https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Sun, 12 Jul 2026 11:49:43 GMT 2026-07-12T11:49:43Z http://hdl.handle.net/10985/24824 Austenitic-to-austenitic-ferritic stainless steel transformation via PVD powder surface functionalization and spark plasma sintering ARDIGO-BESNARD, Maria-Rosa; BESNARD, Aurélien; PINOT, Yoann; BUSSIÈRE, Florian; CHATEAU-CORNU, J.-P.; VANDENABEELE, C.; LUCAS, S.; WATIEZ, Noé; DESCAMPS-MANDINE, Armel; JOSSE, Claudie; PROIETTI, Arnaud The present work investigates a new alloy design approach to elaborate stainless steel grades with an austeniticferritic microstructure. The originality of the study is the use, as starting material, of a 316 L austenitic powder coated by a thin chromium layer deposited by physical vapor deposition (PVD) technique. The coated powder was then consolidated by spark plasma sintering (SPS), a powder metallurgy process allowing the fast elaboration of dense materials with a fine-grained microstructure. The chromium coating, characterized by scanning and transmission electron microscopy, presents a columnar microstructure, formed by nanometric crystallites, well reproduced by the simulation of the film growth. The characterizations performed after sintering show that the initial austenitic powder particles are still visible in the bulk microstructure. On the other hand, a tetragonal σ phase enriched in chromium and molybdenum forms in the interparticular regions. After annealing treatment followed by quenching, the tetragonal phase transforms into the expected ferrite. The results prove that using a coated powder is a promising and innovative way to elaborate new steel grades with a two-phase austeniticferritic microstructure. This original approach can have the advantage of obtaining steels with a controlled microstructure and the desired amount of phases in the final bulk. Fri, 01 Mar 2024 00:00:00 GMT http://hdl.handle.net/10985/24824 2024-03-01T00:00:00Z ARDIGO-BESNARD, Maria-Rosa BESNARD, Aurélien PINOT, Yoann BUSSIÈRE, Florian CHATEAU-CORNU, J.-P. VANDENABEELE, C. LUCAS, S. WATIEZ, Noé DESCAMPS-MANDINE, Armel JOSSE, Claudie PROIETTI, Arnaud The present work investigates a new alloy design approach to elaborate stainless steel grades with an austeniticferritic microstructure. The originality of the study is the use, as starting material, of a 316 L austenitic powder coated by a thin chromium layer deposited by physical vapor deposition (PVD) technique. The coated powder was then consolidated by spark plasma sintering (SPS), a powder metallurgy process allowing the fast elaboration of dense materials with a fine-grained microstructure. The chromium coating, characterized by scanning and transmission electron microscopy, presents a columnar microstructure, formed by nanometric crystallites, well reproduced by the simulation of the film growth. The characterizations performed after sintering show that the initial austenitic powder particles are still visible in the bulk microstructure. On the other hand, a tetragonal σ phase enriched in chromium and molybdenum forms in the interparticular regions. After annealing treatment followed by quenching, the tetragonal phase transforms into the expected ferrite. The results prove that using a coated powder is a promising and innovative way to elaborate new steel grades with a two-phase austeniticferritic microstructure. This original approach can have the advantage of obtaining steels with a controlled microstructure and the desired amount of phases in the final bulk. http://hdl.handle.net/10985/23012 Effect of Pre-Oxidation on a Ti PVD Coated Ferritic Steel Substrate during High-Temperature Aging ARDIGO-BESNARD, Maria-Rosa; BESNARD, Aurélien; NKOU BOUALA, Galy; BOULET, Pascal; PINOT, Yoann; OSTORERO, Quentin A PVD coating is often applied on the surface of metallic alloys to improve their high-temperature resistance. In the present work, a thin titanium layer (1.2 µm) was deposited by PVD on the surface of a stainless steel substrate before high-temperature exposure (800 °C in ambient air). The underlying idea is that metallic Ti converts into Ti oxide (TiO2) during high-temperature aging at 800 °C, thereby slowing down the substrate oxidation. The stability of the coating with and without substrate pre-oxidation was investigated. Morphological, structural, and chemical characterizations were performed and completed by simulation of the film growth and measurement of the mechanical state of the film and the substrate. In the case of the sample that was not pre-oxidized, the oxidation of the steel was slowed down by the TiO2 scale but spallation was observed. On the other hand, when the steel was pre-oxidized, TiO2 provided more significant protection against high-temperature oxidation, and spalling or cracking did not occur. A combination of different kinds of stress could explain the two different behaviors, namely, the mechanical state of the film and the substrate before oxidation, the growing stress, and the thermal stress occurring during cooling down. Thu, 01 Dec 2022 00:00:00 GMT http://hdl.handle.net/10985/23012 2022-12-01T00:00:00Z ARDIGO-BESNARD, Maria-Rosa BESNARD, Aurélien NKOU BOUALA, Galy BOULET, Pascal PINOT, Yoann OSTORERO, Quentin A PVD coating is often applied on the surface of metallic alloys to improve their high-temperature resistance. In the present work, a thin titanium layer (1.2 µm) was deposited by PVD on the surface of a stainless steel substrate before high-temperature exposure (800 °C in ambient air). The underlying idea is that metallic Ti converts into Ti oxide (TiO2) during high-temperature aging at 800 °C, thereby slowing down the substrate oxidation. The stability of the coating with and without substrate pre-oxidation was investigated. Morphological, structural, and chemical characterizations were performed and completed by simulation of the film growth and measurement of the mechanical state of the film and the substrate. In the case of the sample that was not pre-oxidized, the oxidation of the steel was slowed down by the TiO2 scale but spallation was observed. On the other hand, when the steel was pre-oxidized, TiO2 provided more significant protection against high-temperature oxidation, and spalling or cracking did not occur. A combination of different kinds of stress could explain the two different behaviors, namely, the mechanical state of the film and the substrate before oxidation, the growing stress, and the thermal stress occurring during cooling down. http://hdl.handle.net/10985/27106 Physico-Chemical and Mechanical Properties of DC-Sputtered ZrO2 Coatings Prepared by Oblique Angle Deposition GZAIEL, Asma; AOUADI, Khalil; BESNARD, Aurélien; NOUVEAU, Corinne; PINOT, Yoann; BOUCHOUCHA, Faker; BOUAOUINA, Boudjemaa In this study, a ZrO2 thin film was deposited onto a Ti6Al4V substrate using the Oblique Angle Deposition (OAD) technique. The influence of the substrate/Zr target an-gle (15°, 30°, 45°, and 60°) was investigated, with a fixed azimuthal orientation (Phi) of 180°. The primary objective of this work is to develop and characterize novel biocompatible coat-ings for hip prosthesis implants with a complex 3D spherical geometry. The OAD method enables thin film deposition on such geometries and enhances understanding of how the par-ticle incidence angle affects the surface morphology and microstructure of zirconium oxide (ZrO2) thin films. This study combines an experimental approach DC magnetron sputtering with a multi-scale numerical approach using Monte Carlo codes (SRIM, SIMTRA, and NASCAM). The structure, texture, and growth of the ZrO2 coatings were analyzed via X-ray diffraction (XRD), while microstructure and surface morphology were examined using scan-ning electron microscopy (SEM). Hardness and Young’s modulus were determined through nanoindentation testing. Results indicate that increasing the oblique angle leads to a decrease in hardness. Experimental and numerical findings complement each other, offering deeper insight into the deposition phenomena. SIMTRA simulations closely replicate experimental observations: a higher number of incident particles results in increased coating thickness. Additionally, the film thickness decreases with increasing substrate inclination angle. The microstructure of ZrO₂ thin films is strongly influenced by substrate orientation, and coated substrates demonstrate superior performance compared to their uncoated counterparts. Sat, 25 Oct 2025 00:00:00 GMT http://hdl.handle.net/10985/27106 2025-10-25T00:00:00Z GZAIEL, Asma AOUADI, Khalil BESNARD, Aurélien NOUVEAU, Corinne PINOT, Yoann BOUCHOUCHA, Faker BOUAOUINA, Boudjemaa In this study, a ZrO2 thin film was deposited onto a Ti6Al4V substrate using the Oblique Angle Deposition (OAD) technique. The influence of the substrate/Zr target an-gle (15°, 30°, 45°, and 60°) was investigated, with a fixed azimuthal orientation (Phi) of 180°. The primary objective of this work is to develop and characterize novel biocompatible coat-ings for hip prosthesis implants with a complex 3D spherical geometry. The OAD method enables thin film deposition on such geometries and enhances understanding of how the par-ticle incidence angle affects the surface morphology and microstructure of zirconium oxide (ZrO2) thin films. This study combines an experimental approach DC magnetron sputtering with a multi-scale numerical approach using Monte Carlo codes (SRIM, SIMTRA, and NASCAM). The structure, texture, and growth of the ZrO2 coatings were analyzed via X-ray diffraction (XRD), while microstructure and surface morphology were examined using scan-ning electron microscopy (SEM). Hardness and Young’s modulus were determined through nanoindentation testing. Results indicate that increasing the oblique angle leads to a decrease in hardness. Experimental and numerical findings complement each other, offering deeper insight into the deposition phenomena. SIMTRA simulations closely replicate experimental observations: a higher number of incident particles results in increased coating thickness. Additionally, the film thickness decreases with increasing substrate inclination angle. The microstructure of ZrO₂ thin films is strongly influenced by substrate orientation, and coated substrates demonstrate superior performance compared to their uncoated counterparts. http://hdl.handle.net/10985/25402 316L Stainless-Steel Carburizing Close to Eutectic Transformation Using the Spark Plasma Sintering Process PINOT, Yoann; BESNARD, Aurélien; ARDIGO-BESNARD, Maria-Rosa; BUSSIÈRE, Florian This work focuses on the 316L austenitic stainless-steel case-hardening microstructure, after the SPS process near the solid/liquid state transition temperature. This process, faster than conventional carburizing techniques, is equivalent to weld cladding, allowing the achievement of high surface carbon contents with large-size carbide grains in the case of partial melting. Three distinct zones were formed: internal carburizing, carburizing with melting, and carburizing with melting and chromium depletion; all three composed of mixed carbides (Cr0.4Fe0.6)7C3 distributed in an austenitic matrix. The internal carburizing layer growths following a parabolic kinetic law with kp 1027 cm2/s, while the advancement of the melting front is very fast and follows a linear law with kl = 1.0 3 1024 cm2/s at 1100 °C. The Cr-depleted fusion zone microstructure is similar to a composite material with a metallic matrix, which includes graphite particles, Mo-rich intermetallic phases, and core-shell eutectic carbides. The partial melting zone without Cr depletion shows the formation of a dense carbide layer with diameters exceeding 10 µm, constituting 60% of the volume, and achieving a hardness of 850 HV5. Its wear rate is about 100 times lower than the 316L steel, indicating a significant improvement in the alloy's wear behavior. Tue, 26 Mar 2024 00:00:00 GMT http://hdl.handle.net/10985/25402 2024-03-26T00:00:00Z PINOT, Yoann BESNARD, Aurélien ARDIGO-BESNARD, Maria-Rosa BUSSIÈRE, Florian This work focuses on the 316L austenitic stainless-steel case-hardening microstructure, after the SPS process near the solid/liquid state transition temperature. This process, faster than conventional carburizing techniques, is equivalent to weld cladding, allowing the achievement of high surface carbon contents with large-size carbide grains in the case of partial melting. Three distinct zones were formed: internal carburizing, carburizing with melting, and carburizing with melting and chromium depletion; all three composed of mixed carbides (Cr0.4Fe0.6)7C3 distributed in an austenitic matrix. The internal carburizing layer growths following a parabolic kinetic law with kp 1027 cm2/s, while the advancement of the melting front is very fast and follows a linear law with kl = 1.0 3 1024 cm2/s at 1100 °C. The Cr-depleted fusion zone microstructure is similar to a composite material with a metallic matrix, which includes graphite particles, Mo-rich intermetallic phases, and core-shell eutectic carbides. The partial melting zone without Cr depletion shows the formation of a dense carbide layer with diameters exceeding 10 µm, constituting 60% of the volume, and achieving a hardness of 850 HV5. Its wear rate is about 100 times lower than the 316L steel, indicating a significant improvement in the alloy's wear behavior.