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Significant improvements in mechanical properties of AA5083 aluminum alloy using dual equal channel lateral extrusion

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Transactions of Nonferrous Metals Society of China 2016年第12期26卷 3081-3090页

作者： N.fAKHAR f.fereshteh-saniee R.MAHMUDI Department of Mechanical Engineering Faculty of EngineeringBu-Ali Sina University School of Metallurgical and Materials Engineering College of EngineeringUniversity of Tehran

Dual equal channel lateral extrusion (DECLE), as a severe plastic deformation (SPD) process, was employed forimproving the mechanical properties of AA5083 aluminum alloy. Several experiments were conducted to study the influences of theroute type, namely A and B, and pass number on mechanical properties of the material. The process was conducted up to 6 passeswith decreasing process temperature, specifically from 573 to 473 K. Supplementary experiments involving metallography, hardnessand tensile tests were carried out in order to evaluate the effects of the process variables. The hardness measurements exhibitedreasonably uniform distributions within the product with a maximum increase of 64% via a 6-pass operation. The yield and ultimatestrengths also amended 107% and 46%, respectively. These significant improvements were attributed to the severe shear deformationof grains and decreasing pass temperature, which intensified the grain refinement. TEM images showed an average grain sizereduction from 100 μm for the annealed billet to 200 nm after 6 passes of DECLE. finally, the experimental findings for routes A andB were compared and discussed and some important conclusions were drawn.

关键词： AA5083 aluminum alloy severe plastic deformation dual equal channel lateral extrusion hardness homogeneity

Production of AZ80/Al composite rods employing non-equal channel lateral extrusion

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Transactions of Nonferrous Metals Society of China 2016年第5期26卷 1276-1283页

作者： Mohammad ASGARI faramarz fereshteh-saniee Mechanical Engineering Department Faculty of Engineering Bu-Ali Sina University

In order to simultaneously take the advantages of magnesium and aluminum alloys, AZ80/A1 composite rods were produced using non-equal channel lateral extrusion （NECLE） process at different temperatures. Scanning electron microscope （SEM） and energy dispersive spectrometer （EDS） tests as well as the shear punch test were employed to study the quality and strength of the bond between the two alloys. It was found that the process temperature was an important factor affecting the level of interfacial bonding, such that increasing the temperature from 250 to 300℃ has improved the strength by 37% and the thickness of the bond between the layers by 4.5%. Moreover, this temperature rise reduced the maximum required forming load by 13%. However, the hardness tests showed that this increase in the process temperature resulted in 4% decrease in the hardness of the composite bar.

关键词： bimetallic composite magnesium alloy aluminum alloy mechanical properties co-extrusion welding non-equal channel lateral extrusion

Influence of roll speed difference on microstructure, texture and mechanical properties of 7075 aluminum plates produced via combined continuous casting and rolling process

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Transactions of Nonferrous Metals Society of China 2021年第4期31卷 901-912页

作者： Mohammad Mehdi AMIRI faramarz fereshteh-saniee Department of Mechanical Engineering Faculty of EngineeringBu-Ali Sina UniversityHamedan 65178Iran

The influences of the dissimilarity in the roll speeds on the microstructure, texture and mechanical properties of 7075 aluminum plates produced via combined continuous casting and rolling(CCCR) process were investigated. Several experiments were conducted with three different upper/lower roll rotational speed ratios(ω/ω0, ω is the upper roll rotational speed and ω0 is the lower roll rotational speed), namely 1:1, 1:1.2 and 1:1.4. It was found that the greatest dissimilarity in the roll speed(ω/ω0=1:1.4) improved the yield strength and ultimate tensile strength of 7075 Al plate in the rolling direction by 41.5% and 21.9%, respectively. Moreover, at a roll speed ratio of ω/ω0=1:1.4, the average grain size was decreased by 36% whereas the mean hardness of the transverse cross-section of the finally rolled plate was increased by about 9.2%. Texture studies also revealed that the more the difference in the roll speeds was, the greater the isotropy and the hardness of the final product were. Nevertheless, conducting CCCR operation with different roll speeds resulted in about 6% reduction in the elongation of the deformed plate.

关键词： continuous casting and rolling 7075 Al alloy roll speed difference microstructure mechanical properties texture anisotropy

Effects of die geometry on non-equal channel lateral extrusion(NECLE) of AZ80 magnesium alloy

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Transactions of Nonferrous Metals Society of China 2014年第10期24卷 3274-3284页

作者： faramarz fereshteh-saniee Mohammad ASGARI Mahmoud BARATI Sayed Mahmoud PEZESHKI Mechanical Engineering Department Faculty of Engineering Bu-Ali Sina University Applied Mechanics Department Faculty of Mechanical Engineering K.N. Toosi University of Technology

Non-equal channel lateral extrusion（NECLE） is a new process that can be used to attain higher grain refinement in comparison with equal channel lateral extrusion（ECLE）. The die design for this process was numerically and experimentally studied. After finding a good correlation between the numerical and experimental results, more comprehensive fE analyses were carried out. Different die geometrical parameters were considered and their effects on the induced plastic strain, stress distribution, velocity field and forming load of the process were investigated. It was found that by this process with a suitable set of die geometrical parameters, higher induced effective strain and more homogeneous strain distribution could be achieved in comparison with ECLE operation.

关键词： magnesium alloy non-equal channel lateral extrusion(NECLE) die geometry homogeneity arbitrary Lagrangian-Eulerian(ALE) method

Candida accommodates non-culturable Helicobacter pylori in its vacuole-Koch's postulates aren't applicable

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World Journal of Gastroenterology 2018年第2期24卷 310-314页

作者： farideh Siavoshi Parastoo saniee Department of Microbiology School of Biology University College of Sciences University of Tehran Department of Microbiology and Microbial Biotechnology Faculty of Life Sciences and Biotechnology Shahid Beheshti University G.C.

The following are the responses to the "letter to the editor"("Helicobacter is preserved in yeast vacuoles! Does Koch's postulates confirm it?") authored by Nader Alipour and Nasrin Gaeini that rejected the methods, results, discussions and conclusions summarized in the review article authored by Siavoshi f and saniee P. In the article, 7 papers, published between 1998 and 2013, were reviewed. The 7 papers had been reviewed and judged very carefully by the assigned expertise of the journals involved, including the reviewers of the World Journal of Gastroenterology(WJG), before publication. In the review article, 121 references were used to verify the methods, results and discussions of these 7 papers. The review article was edited by the trustworthy British editor of the(WJG), and the final version was rechecked and finally accepted by the reviewers of(WJG). None of the reviewers made comments like those in this "letter to the editor", especially the humorous comments, which seem unprofessional and nonscientific. Above all, the authors' comments show a lack of understanding of basic and advanced microbiology, e.g. bacterial endosymbiosis in eukaryotic cells. Accordingly, their comments all through the letter contain misconceptions. The comments are mostly based on personal conclusions, without any scientific support. It would have been beneficial if the letter had been reviewed by the reviewers of the article by Siavoshi and saniee.

关键词： Helicobacterpylori Intracellular occurrence Candida yeast 16S DNA detection