The interaction of water molecules on a nickel surface was studied using ReaxFF (reactive force f... more The interaction of water molecules on a nickel surface was studied using ReaxFF (reactive force field) molecular dynamics.This approach was originally developed by van Duinet al.to study the hydrocarbon chemistry and the catalytic properties of organic compounds. To our knowledge, this method has not been used to study the corrosion processes of nickel exposed to water, which is what we set out to achieve in the present investigation. To do so, calculations were first performed using ReaxFF in order to reproduce certain well-known properties of pure nickel and nickel-water systems. This allowed us to study the adsorption of a single water molecule interacting with an optimized nickel surface. We also investigated the interaction of 405 molecules of water (ρ=0.99 g.cm-3) on the (100), (110) and (111) surfaces of a single crystal of nickel at 300 K. The results show that a water bilayer is adsorbed on nickel surfaces: the first water layer is directly bonded to the surface, whereas th...
We investigated the oxidation of nanocrystalline aluminum surfaces by using variable charge molec... more We investigated the oxidation of nanocrystalline aluminum surfaces by using variable charge molecular dynamics at 600 K under three oxygen pressures: 1, 10 and 20 atm. The interaction potential was described by the electrostatic plus (Es+) model that allows dynamical charge transfer among atoms. We mainly focused on the effect of the oxygen pressure on the oxidation kinetic, the chemical composition and the microstructure of the oxide films formed. The results show that oxidation kinetics as well as chemical composition and microstructure depend on the applied oxygen pressure. The oxide film thickness tends to a limiting value equal to ~3 nm. Finally, we obtained a partially crystalline oxide films for all oxygen pressures and we observed that the degree of crystallinity increases with time.
Stabilized austenitic stainless steels are widely used in nuclear and oil industries. The 316 Nb ... more Stabilized austenitic stainless steels are widely used in nuclear and oil industries. The 316 Nb steel grade presented in this study holds a small amount of delta ferrite in the austenitic matrix which tends to transform into sigma phase during prolonged exposures in the temperature range of 600-1000°C. Sigma phase is promoted by ferritic elements such as chromium, molybdenum, niobium and silicon. Time-Temperature-Transformation (TTT) diagram of the δ-ferrite evolution is established thanks to DSC experiments and quantitative metallographic analysis. It is observed that the highest sigma phase formation rate occurs between 800 and 900°C, and that the transformation of ferrite begins after a few minutes of exposure in this temperature range. The microstructure of transformed δ-ferrite is mostly dominated by the eutectoid mixture σ + γ2. Tensile tests were performed for three different cooling conditions: a significant embrittlement attributed to the δ-ferrite transformation is measur...
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
We investigate the oxidation of nanocrystalline aluminum surfaces using molecular dynamics (MD) s... more We investigate the oxidation of nanocrystalline aluminum surfaces using molecular dynamics (MD) simulations with the variable charge model that allows charge dynamically transfer among atoms. The interaction potential between atoms is described by the electrostatic plus (Es+) potential model, which is composed of an embedded atom method potential and an electrostatic term. The simulations were performed from 300 to 750K on polycrystalline samples with a mean grain size of 5 nanometers. We mainly focused on the effect of the temperature parameter on the oxidation kinetic. The results show that, beyond a first linear regime, the kinetics follow a direct logarithmic law (governed by diffusion process) and tend to a limiting value corresponding to a thickness of ~3nm. We also characterized at 600K the effects of an external applied strain on the microstructure and the chemical composition of the oxide films formed at the surface. In particular, we obtained a partially crystalline oxide films for all temperature and we noticed a strong correlation between the degree of crystallinity of the oxide film and the oxidation temperature.
In the present paper, grid points coupled with an image analysis method are used to map strain gr... more In the present paper, grid points coupled with an image analysis method are used to map strain gradients within grains and across interfaces of duplex stainless steels at the micro-and nanoscale under straining conditions (4.5% plastic strain). Highly heterogeneous strain field are obtained and sites where high strain gradients exist are identified. Local electrochemical measurements are then performed in NaCl-based media within these sites by means of the electrochemical microcell technique and 20 µm microcapillaries in order to propose new mechanical-electrochemical criteria leading to a significant enhancement of anodic and/or cathodic reactions and pitting susceptibility of deformed materials.
The influence of residual surface stresses generated by polishing on the pitting susceptibility o... more The influence of residual surface stresses generated by polishing on the pitting susceptibility of duplex stainless steels was studied by combining microelectrochemical measurements with thermal-mechanical simulation. It has been shown that the surface stress state was the driving force for pit initiation along the austenite/ferrite interface. The local stress gradient was the key-parameter in pit initiation and the local average stress was the parameter governing the transition from metastable to stable pitting.
The aim of this work is to develop a numerical model capable of predicting the grain density in t... more The aim of this work is to develop a numerical model capable of predicting the grain density in the Mg-based matrix phase of an AZ91/SiC composite, as a function of the total mass fraction of the embedded SiC particles. Based on earlier work in a range of alloy systems, we assume an exponential relationship between the grain density and the maximum supercooling during solidification. Analysis of data from cast samples with different thicknesses, and mass fractions of added SiCp, permits conclusions to be drawn on the role of SiCp in increasing grain density. By fitting the data, an empirical nucleation law is derived that can be used in a micro model. Numerical simulation based on the model can predict the grain density of magnesium alloys containing SiC particles, using the mass fraction of the particles as inputs. These predictions are compared with measured data.
This paper describes a model developed to simulate the evolution of carbide layers (TaC/Ta 2 C) f... more This paper describes a model developed to simulate the evolution of carbide layers (TaC/Ta 2 C) formed during carburizing and annealing treatments of tantalum. The model is based on a parabolic evolution of the layer thickness during the growth, and on the carbon conservation during the annealing. In order to validate this model a MATLAB® program was developed. It enables the prediction of the evolution of the tantalum carbide layers (nature and thickness) for a desired treatment defined by a temperature, a carburizing and an annealing duration.
The influence of cutting conditions of a low carbon martensitic stainless steel (15.5wt.% Cr, 4.8... more The influence of cutting conditions of a low carbon martensitic stainless steel (15.5wt.% Cr, 4.8% Ni, 1% Mo, 0.9% Mn, 0.24% Si, 0.1% Cu, < 0.06% C and 77.46% Fe) on the microstructure is first studied using electron backscatter diffraction and transmission electron microscopy. The mechanical and corrosion behaviours of this stainless steel are then investigated. It was found that the microstructure is significantly affected near the machined surface. The formation of grain sub-boundaries or a refinement of the microstructure is observed depending on cutting conditions. Both lead to an increase of the hardness. In addition, the microstructure refinement yields to a huge increase of the average pit surface area. By contrast the average pit density is not affected by machining conditions.
Tribological behavior at both tool/chip and tool/work material interfaces should be highly consid... more Tribological behavior at both tool/chip and tool/work material interfaces should be highly considered while simulating the machining process. In fact, it is no longer accurate to suppose one independent constant friction coefficient at the tool/chip interface, since in reality it depends on the applied contact conditions, including the sliding velocity and pressure. The contact conditions at both above mentioned interfaces may affect the thermal and mechanical phenomena and consequently the surface integrity predictions. In this article, the influence of contact conditions (sliding velocity) on the tribological behavior of uncoated tungsten carbide tool against OFHC copper work material was investigated. Series of tribology tests combined with numerical simulations of the contact process were performed under different sliding speeds and contact pressures, in order to identify the friction coefficient and the heat partition between OFHC copper and tungsten carbide. The friction coefficient in function of the sliding velocity was then integrated into a FE model of the orthogonal cutting of OFHC copper and applied to surface integrity prediction.
Due to the rising interest in predicting machined surface integrity and sustainability, various m... more Due to the rising interest in predicting machined surface integrity and sustainability, various models for metal cutting simulation have been developed. However, their accuracy depends deeply on the physical description of the machining process. This study aims to develop an orthogonal cutting model for surface integrity prediction, which includes a physical-based constitutive model of Oxygen Free High Conductivity (OFHC) copper. This constitutive model incorporates the effects of the state of stress and microstructure on the work material behavior, as well as a dislocation density-based model for surface integrity prediction. The coefficients of the constitutive model were identified through a hybrid experimental/numerical approach, consisting in mechanical tests, numerical simulations and an optimization-based algorithm. The orthogonal cutting model was simulated by FEM, using ALE formulation, and was validated by comparing predicted and measured results, including residual stresses, dislocation density and grain size. The model is then used to analyze the influence of the cutting parameters and cutting geometry on surface integrity, and its results are compared to those obtained by the Johnson-Cook model. 1. Introduction Predicting the machined surface integrity and durability is of prime interest while producing components destined to critical applications requiring high safety and endurance levels such as nuclear energy. Researchers have performed several and various models for metal cutting simulations. However, it is worth to notice that their accuracy to predict the machining performance (including surface integrity) is tightly related to the effectiveness of these models in representing the actual metal cutting process (Jawahir et al. 2011) (Outeiro et al. 2015a). In fact, such models are sensitive to several factors, including the description of the work material behavior during the cutting process, usually represented through a constitutive (material) model. The classical thermo-viscoplastic Johnson and Cook (J-C) constitutive model (Johnson and Cook 1983) is often adopted in metal cutting simulations. Its simplicity in addition to the availability of its parameters for various metals Contents lists available at ScienceDirect
h i g h l i g h t s Different kinds of carbides could appear on a tantalum sample if the carbon f... more h i g h l i g h t s Different kinds of carbides could appear on a tantalum sample if the carbon flux varies on its surface. Epitaxial relationships between Ta, Ta 2 C and TaC are highlighted in tantalum carbide layers. Under specifics carbon flux, TaC carbide layer grow in relation with the Ta substrate. Columnar and equiaxed growths of carbide layers are separated by a carbon boundary flux.
L'impact que peut avoir l'usinage sur la santé matière du produit fini constitue un intérêt indus... more L'impact que peut avoir l'usinage sur la santé matière du produit fini constitue un intérêt industriel et scientifique majeur. Les principaux enjeux sont de prédire la formation du copeau, l'état mécanique et microstructural du matériau usiné et sa résistance à la corrosion. Dans ce travail, nous étudions l'effet de l'usinage en coupe orthogonale (tournage) sur la microstructure (transformation de phase, recristallisation), le comportement mécanique et la résistance à la corrosion en brouillard salin d'un acier inoxydable martensitique. Approches expérimentales et méthodes numériques par éléments finis sont couplées.
Les procédés d'usinage peuvent créer des contraintes résiduelles à la surface des pièces usinées ... more Les procédés d'usinage peuvent créer des contraintes résiduelles à la surface des pièces usinées et ainsi modifier la microstructure et la texture de la matière proche de la surface. De tels changements sont importants pour l'étude du comportement des pièces au cours du temps. Il est alors nécessaire de quantifier les contraintes résiduelles, les composantes de texture et de déterminer la microstructure induite par l'usinage pour comprendre et prédire le comportement des surfaces considérées. Dans cette étude, le matériau cuivre pur a été choisi et considéré comme un "système modèle". En tournage, l'influence du rayon de bec, de la vitesse de coupe et de la présence de lubrifiant sur le champ de contraintes et la texture a été quantifiée à l'aide de techniques DRX. Les modifications microstructurales ont été évaluées à l'aide de la microscopie électronique à balayage. Enfin, le comportement électrochimique de la surface a été étudié en utilisant la technique de la micro-cellule électrochimique.
Superfinishing machining has a particular impact on cutting mechanics, surface integrity and loca... more Superfinishing machining has a particular impact on cutting mechanics, surface integrity and local electrochemical behavior. In fact, material removal during this process induces geometrical, mechanical and micro-structural modifications in the machined surface and sub-surface. However, a conventional 3D cutting process is still complex to study in terms of analytical/numerical modeling and experimental process monitoring. So, researchers are wondering if a less intricate configuration such as orthogonal cutting would be able to provide information about surface integrity as close as possible to that one generated by a 3D cutting process. For that reason, in the present paper, two different machining configurations were compared: face turning and orthogonal cutting. The work material is oxygen free high conductivity copper (OFHC) and the cutting tools are uncoated cemented carbide. The research work was performed in three steps. In the first step, the process mechanics of superfinishing machining of OFHC copper was performed. In the second step, the surface integrity and the chemical behavior of the machined samples were analyzed. Finally, in the third step, correlations between input parameters and output measures were conducted using statistical techniques. Results show that when applying low ratios between the uncut chip thickness and the cutting edge radius, the surface integrity and cutting energy are highly affected by the ploughing phenomenon. Otherwise, the most relevant cutting parameter is the feed. In order to compare face turning with orthogonal cutting, a new geometrical parameter was introduced, which has a strong effect in the electrochemical behavior of the machined surface. Selection and/or peer-review under responsibility of The International Scientific Committee of the 2 nd CIRP Conference on Surface Integrity in the person of the Conference Chair Prof. Dragos Axinte
The interaction of water molecules on a nickel surface was studied using ReaxFF (reactive force f... more The interaction of water molecules on a nickel surface was studied using ReaxFF (reactive force field) molecular dynamics.This approach was originally developed by van Duinet al.to study the hydrocarbon chemistry and the catalytic properties of organic compounds. To our knowledge, this method has not been used to study the corrosion processes of nickel exposed to water, which is what we set out to achieve in the present investigation. To do so, calculations were first performed using ReaxFF in order to reproduce certain well-known properties of pure nickel and nickel-water systems. This allowed us to study the adsorption of a single water molecule interacting with an optimized nickel surface. We also investigated the interaction of 405 molecules of water (ρ=0.99 g.cm-3) on the (100), (110) and (111) surfaces of a single crystal of nickel at 300 K. The results show that a water bilayer is adsorbed on nickel surfaces: the first water layer is directly bonded to the surface, whereas th...
We investigated the oxidation of nanocrystalline aluminum surfaces by using variable charge molec... more We investigated the oxidation of nanocrystalline aluminum surfaces by using variable charge molecular dynamics at 600 K under three oxygen pressures: 1, 10 and 20 atm. The interaction potential was described by the electrostatic plus (Es+) model that allows dynamical charge transfer among atoms. We mainly focused on the effect of the oxygen pressure on the oxidation kinetic, the chemical composition and the microstructure of the oxide films formed. The results show that oxidation kinetics as well as chemical composition and microstructure depend on the applied oxygen pressure. The oxide film thickness tends to a limiting value equal to ~3 nm. Finally, we obtained a partially crystalline oxide films for all oxygen pressures and we observed that the degree of crystallinity increases with time.
Stabilized austenitic stainless steels are widely used in nuclear and oil industries. The 316 Nb ... more Stabilized austenitic stainless steels are widely used in nuclear and oil industries. The 316 Nb steel grade presented in this study holds a small amount of delta ferrite in the austenitic matrix which tends to transform into sigma phase during prolonged exposures in the temperature range of 600-1000°C. Sigma phase is promoted by ferritic elements such as chromium, molybdenum, niobium and silicon. Time-Temperature-Transformation (TTT) diagram of the δ-ferrite evolution is established thanks to DSC experiments and quantitative metallographic analysis. It is observed that the highest sigma phase formation rate occurs between 800 and 900°C, and that the transformation of ferrite begins after a few minutes of exposure in this temperature range. The microstructure of transformed δ-ferrite is mostly dominated by the eutectoid mixture σ + γ2. Tensile tests were performed for three different cooling conditions: a significant embrittlement attributed to the δ-ferrite transformation is measur...
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
We investigate the oxidation of nanocrystalline aluminum surfaces using molecular dynamics (MD) s... more We investigate the oxidation of nanocrystalline aluminum surfaces using molecular dynamics (MD) simulations with the variable charge model that allows charge dynamically transfer among atoms. The interaction potential between atoms is described by the electrostatic plus (Es+) potential model, which is composed of an embedded atom method potential and an electrostatic term. The simulations were performed from 300 to 750K on polycrystalline samples with a mean grain size of 5 nanometers. We mainly focused on the effect of the temperature parameter on the oxidation kinetic. The results show that, beyond a first linear regime, the kinetics follow a direct logarithmic law (governed by diffusion process) and tend to a limiting value corresponding to a thickness of ~3nm. We also characterized at 600K the effects of an external applied strain on the microstructure and the chemical composition of the oxide films formed at the surface. In particular, we obtained a partially crystalline oxide films for all temperature and we noticed a strong correlation between the degree of crystallinity of the oxide film and the oxidation temperature.
In the present paper, grid points coupled with an image analysis method are used to map strain gr... more In the present paper, grid points coupled with an image analysis method are used to map strain gradients within grains and across interfaces of duplex stainless steels at the micro-and nanoscale under straining conditions (4.5% plastic strain). Highly heterogeneous strain field are obtained and sites where high strain gradients exist are identified. Local electrochemical measurements are then performed in NaCl-based media within these sites by means of the electrochemical microcell technique and 20 µm microcapillaries in order to propose new mechanical-electrochemical criteria leading to a significant enhancement of anodic and/or cathodic reactions and pitting susceptibility of deformed materials.
The influence of residual surface stresses generated by polishing on the pitting susceptibility o... more The influence of residual surface stresses generated by polishing on the pitting susceptibility of duplex stainless steels was studied by combining microelectrochemical measurements with thermal-mechanical simulation. It has been shown that the surface stress state was the driving force for pit initiation along the austenite/ferrite interface. The local stress gradient was the key-parameter in pit initiation and the local average stress was the parameter governing the transition from metastable to stable pitting.
The aim of this work is to develop a numerical model capable of predicting the grain density in t... more The aim of this work is to develop a numerical model capable of predicting the grain density in the Mg-based matrix phase of an AZ91/SiC composite, as a function of the total mass fraction of the embedded SiC particles. Based on earlier work in a range of alloy systems, we assume an exponential relationship between the grain density and the maximum supercooling during solidification. Analysis of data from cast samples with different thicknesses, and mass fractions of added SiCp, permits conclusions to be drawn on the role of SiCp in increasing grain density. By fitting the data, an empirical nucleation law is derived that can be used in a micro model. Numerical simulation based on the model can predict the grain density of magnesium alloys containing SiC particles, using the mass fraction of the particles as inputs. These predictions are compared with measured data.
This paper describes a model developed to simulate the evolution of carbide layers (TaC/Ta 2 C) f... more This paper describes a model developed to simulate the evolution of carbide layers (TaC/Ta 2 C) formed during carburizing and annealing treatments of tantalum. The model is based on a parabolic evolution of the layer thickness during the growth, and on the carbon conservation during the annealing. In order to validate this model a MATLAB® program was developed. It enables the prediction of the evolution of the tantalum carbide layers (nature and thickness) for a desired treatment defined by a temperature, a carburizing and an annealing duration.
The influence of cutting conditions of a low carbon martensitic stainless steel (15.5wt.% Cr, 4.8... more The influence of cutting conditions of a low carbon martensitic stainless steel (15.5wt.% Cr, 4.8% Ni, 1% Mo, 0.9% Mn, 0.24% Si, 0.1% Cu, < 0.06% C and 77.46% Fe) on the microstructure is first studied using electron backscatter diffraction and transmission electron microscopy. The mechanical and corrosion behaviours of this stainless steel are then investigated. It was found that the microstructure is significantly affected near the machined surface. The formation of grain sub-boundaries or a refinement of the microstructure is observed depending on cutting conditions. Both lead to an increase of the hardness. In addition, the microstructure refinement yields to a huge increase of the average pit surface area. By contrast the average pit density is not affected by machining conditions.
Tribological behavior at both tool/chip and tool/work material interfaces should be highly consid... more Tribological behavior at both tool/chip and tool/work material interfaces should be highly considered while simulating the machining process. In fact, it is no longer accurate to suppose one independent constant friction coefficient at the tool/chip interface, since in reality it depends on the applied contact conditions, including the sliding velocity and pressure. The contact conditions at both above mentioned interfaces may affect the thermal and mechanical phenomena and consequently the surface integrity predictions. In this article, the influence of contact conditions (sliding velocity) on the tribological behavior of uncoated tungsten carbide tool against OFHC copper work material was investigated. Series of tribology tests combined with numerical simulations of the contact process were performed under different sliding speeds and contact pressures, in order to identify the friction coefficient and the heat partition between OFHC copper and tungsten carbide. The friction coefficient in function of the sliding velocity was then integrated into a FE model of the orthogonal cutting of OFHC copper and applied to surface integrity prediction.
Due to the rising interest in predicting machined surface integrity and sustainability, various m... more Due to the rising interest in predicting machined surface integrity and sustainability, various models for metal cutting simulation have been developed. However, their accuracy depends deeply on the physical description of the machining process. This study aims to develop an orthogonal cutting model for surface integrity prediction, which includes a physical-based constitutive model of Oxygen Free High Conductivity (OFHC) copper. This constitutive model incorporates the effects of the state of stress and microstructure on the work material behavior, as well as a dislocation density-based model for surface integrity prediction. The coefficients of the constitutive model were identified through a hybrid experimental/numerical approach, consisting in mechanical tests, numerical simulations and an optimization-based algorithm. The orthogonal cutting model was simulated by FEM, using ALE formulation, and was validated by comparing predicted and measured results, including residual stresses, dislocation density and grain size. The model is then used to analyze the influence of the cutting parameters and cutting geometry on surface integrity, and its results are compared to those obtained by the Johnson-Cook model. 1. Introduction Predicting the machined surface integrity and durability is of prime interest while producing components destined to critical applications requiring high safety and endurance levels such as nuclear energy. Researchers have performed several and various models for metal cutting simulations. However, it is worth to notice that their accuracy to predict the machining performance (including surface integrity) is tightly related to the effectiveness of these models in representing the actual metal cutting process (Jawahir et al. 2011) (Outeiro et al. 2015a). In fact, such models are sensitive to several factors, including the description of the work material behavior during the cutting process, usually represented through a constitutive (material) model. The classical thermo-viscoplastic Johnson and Cook (J-C) constitutive model (Johnson and Cook 1983) is often adopted in metal cutting simulations. Its simplicity in addition to the availability of its parameters for various metals Contents lists available at ScienceDirect
h i g h l i g h t s Different kinds of carbides could appear on a tantalum sample if the carbon f... more h i g h l i g h t s Different kinds of carbides could appear on a tantalum sample if the carbon flux varies on its surface. Epitaxial relationships between Ta, Ta 2 C and TaC are highlighted in tantalum carbide layers. Under specifics carbon flux, TaC carbide layer grow in relation with the Ta substrate. Columnar and equiaxed growths of carbide layers are separated by a carbon boundary flux.
L'impact que peut avoir l'usinage sur la santé matière du produit fini constitue un intérêt indus... more L'impact que peut avoir l'usinage sur la santé matière du produit fini constitue un intérêt industriel et scientifique majeur. Les principaux enjeux sont de prédire la formation du copeau, l'état mécanique et microstructural du matériau usiné et sa résistance à la corrosion. Dans ce travail, nous étudions l'effet de l'usinage en coupe orthogonale (tournage) sur la microstructure (transformation de phase, recristallisation), le comportement mécanique et la résistance à la corrosion en brouillard salin d'un acier inoxydable martensitique. Approches expérimentales et méthodes numériques par éléments finis sont couplées.
Les procédés d'usinage peuvent créer des contraintes résiduelles à la surface des pièces usinées ... more Les procédés d'usinage peuvent créer des contraintes résiduelles à la surface des pièces usinées et ainsi modifier la microstructure et la texture de la matière proche de la surface. De tels changements sont importants pour l'étude du comportement des pièces au cours du temps. Il est alors nécessaire de quantifier les contraintes résiduelles, les composantes de texture et de déterminer la microstructure induite par l'usinage pour comprendre et prédire le comportement des surfaces considérées. Dans cette étude, le matériau cuivre pur a été choisi et considéré comme un "système modèle". En tournage, l'influence du rayon de bec, de la vitesse de coupe et de la présence de lubrifiant sur le champ de contraintes et la texture a été quantifiée à l'aide de techniques DRX. Les modifications microstructurales ont été évaluées à l'aide de la microscopie électronique à balayage. Enfin, le comportement électrochimique de la surface a été étudié en utilisant la technique de la micro-cellule électrochimique.
Superfinishing machining has a particular impact on cutting mechanics, surface integrity and loca... more Superfinishing machining has a particular impact on cutting mechanics, surface integrity and local electrochemical behavior. In fact, material removal during this process induces geometrical, mechanical and micro-structural modifications in the machined surface and sub-surface. However, a conventional 3D cutting process is still complex to study in terms of analytical/numerical modeling and experimental process monitoring. So, researchers are wondering if a less intricate configuration such as orthogonal cutting would be able to provide information about surface integrity as close as possible to that one generated by a 3D cutting process. For that reason, in the present paper, two different machining configurations were compared: face turning and orthogonal cutting. The work material is oxygen free high conductivity copper (OFHC) and the cutting tools are uncoated cemented carbide. The research work was performed in three steps. In the first step, the process mechanics of superfinishing machining of OFHC copper was performed. In the second step, the surface integrity and the chemical behavior of the machined samples were analyzed. Finally, in the third step, correlations between input parameters and output measures were conducted using statistical techniques. Results show that when applying low ratios between the uncut chip thickness and the cutting edge radius, the surface integrity and cutting energy are highly affected by the ploughing phenomenon. Otherwise, the most relevant cutting parameter is the feed. In order to compare face turning with orthogonal cutting, a new geometrical parameter was introduced, which has a strong effect in the electrochemical behavior of the machined surface. Selection and/or peer-review under responsibility of The International Scientific Committee of the 2 nd CIRP Conference on Surface Integrity in the person of the Conference Chair Prof. Dragos Axinte
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