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RISS 인기검색어
- 검색키워드
- 저자 : Ehsan Borhani (검색결과 3 건)
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In-Situ Synthesis of Aluminum Matrix Composite from Al–NiO System by Mechanical Alloying
Samaneh Mamnooni,Ehsan Borhani,Davoud Bovand 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6
In this paper, Al-based composites reinforced by Alumina and Al–Ni intermetallic compounds have been successfullyfabricated by mechanical alloying technique. The intermetallic phase, i.e., NiAl, NiAl3,Ni2Al3,as well as Alumina, wereformed in the aluminum matrix by in situ solid-state reactions between pure Al and NiO powders. The effects of NiO content(7–10–13 vol%) on the characteristics of the fabricated composites were examined, the hardness, wear properties, phaseconstituent, and composite microstructure with different NiO content in particular. The results showed that the addition ofNiO to Al increases the formation of Al–Ni system intermetallic compounds and enhance the surface hardness. Further, it isascertained that Al–10 vol% NiO nanocomposite has better wear properties in comparison with samples with 7 and 13 vol%NiO due to the better matrix integrity and reinforcement distribution in the Al matrix.
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Bahram Azad,Ehsan Borhani 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.2
This work is focused on the effect of pre-aging time on the properties of Al-2wt%Cu alloy processed by accumulative roll bonding (ARB) process. Following aged at 190 °C for 10 or 30 min, the samples were deformed up to a strain of 4.8 by the ARB process. The microstructure evolution was investigated by transmission electron microscope and electron backscattering diffraction analyzes. The results showed that the Al2Cu precipitates were formed with different sizes due to the different pre-aging times and the finer precipitates were more effective on the formation of high angle grain boundaries during the ARB process. The grain size of Aged-10 min and Aged-30 min specimens decreased to 400 nm and 420 nm, respectively, after 6 cycles of the ARB process. Also, the final texture after 6 cycles of the ARB process, shown in the {111} pole figure, were different depending on the starting microstructures. The mechanical properties of specimens were investigated by the Vickers microhardness measurements and the tensile tests. The results showed that the mechanical properties are affected by the starting microstructure. The mechanical properties of Aged-10 min specimen were different compared to Aged-30 min specimen due to the different size of the pre-existing precipitates. Although by continuing process, the precipitates were probably dissolved due to the heavy deformation.
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Majid Naseri,Mohsen Reihanian,Ahmad Ostovari Moghaddam,Davood Gholami,Mohammad Alvand,Ehsan Borhani,Evgeny Trofimov 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.2
This study examined mechanical properties of AA2024 alloy and its correlation between strain path and crystallographictexture. Accumulative roll bonding (ARB) and cross accumulative roll bonding (CARB) were used to severely deformAA2024 alloys. Electron backscatter diffraction (EBSD) studies demonstrated that nano/ultrafine grains were formed by thestrain routes after eight cycles. It was also found that the lamellar boundary spacing and the mean boundary spacing were~ 360 ± 10 nm and 845 ± 10 nm after eight ARB cycles. In contrast to the ARB, the CARB specimen had equiaxed microstructurescharacterized by grains with a size of 150 and 100 nm. The CARB processed specimen exhibited a mean misorientationangle of 41.83° and a fraction of high angle grain boundaries of 78%, these values were 34.57° and 67% for ARB treatedspecimen, respectively. It was observed that the evolved texture is greatly affected by the strain paths. The ARB processedspecimen revealed strong Copper {112} <111>, Dillamor {4 4 11} <11 11 8>, S {123} <634>, and Brass {011} <211>components. In contrast, the CARB processed specimen showed major texture with prominent Copper {112} <111>, Brass{011} <211>, Rotated Cube {001} <110>, S {123} <634>, and Goss {011} <100> components. In the CARB specimen, theGoss/Brass texture ratio was intensified and the mechanical properties were superior (tensile strength: 535 MPa, microhardness:182 HV, elongation: 11.9%) compared with the ARB processed specimen (tensile strength: 455 MPa, microhardness:145 HV, elongation: 9.2%). Further, the change in strain path did not significantly affect the intensity of Goss and Cubecomponents, ruling out any further recrystallization tendency.
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