https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Fri, 17 Apr 2026 11:54:58 GMT 2026-04-17T11:54:58Z http://hdl.handle.net/10985/10881 Influence d’une eau fortement salée sur la propagation de fissure par fatigue de l’acier inoxydable 17 - 4 PH. SMATI, Mohamed; NASRI, Mustapha; MARHABI, Driss; IOST, Alain Cette étude est inspirée d’un retour d’expérience des pompes d’injection d’eau de mer et de brut de pétrole pour les opérations d’une plateforme de production pétrolière. Dans ces machines tournantes, la fatigue et la corrosion sont les causes essentielles de détérioration des pièces mécaniques. Le souci permanent consiste à empêcher la dégradation des tiges des pistons des pompes soumises à un environnement agressif. En effet, lors de l’exposition de ce type d’acier à l’eau de Process (eau de gisement), nous observons que la corrosion affecte l'intégrité du matériau en favorisant l'amorçage de fissures et/ou en provoquant des attaques localisées. Le principal objectif du travail réalisé est d’améliorer la compréhension des mécanismes qui régissent le phénomène de fatigue-corrosion. Les essais ont été effectués à température ambiante sur une nuance de l’acier inoxydable 17-4 PH dans les trois conditions suivantes : matériau de base, matériau corrodé et matériau nitruré. Les essais de propagation ont été réalisés sur une machine hydraulique de type INSTRON 8516. Pour caractériser la propagation dans le cas où la fissure de fatigue se propage à l’air depuis un ensemble de piqûres de corrosion, une série d’essais sont réalisés sur des éprouvettes CT ayant subi une fragilisation par l’eau de procédé à température ambiante. Le but est de comprendre l’influence de la corrosion et comparer les vitesses de propagations des fissures d’éprouvettes corrodées à celles du matériau de base. Un premier constat sur la rupture de pièces de machines en contact avec l’eau de mer est dû à la propagation en ambiance corrosive de fissures par fragilisation inter-granulaire et par conséquent un vieillissement prématuré pendant le fonctionnement de surcharge cyclique. Pour améliorer les effets d’avarie en milieu corrosif, nous proposons le traitement surfacique par nitruration gazeuse à 540 °C de l’acier inoxydable 17-4 PH. Ceci a pour but de comparer les vitesses de propagations de fissures dans l’éprouvette nitrurée aux précédentes.; This study was inspired by the injection pumps sea water for the operation of an oil production platform. In these rotating machines, fatigue is a major cause of deterioration of mechanical parts. Once a crack is present in a material, it will tend to grow under the influence of cyclic loading. The crack may be initiated by fatigue or may be caused by an impact, or similar event. Once the crack is released, it will grow to a critical length and product the fracture of the concerned component. The present paper is aimed at investigating both the effect of produced water (water coming from crude oil well) and the effect of nitriding on the fatigue crack growth behavior in ambient environment for a 17-4PH grade stainless steel. We want also to understand the mechanisms of the fatigue crack propagation under different conditions. With the fatigue test, a quantitative microscopic analysis of the fracture surfaces is carried out to observe and identify the micro effects of the fatigue process. The fatigue crack growth rate in the corroded material is higher than the base material and lower in nitriding material than the base material. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10985/10881 2011-01-01T00:00:00Z SMATI, Mohamed NASRI, Mustapha MARHABI, Driss IOST, Alain Cette étude est inspirée d’un retour d’expérience des pompes d’injection d’eau de mer et de brut de pétrole pour les opérations d’une plateforme de production pétrolière. Dans ces machines tournantes, la fatigue et la corrosion sont les causes essentielles de détérioration des pièces mécaniques. Le souci permanent consiste à empêcher la dégradation des tiges des pistons des pompes soumises à un environnement agressif. En effet, lors de l’exposition de ce type d’acier à l’eau de Process (eau de gisement), nous observons que la corrosion affecte l'intégrité du matériau en favorisant l'amorçage de fissures et/ou en provoquant des attaques localisées. Le principal objectif du travail réalisé est d’améliorer la compréhension des mécanismes qui régissent le phénomène de fatigue-corrosion. Les essais ont été effectués à température ambiante sur une nuance de l’acier inoxydable 17-4 PH dans les trois conditions suivantes : matériau de base, matériau corrodé et matériau nitruré. Les essais de propagation ont été réalisés sur une machine hydraulique de type INSTRON 8516. Pour caractériser la propagation dans le cas où la fissure de fatigue se propage à l’air depuis un ensemble de piqûres de corrosion, une série d’essais sont réalisés sur des éprouvettes CT ayant subi une fragilisation par l’eau de procédé à température ambiante. Le but est de comprendre l’influence de la corrosion et comparer les vitesses de propagations des fissures d’éprouvettes corrodées à celles du matériau de base. Un premier constat sur la rupture de pièces de machines en contact avec l’eau de mer est dû à la propagation en ambiance corrosive de fissures par fragilisation inter-granulaire et par conséquent un vieillissement prématuré pendant le fonctionnement de surcharge cyclique. Pour améliorer les effets d’avarie en milieu corrosif, nous proposons le traitement surfacique par nitruration gazeuse à 540 °C de l’acier inoxydable 17-4 PH. Ceci a pour but de comparer les vitesses de propagations de fissures dans l’éprouvette nitrurée aux précédentes. This study was inspired by the injection pumps sea water for the operation of an oil production platform. In these rotating machines, fatigue is a major cause of deterioration of mechanical parts. Once a crack is present in a material, it will tend to grow under the influence of cyclic loading. The crack may be initiated by fatigue or may be caused by an impact, or similar event. Once the crack is released, it will grow to a critical length and product the fracture of the concerned component. The present paper is aimed at investigating both the effect of produced water (water coming from crude oil well) and the effect of nitriding on the fatigue crack growth behavior in ambient environment for a 17-4PH grade stainless steel. We want also to understand the mechanisms of the fatigue crack propagation under different conditions. With the fatigue test, a quantitative microscopic analysis of the fracture surfaces is carried out to observe and identify the micro effects of the fatigue process. The fatigue crack growth rate in the corroded material is higher than the base material and lower in nitriding material than the base material. http://hdl.handle.net/10985/8356 Effect of layer thickness on thermal properties of multilayer thin films produced by PVD TLILI, Brahim; WALOCK, Michael J.; NASRI, Mustapha; GHRIB, Taher; NOUVEAU, Corinne Cr/CrN/CrAlN, CrN/CrAlN and Cr/CrN thin layers were deposited by PVD (Physical Vapor Deposition). The multilayers were obtained from the combined deposition of different layers Cr, CrN and CrAlN thick films on on AISI4140 steel and silicon substrates at 200 °C, and evaluated with respect to fundamental properties such as structure and thermal properties. Cr, CrN and CrAlN single layers were also prepared for comparison purposes. The structural and morphological properties of PVD layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with EDS + WDS microanalyses, stresses were determined by the Newton’s rings methods using the Stoney’s equation and surface hardening and hardness profiles were evaluated by micro hardness measurements. The XRD data and HRTEM showed that both the Cr/CrN, CrN/CrAlN and Cr/CrN/CrAlN multilayer coatings exhibited B1NaCl structure with a prominent reflection along (200) plane, and CrAlN sub-layer microstructures composed of nanocrystallites uniformly embedded in an amorphous matrix. The innovation of this work was to use the thickness of three different coating types to determine the thermal properties. Furthermore, an empirical equation was developed for the thermal properties variations with temperature of AISI4140 steel coated with different multilayer coatings. The thermal conductivity of CrAlN single layered was lower than the multilayer and the bulk material AISI4140. Moreover, the influences of structure and composition of the multilayer coatings on the thermal properties are discussed. The thermal conductivity of nanoscale thin film is remarkably lower than that of bulk materials because of its various size effects. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10985/8356 2012-01-01T00:00:00Z TLILI, Brahim WALOCK, Michael J. NASRI, Mustapha GHRIB, Taher NOUVEAU, Corinne Cr/CrN/CrAlN, CrN/CrAlN and Cr/CrN thin layers were deposited by PVD (Physical Vapor Deposition). The multilayers were obtained from the combined deposition of different layers Cr, CrN and CrAlN thick films on on AISI4140 steel and silicon substrates at 200 °C, and evaluated with respect to fundamental properties such as structure and thermal properties. Cr, CrN and CrAlN single layers were also prepared for comparison purposes. The structural and morphological properties of PVD layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with EDS + WDS microanalyses, stresses were determined by the Newton’s rings methods using the Stoney’s equation and surface hardening and hardness profiles were evaluated by micro hardness measurements. The XRD data and HRTEM showed that both the Cr/CrN, CrN/CrAlN and Cr/CrN/CrAlN multilayer coatings exhibited B1NaCl structure with a prominent reflection along (200) plane, and CrAlN sub-layer microstructures composed of nanocrystallites uniformly embedded in an amorphous matrix. The innovation of this work was to use the thickness of three different coating types to determine the thermal properties. Furthermore, an empirical equation was developed for the thermal properties variations with temperature of AISI4140 steel coated with different multilayer coatings. The thermal conductivity of CrAlN single layered was lower than the multilayer and the bulk material AISI4140. Moreover, the influences of structure and composition of the multilayer coatings on the thermal properties are discussed. The thermal conductivity of nanoscale thin film is remarkably lower than that of bulk materials because of its various size effects. http://hdl.handle.net/10985/12000 Experimental study of a six new ball-burnishing strategies effects on the Al-alloy flat surfaces integrity enhancement AMDOUNI, Hatem; BOUZAIENE, Hassen; VAN GORP, Adrien; NASRI, Mustapha; IOST, Alain; COOREVITS, Thierry; MONTAGNE, Alex Abstract: In the literature, the most studies conducted on the flat surface ball-burnishing process have been focused on the most important classical factors like burnishing speed, lateral feed, and the ball-burnishing load or pressure on the treated surfaces integrity enhancement. In this research, ballburnishing strategies are studied as a new ball-burnishing factor. The aim of this research is to show the improvement of the flat surface integrity of 2017A-T451 aluminum alloy using six new ball-burnishing strategies. Ball-burnishing tests were conducted in two passes using the recommended values of the ball-burnishing factors (the penetration depth ab is 40 μm, the linear ball-burnishing speed Vb is 500 mm/min and a lateral feed f of 0.2 mm). Two ball-burnishing strategies in two successive and perpendicular passes to the machining direction and four ball-burnishing strategies in two crossed passes have been designed and tested to improve the flat surfaces integrity of the samples. The characterization and the micrographic observations of the ball-burnished surfaces show that using the best ball-burnishing strategy leads to a great enhancement in surface quality. The latter is predicted by a gain in average roughness Ra of 81 %, an improvement in the mean spacing of profile irregularities Sm of 34 %, an enhancement in surface Nano-hardness HIT of 17 %, and sub-layer hardness betterment up to a depth of 500 μm. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/12000 2017-01-01T00:00:00Z AMDOUNI, Hatem BOUZAIENE, Hassen VAN GORP, Adrien NASRI, Mustapha IOST, Alain COOREVITS, Thierry MONTAGNE, Alex Abstract: In the literature, the most studies conducted on the flat surface ball-burnishing process have been focused on the most important classical factors like burnishing speed, lateral feed, and the ball-burnishing load or pressure on the treated surfaces integrity enhancement. In this research, ballburnishing strategies are studied as a new ball-burnishing factor. The aim of this research is to show the improvement of the flat surface integrity of 2017A-T451 aluminum alloy using six new ball-burnishing strategies. Ball-burnishing tests were conducted in two passes using the recommended values of the ball-burnishing factors (the penetration depth ab is 40 μm, the linear ball-burnishing speed Vb is 500 mm/min and a lateral feed f of 0.2 mm). Two ball-burnishing strategies in two successive and perpendicular passes to the machining direction and four ball-burnishing strategies in two crossed passes have been designed and tested to improve the flat surfaces integrity of the samples. The characterization and the micrographic observations of the ball-burnished surfaces show that using the best ball-burnishing strategy leads to a great enhancement in surface quality. The latter is predicted by a gain in average roughness Ra of 81 %, an improvement in the mean spacing of profile irregularities Sm of 34 %, an enhancement in surface Nano-hardness HIT of 17 %, and sub-layer hardness betterment up to a depth of 500 μm. http://hdl.handle.net/10985/10776 Modeling and optimization of a ball-burnished aluminum alloy flat surface with a crossed strategy based on response surface methodology HAMDOUNI, Hatem; BOUZAIENE, Hassen; NASRI, Mustapha; IOST, Alain; MONTAGNE, Alex In this work, a new ball-burnishing strategy, in two crossed passes, was applied on the flat machined surface of 2017A-T451 aluminum alloy to investigate the influence of three classical ball-burnishing factors (burnishing speed Vb in mm/min, depth of penetration ab in μm and lateral feed f in mm) on the treated surface integrity enhancement. Experimental work is based on the application of an experimental face-centered composite design (CCD) formed by three factors at three levels. The mathematical modeling of the average roughness Ra, of the mean spacing of roughness profile irregularities Sm and of the surface hardness HIT of the treated surfaces was performed by the response surface methodology (RSM). Best ball-burnished surface integrity has been established by the application of optimal ballburnishing studied factors (Vb = 500 mm/min, ab=40 μm, and f = 0.2 mm). High surface quality is then characterized by a gain in average roughness Ra of 81 %, an enhancement in the mean spacing of profile irregularities Sm of 34%and an improvement in surface nano-hardness HIT of 17 % when compared to the machined surface. Machined and ballburnished optimized surface characterization confirms surface finishing process power and contribution to surface integrity enhancement of treated flat surface. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/10776 2016-01-01T00:00:00Z HAMDOUNI, Hatem BOUZAIENE, Hassen NASRI, Mustapha IOST, Alain MONTAGNE, Alex In this work, a new ball-burnishing strategy, in two crossed passes, was applied on the flat machined surface of 2017A-T451 aluminum alloy to investigate the influence of three classical ball-burnishing factors (burnishing speed Vb in mm/min, depth of penetration ab in μm and lateral feed f in mm) on the treated surface integrity enhancement. Experimental work is based on the application of an experimental face-centered composite design (CCD) formed by three factors at three levels. The mathematical modeling of the average roughness Ra, of the mean spacing of roughness profile irregularities Sm and of the surface hardness HIT of the treated surfaces was performed by the response surface methodology (RSM). Best ball-burnished surface integrity has been established by the application of optimal ballburnishing studied factors (Vb = 500 mm/min, ab=40 μm, and f = 0.2 mm). High surface quality is then characterized by a gain in average roughness Ra of 81 %, an enhancement in the mean spacing of profile irregularities Sm of 34%and an improvement in surface nano-hardness HIT of 17 % when compared to the machined surface. Machined and ballburnished optimized surface characterization confirms surface finishing process power and contribution to surface integrity enhancement of treated flat surface. http://hdl.handle.net/10985/7990 Fretting wear performances of multilayered PVD TiAlZrN/TiAlN/TiAl on AISI 4140 steel TLILI, Brahim; NASRI, Mustapha; AYARI, F.; NOUVEAU, Corinne Nowadays, most surface treatments are realized through vapor deposition techniques as thin hard coatings to guarantee; high surface hardness, low friction coefficient and improve wear resistance. Several experimental investigations have let to the development of a (TiAlCN/TiAlN/TiAl) and (TiAlZrN/TiAlN/TiAl) coatings in preference to the traditional TiN coating. In the current paper research conducted on fretting wear of a (TiAlCN/TiAlN/TiAl) and a (TiAlZrN/TiAlN/TiAl) multilayer coatings deposited by reactive DC (magnetron sputtering) of Ti-Al and Ti-Al-Zr alloys on AISI4140 steel. Fretting wear tests (20.000 cycles at 5 Hz) were conducted in ambient conditions, where the interaction between normal load and displacement amplitude determines the fretting regime. The influence of the normal load and displacement amplitude on the coefficients of instantaneous coefficient of friction and stabilized coefficient of friction is different from the two multilayer coated steels. The PVD coating (TiAlZrN/TiAlN/TiAl) reduces the friction. The worn volume of coated AISI4140 steel is sensitive to normal load and displacement amplitude. The relation between worn volume and cumulative dissipated energy was established for the two coated steels. The energetic fretting wear coefficients were also determined. A multilayer (TiAlZrN/TiAlN/TiAl) coating has a low energetic wear coefficient. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/10985/7990 2008-01-01T00:00:00Z TLILI, Brahim NASRI, Mustapha AYARI, F. NOUVEAU, Corinne Nowadays, most surface treatments are realized through vapor deposition techniques as thin hard coatings to guarantee; high surface hardness, low friction coefficient and improve wear resistance. Several experimental investigations have let to the development of a (TiAlCN/TiAlN/TiAl) and (TiAlZrN/TiAlN/TiAl) coatings in preference to the traditional TiN coating. In the current paper research conducted on fretting wear of a (TiAlCN/TiAlN/TiAl) and a (TiAlZrN/TiAlN/TiAl) multilayer coatings deposited by reactive DC (magnetron sputtering) of Ti-Al and Ti-Al-Zr alloys on AISI4140 steel. Fretting wear tests (20.000 cycles at 5 Hz) were conducted in ambient conditions, where the interaction between normal load and displacement amplitude determines the fretting regime. The influence of the normal load and displacement amplitude on the coefficients of instantaneous coefficient of friction and stabilized coefficient of friction is different from the two multilayer coated steels. The PVD coating (TiAlZrN/TiAlN/TiAl) reduces the friction. The worn volume of coated AISI4140 steel is sensitive to normal load and displacement amplitude. The relation between worn volume and cumulative dissipated energy was established for the two coated steels. The energetic fretting wear coefficients were also determined. A multilayer (TiAlZrN/TiAlN/TiAl) coating has a low energetic wear coefficient. http://hdl.handle.net/10985/10791 Modélisation du comportement élastoplastique d’un revêtement Fe-Zn par nanoindentation : Approche inverse basée sur les plans d’expériences et les algorithmes génétiques multiobjectifs NASSER, Mohamed; CHAMEKH, Abdessalem; GUILLEMOT, Gildas; NASRI, Mustapha; IOST, Alain La prise en compte du comportement du revêtement des tôles galvanisées détermine leur intégration microstructurale et tribologique au substrat lors de la mise en forme en grande déformation. Ce travail porte sur l’identification des paramètres d’un modèle élastoplastique du comportement d’un revêtement Fe-Zn déposé sur un substrat en acier Dual-Phase DP600. La mesure de la dureté et du module d’Young en mode continue CSM (Continuouss Stiffness Measurement) de nanoindentation assure le choix adéquat des niveaux de facteurs et des contraintes multiobjectifs garantissant l’unicité de la solution optimisée. La validation de cette approche inverse est établie via une simulation EF couplée à une évaluation statistique pour lequel l’écart Simulation/Expérience est valorisé par une erreur inférieure à 2%.; Taking into account the behavior of coating the galvanized sheets; determines their microstructural and tribological integration with the substrate at the time of working in great deformation. This work concerns the parameters identification of an elastoplastic model of the behavior of a coating Fe-Zn deposited on a substrate in steel Dual-Phase DP600. The measurement of the hardness and the Young modulus in mode CSM (Continuouss Stiffness Measurement) of nanoindentation ensures the adequate choice of the levels of factors and the multiobjectives constraints guaranteeing a unique and optimized solution. The validation of this reverse approach is established via a simulation EF coupled to a statistic evaluation for which the Simulation/Experience variation is valorized by an error lower than 2%. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/10791 2015-01-01T00:00:00Z NASSER, Mohamed CHAMEKH, Abdessalem GUILLEMOT, Gildas NASRI, Mustapha IOST, Alain La prise en compte du comportement du revêtement des tôles galvanisées détermine leur intégration microstructurale et tribologique au substrat lors de la mise en forme en grande déformation. Ce travail porte sur l’identification des paramètres d’un modèle élastoplastique du comportement d’un revêtement Fe-Zn déposé sur un substrat en acier Dual-Phase DP600. La mesure de la dureté et du module d’Young en mode continue CSM (Continuouss Stiffness Measurement) de nanoindentation assure le choix adéquat des niveaux de facteurs et des contraintes multiobjectifs garantissant l’unicité de la solution optimisée. La validation de cette approche inverse est établie via une simulation EF couplée à une évaluation statistique pour lequel l’écart Simulation/Expérience est valorisé par une erreur inférieure à 2%. Taking into account the behavior of coating the galvanized sheets; determines their microstructural and tribological integration with the substrate at the time of working in great deformation. This work concerns the parameters identification of an elastoplastic model of the behavior of a coating Fe-Zn deposited on a substrate in steel Dual-Phase DP600. The measurement of the hardness and the Young modulus in mode CSM (Continuouss Stiffness Measurement) of nanoindentation ensures the adequate choice of the levels of factors and the multiobjectives constraints guaranteeing a unique and optimized solution. The validation of this reverse approach is established via a simulation EF coupled to a statistic evaluation for which the Simulation/Experience variation is valorized by an error lower than 2%.