Papers by Author: Mosbah Zidani

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Authors: Fyaçal Baira, Mosbah Zidani, Hichem Farh, Salim Messaoudi, Toufik Ziar, Anne Laure Helbert, Thierry Baudin
Abstract: Copper destined for electrical cabling require a compromise of mechanical properties and electrical resistivity. The drawing process accompanied by the formation of crystalline defects, such as gaps and dislocations, which leads to the increase in hardness, and therefore to the increase in resistivity, a very important characteristic for the conductivity and the efficiency of the cable. The scope of this work is to investigate the phenomenon of deformation texture evolution while copper wire drawn destined for electric cable-making and to understand its relationship with the electrical conductivity. In this study, we notice that the hardness and the resistivity increase with an increase of the deformation level. On the other hand, a slight decrease in the resistivity of the wires was observed after a holding time of 30 min at 260°C. The annealing of wires at 260°C for 9 min of holding time leads to a recrystallisation especially for high deformations and a gradual return of the mechanical properties and of the microstructure towards a state close to the state of the wire rod with the extension of time . The recrystallization texture is composed of the same components as the drawing texture, fibers <111>//ND (Normal Direction) and <001>//ND. The decrease in the intensity of the fiber after annealing is observed. On the other hand, the fiber <001> // ND remains stable.
Authors: Karim Djemmal, Hichem Farh, Rebai Guemini, Mosbah Zidani, Fares Serradj
Abstract: AlMgSi alloys (6XXX series) provide a good strength due to the precipitation of β” and β (Mg2Si) phases. They have also very good formability which is required for different forming process after appropriate heat treatments.This work was carried out to investigate the effect of the addition of copper and the excess of Si on the response of natural and artificial aging of two Al-Mg-Si alloys. The aging parameters on precipitation sequence of two Al-Mg-Si alloys with and without excess Si were studied by DSC, MET and Vickers hardness measurement. The combined effect of Cu, Fe and excess of Si was found to accelerate the precipitation of the hardening phases. The additions of copper to the AlMgSi refine the average of the grain size and have a greater hardening effect compared to the excess silicon addition.
Authors: Lahcene Mebarki, Mosbah Zidani, Said Mechachti, Hichem Farh, Djamel Miroud
Abstract: The present work aims at determining the effects of Nickel addition on the phase’s distribution in sintered part. It aims equally at identifying the effect of such addition on the microstructure and the mechanical properties. The addition to mixtures of alloying elements in their primitive form can lead to the formation of a heterogeneous microstructure in the sintered parts produced by the powder metallurgy (PM) process. It has been proved that the addition of nickel to an iron powder mixture forms nickel-rich areas (NRA) in the sintered parts. This is basically related to the low diffusion rate of nickel in iron at conventional sintering temperatures.
Authors: Farida Khamouli, Mosbah Zidani, Hichem Farh, Adel Saoudi, L'hadi Atoui
Abstract: This paper studied the effects of cellulosic and basic flux on the chemical composition, microstructure, formation of inclusions and micro hardness of X42 steel SMAW welds. The commercialized chemical compositions of flux used are: E6010, E8010-P1 and E8018-G, with electrodes of low carbon content. Welding conditions are not constant. The microstructure of the fusion zone for each flux consists mainly of acicular ferrite. It is found that manganese increases in the fusion zones (C, B and A) respectively .The change in mass concentration of manganese is homogeneous through the three points with all the used flux. Regardless of the flux used, the non-metallic inclusions observed are of two types: white and black. The micro-hardness decreasing values were obtained in the fusion zones (C, B and A).
Authors: Mokhtar Bayarassou, Mosbah Zidani, Hichem Farh
Abstract: The objective of the present investigation is to study the changes in microstructures and mechanical properties during ageing and homogenization treatment of Al-Mg-Si alloy wire cold drawn at the different deformation in ENICAB (Biskra), destined for the transport of electric energy. And also to understand the phase formation during the cold drawing of Al-Mg-Si alloy wires, as well as the combined influence of the plastic deformation level and the influence of aging temperature. Wire section reduction shows a change in microstructure and texture. Characterization methods used in this work is: Optical Microscopy (OM), Scanning Electron Microscope (SEM) and X-ray diffraction.
Authors: Said Mechachti, Omar Benchiheub, Abdenabi Abidi, Noureddine Gherraf, Mosbah Zidani, Hichem Farh
Abstract: Powder metallurgy was mainly used to produce automobile parts such as beds self-lubricating bearings, and gear wheels. In order to investigate the effect of porosity on the mechanical and tribological properties of sintered steel, specimens with 10%, 20%, and 30% porosity were produced on samples of parallelepipedic form, with technical of iron powders that has been used in a large industrial area. Sintering was carried out at 1100 ° C for 2 hours in an argon atmosphere. Metallographic studies such as pore formation, saturated area, and the nitrided layer analyses were performed by microscopy and optical microscopy. It was found that the irregular pore formation tendencies increase with an increase in porosity (%). Furthermore, an increase in porosity has proven to decrease the mechanical properties and increase the wear trace area and the friction coefficient of sintered steel.
Authors: Adel Saoudi, Farida Khamouli, L'hadi Atoui, Mosbah Zidani, Hichem Farh
Abstract: The aim of this study is to model the distribution patterns of the different mechanical properties of a submerged arc welded pipeline steel API X70 and to investigate the relationship between Vickers hardness and other mechanical properties of API X70. In this study, serial mechanical properties of 70 pipes, formed by spiral submerged arc welding of high strength low alloy steel (HSLA) API X70, were measured in base metal and weldments. Four main statistical distributions: Normal, Log-normal, Weibull and smallest extreme value distributions were chosen to test the goodness of fit to the experimental data. As a result, normal and lognormal distributions can equally model the distribution patterns of the whole experimental data of studied mechanical properties except for the hardness and toughness of the base metal that can be approximated by Weibull and smallest extreme value distributions, respectively. Using the current data, a weak but statistically significant correlation is obtained only between the toughness of the fusion zone and the hardness of both the base metal and the heat affected zone. Consequently, the calculated regression models were unable to estimate impact toughness values based on future measures of Vickers hardness components.
Authors: Toufik Djimaoui, Mosbah Zidani, Mohamed Chaouki Nebbar, T. Abid, Hichem Farh, Anne Laure Helbert, Francois Brisset, Thierry Baudin
Abstract: The aim of the present work is to study the evolution of microstructure, texture and mechanical properties during drawing of mild steel wire of type F8Z used in the manufacture of welding electrodes TREFISOUD. It was found that the as received wire has a ferritic-pearlitic microstructure corresponding to an isotopic state (without texture). This microstructure is relatively heterogeneous in the wire section. On the other hand, after strong drawing structure appears relatively homogeneous, throughout the section of the drawn wire. Also the deformation process by drawing causes the hardening of wire as a function of deformation with a reinforcing component of the fiber texture <110> // ND (majority), typical for bcc materials. Characterization methods used in this work is: Optical microscopy (OM), Scanning Electron Microscopy (SEM), the Electron Back Scattered Diffraction EBSD, Vickers microhardness and the tensile tests.
Authors: Zakaria Boumerzoug, N. Lahraki, Mosbah Zidani
Abstract: The operation which allows reducing wire diameter is called wiredrawing. The wiredrawing principle is that of using the metal plasticity to reduce the wire diameter. Our study is based on wire steel containing 0.05 % carbon. The regular orientation of the grains (texture) caused by external stresses during the drawing process is observed. This texture causes a phenomenon of material consolidation. Two annealing temperatures were applied on deformed wires for modifying the structure and mechanical properties. The effects of drawing and thermal treatment on our material were studied by, scanning electron microscope, hardness measurements and X – ray diffraction.
Authors: Mosbah Zidani, Zakaria Boumerzoug, Denis Solas, Thierry Baudin
Abstract: In this work, the effect of the deformation, caused by cold wire drawing, on the microstructure and the texture of low carbon steel wire (0.06 wt % C) is examined. The combined influence of the deformation level and the recrystallization temperature on the development of new grains is studied for all wires. Isothermal tests of annealing allow the determination of the critical temperature of recrystallization estimated above 450°C. The temperature effect is studied below the eutectoid level, at 500°C, 600°C and 680°C. The appearance of a homogeneous recrystallization is noted over the section of the wire. The recrystallized grains keep the same orientation as the deformed grains. The expansion of time of annealing lead to recrystallization in the ferritic grains accompanied by a spheroidization of the lamellar pearlite. The kinetics of recrystallization and spheroidization are accelerated by increasing of annealing temperature and the deformation level. The experimental techniques used in this study are: the Scanning Electron Microscope (SEM), the Electron Back Scattered Diffraction (EBSD), the X-ray diffraction and Vickers microhardness.
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