Sciences et génie des matériaux

Nombre total de résultats : 67
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Modal Analysis For Composite Sandwich Plates Of Honeycomb Core

Gaagaia, Guenanou, Ahmed Belaadi, Aouaichia, Bouakba, Fergani (2018)
Article de conférence

.The purpose of this work is to realize a vibratory study on panel’s sandwiches established by the honeycomb core and aluminum skins, used in the conception of the aerospace structures; all the analyses are based on conditions in the embedded free limits (E-L-L-L). The aim is to compare the natural frequencies of the two plates with those obtained from the two simulation models. Two methods are used in modeling, 3D drawing of the sandwich structures and calculating an equivalent structure using the homogenization method based on representative elementary volume (REV) using ANSYS software. The modal resolution of these two configura-tions is performed by the finite element method. The comparison of numerical results shows excellent agreement.Voir les détails

Mots clés : Sandwich plate, homogenization, FRF's, modal analysis, Finite element method.

Extraction of green inhibitor and study of their antioxidant effectiveness of ecologicalcorrosion

Souad brick chaouche, Haddad Ahmed (2017)
Article de conférence

Several methods are available to prevent or retard corrosion ofmetallic materials, the use of inhibitors is one of the besttechnique to ensure their protection in contact with aggressivemedia such as hydrochloric acid medium. The environmentaltoxicity of organic corrosion inhibitors has prompted thesearch for green corrosion inhibitors as they are biodegradable,do not contain heavy metals or other toxic compounds. As inaddition to being environmentally friendly and ecologicallyacceptable, plant products are inexpensive, readily availableand renewable. The objective of this work is the extraction oflimonene from orange peels and study their effectiveness onthe corrosion of X42 steel in HCl medium. The analysis ofinhibitor was evaluated by chemical methods, and theelectrochemical study shows that the addition of limonene tothe medium induces a reduction in the corrosion rate of thesteel in HCl medium. Other parameters may influence itsinhibitory activity such as immersion time, concentration ofinhibitor, the nature of media (acidic or basic).Voir les détails

Mots clés : Metal and alloys; Acid medium; corrosion inhibitors; Green inhibitors; limonene

EVALUATION OF MECHANICAL STRESS EFFECT ON THE PROPERTIES OFSTAINLESS STEEL SURFACES BY SECM, SKP, SVET AND LEIS

Ahmed HADDAD, ZIOUCHE Aicha, Yahi sara, Souad brick chaouche (2017)
Article de conférence

Mechanical stress or fatigue cracks originate from varioussurface imperfections, such as inclusions, pits, or residualstress. It is very important to use a method to predict thelikelihood of environment-assisted cracking or pitting corrosion.The austenitic stainless steel shows high corrosionresistance level. It knows that plastic deformation decreaseit's resistance. The corrosion form in case of this steel is veryspecial and the corrosion tests are difficult. The investigationof Scanning Kelvin Probe (SKP), s canning vibrationelectrode technique (SVET) and localized electrochemicalimpedance spectroscopy (LEIS) to evaluate the influence ofmechanical stress on the electrochemical properties ofaustenitic stainless steel 316L.We tested the selected steel about its corrosion behaviour afterhigh rate deformation. We wanted to find a relationshipbetween the corrosion resistance decreasing and the rate ofthe plastic deformation. Plastic deformation effect of thecorrosion resistance in case of austenitic stainless steelVoir les détails

Mots clés : SKP, SVET, LIES, corrosion, austenitic, plastic deformation 316

Comparative study on the microstructural and mechanical properties of WC-Co/AISI 1020 steel brazed joint obtained by TIG and oxyacetylene process

Billel CHENITI, Djamel Miroud, Pavol Hvizdos, Brahim BELKESSA, Bouzid MAAMACHE, Djilali Allou. (2018)
Article de conférence

In this work, the microstructural evolution and the mechanical properties of WC-Co / AISI 1020 steel brazed joint obtained by oxyacetylene and Tungsten Inert Gas (TIG) brazing process are investigated. The maximum peak temperature induced by TIG process and the introduction of a shielding gas cause a remarkable diffusion of Co and rearrangement of WC particles along the interface with the filler alloy. The Energy Dispersive Spectroscopy (EDS) analysis reveals that the inter-diffusion activity of elements across the interfaces especially Co and Ni is more important using TIG process compared to oxyacetylene process The mechanical behavior is carried out through micro-hardness measurements and toughness tests using Vickers Indentation fracture method on the WC-Co along the parallel line of the interface with the filler alloy. The results show that the brazed joint issued from TIG process becomes increasingly hard and brittle when approaching the WC-Co/braze interface and loses its toughness (7 MPa/m1/2 compared to 15 MPA/m1/2 for oxyacetylene process) with increasing the brazing temperature.Voir les détails

Mots clés : WC-Co cermet, TIG brazing, Oxyacetylene brazing, Interface, Fracture toughness

CORRÉLATION ENTRE LES PROPRIÉTÉS STRUCTURALES ET OPTIQUES D'ALN / MN TRAITÉES PAR PULVÉRISATION CATHODIQUE PAR MAGNÉTRON D.C.

K. CHETTAH, W. RICHI, A. Guenanou, D. ZELMATI, I. Attoui, H. Hazourli, N. Redjdal (2018)
Article de conférence

Dans ce travail, nous présentons une étude de l'effet de l'addition de Mn sur les propriétés structurales et optiques des couches minces AlN / Mn préparées par pulvérisation DC magnétron et déposées sur des substrats Si (100) et étudiées par spectroscopie Raman, MEB et Spectroscopie UV-Visible. L’analyse Raman a permis de déterminer trois modes vibratoires attribués à la phase Wurtzite: A1 (TO); E1 (TO); E2 (haut) et le mode vibration local (MVL) associé à l'addition de Mn. L’analyse par Microscopie à Balayage (MEB) a montré que deux structures distinctes avec une apparence de formes de nanoparticules de fleurs. Les analyses UV-Visible montrent que le coefficient de transmission (T%) diminue de 91 à 80% avec l'addition de Mn.Voir les détails

Mots clés : AlN couches mince;, Pulvérisation DC magnétron; Mode vibration local (MVL)

EFFET DE LA DECARBURATION DES PARTICULES DE WC SUR L’EVOLUTION MICROSTRUCTURALE ET LE COMPORTEMENT MECANIQUE DU RECHARGEMENT DUR WC-NI

B.cheniti, D.Miroud, P.Hvizdoš, B.Belkessa, Y.YAHMI, B.MAAMACHE, R.Badi (2018)
Article de conférence

Le but de ce travail est l’étude des techniques de fabrication des monoblocs des outils de forage en particulier la technique de rechargement dur (outil en corps acier) d’un acier (substrat) usiné. L’interface entre le substrat et le rechargement est une zone sensible, où la qualité de rechargement dépend de ses propriétés. Dans le but de garantir l’adhérence entre le rechargement et le substrat, nous avons introduit une couche d’accrochage afin de minimiser les tensions en réduisant l’écart du coefficient de dilatation thermique entre le substrat et le rechargement dur. Par ailleurs, des études ont été effectuées sur la caractérisation du WC dans une matrice à base de Ni et cela, en employant le procédés de revêtement (rechargement) oxyacétylénique. Le problème de la dissolution et la décarburation des particules de WC est bien traité dans notre travail et l’étude a montré son effet direct sur le comportement mécanique du rechargement.Voir les détails

Mots clés : WC-Ni, Hardfacing, Interface, Décarburation, propriétés mécaniques.

ACTION ET COMPORTEMENT DES REVETEMENTS ZEOLITIQUES SUR LA RESISTANCE A LA CORROSION D'ALLIAGES D'ALUMINIUM

NIBOU Djame, IDIR Brahim (2018)
Article de conférence

DES FILMS ZEOLITIQUES MINCE EST UNE CLASSE DE REVETEMENT INORGANIQUE ET ECOLOGIQUE, SONT PROPOSE COMME PROTECTION DES SURFACES METALLIQUES, EN RAISON DE LEUR NON TOXICITE,ET LEUR STABILITE THERMIQUE. LES DEPOTS DE ZEOLITES SYNTHETISES SE CRISTALLISENT IN SITU, OFFRE UNE STRATEGIE DE BOUCLIER CONTRE LA CORROSION DES METAUX.Voir les détails

Mots clés : Zéolite, revetement, Aluminium, corrosion

ELIMINATION DES POLLUANTS DES EAUX USEES URBAINE DE LA VILLE DE GUELMA PAR ELECTROCOAGULATION

Sana Chibani, Somia Chibani, Hadria Ferdenach, Zohra bechiche, Ammar Nemouchi, Ouahida Khireddine, Melek Bendjaballah, Mohamed El Hocine Benhamza (2018)
Article de conférence

Cette étude a pour but d’améliorer le rendement de traitement des eaux usées urbaines dela ville de Guelma par électrocoagulation. Dans ce travail et afin d’évaluer la technique d’électrocoagulation utilisée dans le traitement des eaux usées ; plusieurs principaux paramètres à savoir le type des électrodes, le potentiel appliqué et le temps de réaction ont été testés. Pour un meilleur rendement, plusieurs éléments considérés tels que la demande chimique en oxygène (DCO) et les matières en suspension (MES) ont été mesurées. Ce traitement a permis d’obtenir deux phases qui se séparent par décantation et flottation. Afin de déterminer les meilleures conditions de traitement, plusieurs expériences ont été effectuées, en variant l’intensité du courant et le temps de rétention. Les résultats trouvés montrent que le pH augmente avec une salinité presque constante et les rendements obtenus sont de 90.25 % pour le MES et 88.57% pour la DCOVoir les détails

Mots clés : Traitement des eaux, Eau usée, electrocoagulation, DCO, MES.

Investigation of WC decarburization effect on the microstructure and wear behavior of WC-Ni hardfacing under dry and alkaline wet conditions

B. Cheniti, D. Miroud, P. Hvizdoš, j. Balko, R. Sedlák, T. Csanádi, B. BELKESSA, M. Fides (2018)
Article de journal

The performance of drilling tools hardfacing in different conditions is strongly related to microstructural aspect of the coating and to the adhesion with the substrate. In the present investigation, the manual oxy-acetylene brazing process was employed for AISI 1020 steel hardfacing using WC-Ni. The substrate/hard facing interface was particularly studied which was a Ni-Cr-Al-Mo interlayer prepared by flame thermal spray method. The microstructural results exhibit a good embedding of WC particles into the Ni matrix, where the inter-diffusion of Ni, Cr, and Fe elements at the interface is enhanced using the interlayer. The dissolution and decarburization phenomena of WC particles with the formation of W2C eutectic phase and their effect on the decohesion and pull out of the particles during the wear test were studied. The hardness (HIT) and Young's modulus (EIT) of different parts of the hardfacing were investigated by instrumented nanoindentation. The wear resistance of the surface coatings under alkaline condition using sodium hydroxide (NaOH) basic solution of pH?=?12 is two times higher than under dry condition. Furthermore, the formation of SiO2 third body stripes along the wear track promotes the decrease of the friction coefficient and the volume loss. On the other side, the wear mechanism is adhesive with severe plastic deformation of the Ni matrix in dry condition and oxidative/abrasive wear in alkaline wet condition.Voir les détails

Mots clés : Interface, WC dissolution, Hardfacing, inter-diffusion, Decarburization

Effect of brazing current on microstructure and mechanical behavior of WC-Co/AISI 1020 steel TIG brazed joint

B. Cheniti, D.Miroud, R.Badji, D.Allou, T.Csanádi, M.Fides, P. Hvizdoš (2017)
Article de journal

In this work, the WC-Co carbide/1020 steel brazed joints which were prepared by Tungsten Inert Gas (TIG) process using different brazing currents have been studied. The peak temperature reached by increasing the brazing current caused remarkable inter-diffusion of Ni, Mn, Cu and Co elements between the braze and the base materials. The higher the brazing current was, the larger the diffusion extent of these elements became and the greater the WC rearrangement occured. As the diffusion rate of Ni towards the WC-Co was enhanced through increasing brazing current, a short range diffusion of Co element towards the braze was recorded. A Special Shear Test (SST) conducted at room temperature revealed the best bonding strength for the current of 80A. Besides, hardness (HIT) and elastic modulus (EIT) values of the interfaces were situated between those of the braze and the base materials.Voir les détails

Mots clés : WC-Co cemented carbide, TIG brazing, inter-diffusion, Interface, Nano-indentation