersion-reinforced aluminum alloy was chosen because of its ability to withstand temperatures beyond 200C and has a better strength than precipitation-hardened Al alloys at room temperature. A CNC milling machine is used to manufacture test samples with longitudinal machining directions. A constant time interval is set for the fabric a quarter-hour span, which is based on the investigation of inelastic and plastic deformations in the nanoscale. Methodology. An electromagnetic test instrument applies a tensile stress range of 10 to 145 N/mm2 to samples with particular shape. It should be noted that interferometers and capacitive sensors were used to measure all forms of deformations with and without loading. The experiments are carried out in a temperature-stable environment of 30.5 C; measurements are taken within a residual strain range of 10 microns. Findings. The results obtained show that results for inelastic deformations for samples of longitudinal cuts direction at 30.5 C were measured under 150 N/mm2 stress as 500 nm inelastic deformation and 100 nm plastic deformation were measured, which is much higher than aluminum alloy studied before at room temperature (20 C). Furthermore, it was found that the time constant of the M102 (ALCO) aluminum alloy samples was double times higher than that for other samples, Originality. For the first time, a study has been conducted on inelastic and plastic deformations in the nanoscale for characterization of M102 aluminum alloy bulk content under cyclic loadings for precision applications. Practical value. One of the main factors affecting the using of other materials than steel in precision applications such as balance machines, optical, and laser instruments is measurement and determination of inelastic, plastic and time constant of the process of delamination of materials of different aluminum alloys since they are nonmagnetic, are easily machined and shaped. This will bring new products and opportunities for these materials.


2013 ◽  
Vol 662 ◽  
pp. 251-257
Author(s):  
Ning Xia ◽  
Zhi Min Zhu ◽  
Hui Chen

6005A aluminum alloys were welded at different relative humidity conditions. The effects of relative humidity on the salt fog corrosion of the welding joints were researched. The results showed that the weight loss of the joints after 14 days corrosion was higher than that corroded after 7days, but the corrosion rate was lower. The corrosion rate first increased then declined with the increase of environmental humidity for the joints corroded for 7days. However, when the environmental humidity was 80%, corrosion rate achieved the maximum, when environment humidity was 70%, corrosion rate was the lowest. After corroded for 14 days, corrosion rate was the maximum when the environmental humidity was 50%, and it was the lowest when the environmental humidity was 90%. The tensile strength declined obviously after corrosion.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Arun M. ◽  
Muthukumaran M. ◽  
Balasubramanian S.

Purpose Dissimilar materials found applications in the structural fields to withstand the different types of loads and provide multi-facet properties to the final structure. Aluminum alloy materials are mostly used in aerospace and marine industries to provide better strength and safeguard the material from severe environmental conditions. The purpose of this study is to develop new material with superior strength to challenge the severe environmental conditions. Design/methodology/approach In the present investigation, friction stir welding (FSW) dissimilar joints were prepared from AA6061 and AA5083 aluminum alloys, and the weld nugget (WN) was reinforced with hard reinforcement particles such as La2O3 and CeO2. The tribological and mechanical properties of the prepared materials were tested to analyze the suitability of material in the aerospace and marine environmental conditions. Findings The results showed that the AA6061–AA5083/La2O3 material exhibited better mechanical and tribological characteristics. The FSW dissimilar AA6061–AA5083/La2O3 material exhibited lower wear rate of 7.37 × 10−3 mm3/m and minimum friction coefficient of 0.31 compared to all other materials owing to the reinforcing effect of La2O3 particles and the fine grains formed by FSW process at WN region. Further, FSW dissimilar AA6061–AA5083/La2O3 material displayed a maximum tensile strength and hardness of 378 MPa and 118 HV, respectively, among all the other materials tested. Originality/value This work is original and novel in the field of materials science engineering focusing on tribological characteristics of friction stir welded dissimilar aluminum alloys by the reinforcing effect of hard particles such as La2O3 and CeO2.


Author(s):  
Aygen A Erdoğan ◽  
Erol Feyzullahoğlu ◽  
Sinan Fidan ◽  
Tamer Sinmazçelik

AA6082-T6 aluminum alloys are widely used in various applications in automotive and aircraft industries. They offer an attractive combination of surface properties, strength and corrosion resistance. The structural components manufactured by AA6082-T6 aluminum alloys can be exposed to impingement of solid particles throughout their service life. In this study, erosive wear behaviors of AA6082-T6 aluminum alloy were investigated. For the evaluation of erosive wear induced by solid particle impacts, a detailed study was conducted on AA6082-T6 aluminum alloy by using aluminum oxide (Al2O3) erodent particles. Two different particles were used in solid particle erosion tests, which are 60 mesh (212–300 µm) and 120 mesh (90–125 µm), respectively. Also, the aluminum alloy samples were tested under two different air pressures (1.5 bar and 3 bar). The erosive wear tests were carried out according to ASTM G76 standard at six various impact angles (15°, 30°, 45°, 60°, 75°, 90°). The surface roughness and morphology of worn samples were analyzed by using a non-contact laser profilometer. It was found that erodent particle size affected the surface erosion damage, erosion rate, crater morphology and roughness. The eroded surfaces of specimens were analyzed by SEM. The surfaces of specimens were also investigated by using EDS in SEM studies.


2019 ◽  
Vol 9 (6) ◽  
pp. 1191 ◽  
Author(s):  
Mengmeng Li ◽  
Alexey Lomonosov ◽  
Zhonghua Shen ◽  
Hogeon Seo ◽  
Kyung-Young Jhang ◽  
...  

Nonlinear acoustic techniques are established tools for the characterization of micro-inhomogeneous materials with higher sensitivity, compared to linear ultrasonic techniques. In particular, the evaluation of material elastic quadratic nonlinearity via the detection of the second harmonic generation by acoustic waves is known to provide an assessment of the state variation of heat treated micro-structured materials. We report on the first application for non-destructive diagnostics of material thermal aging of finite-amplitude longitudinal acoustic pulses generated and detected by lasers. Finite-amplitude longitudinal pulses were launched in aluminum alloy samples by deposited liquid-suspended carbon particles layer irradiated by a nanosecond laser source. An out-of-plane displacement at the epicenter of the opposite sample surface was measured by an interferometer. This laser ultrasonic technique provided an opportunity to study the propagation in aluminum alloys of finite-amplitude acoustic pulses with a strain up to 5 × 10−3. The experiments revealed a signature of the hysteretic quadratic nonlinearity of micro-structured material manifested in an increase of the duration of detected acoustic pulses with an increase of their amplitude. The parameter of the hysteretic quadratic nonlinearity of the aluminum alloy (Al6061) was found to be of the order of 100 and to exhibit more than 50% variations in the process of the alloy thermal aging. By comparing the measured parameter of the hysteretic quadratic nonlinearity in aluminum alloys that were subjected to heat-treatment at 220 °C for different times (0 min, 20 min, 40 min, 1 h, 2 h, 10 h, 100 h, and 1000 h), with measurements of yield strength in same samples, it was established that the extrema in the dependence of the hysteretic nonlinearity and of the yield strength of this alloy on heat treatment time are correlated. This experimental observation provides the background for future research with the application goal of suggested nonlinear laser ultrasonic techniques for non-destructive evaluation of alloys’ strength and rigidity in the process of their heat treatment.


2015 ◽  
Vol 792 ◽  
pp. 174-179
Author(s):  
Mikhail Pervukhin ◽  
Mikhail Kuchinskii

The paper presents the basics of the technology for rapid crystallization of aluminum alloys in electromagnetic field. It is shown that the ingots produced with the stated technology have even microstructure and improved physical and mechanical characteristics.


2007 ◽  
Vol 561-565 ◽  
pp. 1653-1656
Author(s):  
Yoshitaka Iwabuchi ◽  
Isao Kobayashi

This research article describes the newly developed composite material using the artificial pellets made of incineration ashes and recycled aluminum alloys. The factor affecting its various properties was investigated and discussed. Through trial and error, the hybrid preform with good soundness and preferable dispersion of the pellets could be obtained. The density and compression strength and thermal conductivity were measured in comparison of other structural materials.


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