Articles de revista
http://hdl.handle.net/2117/3136
2024-03-28T22:01:39ZStudy on the formability and texture evolution of AA6061 alloy processed by repetitive corrugation and straightening
http://hdl.handle.net/2117/358678
Study on the formability and texture evolution of AA6061 alloy processed by repetitive corrugation and straightening
Elizalde Huitrón, Sergio Alberto; Ezequiel Alvarado, Marco Alejandro; Cabrera Marrero, José M.; Figueroa, I. A.; Baile Puig, Maria Teresa
The enhanced mechanical properties obtained by refining the grain size down to the ultrafine-grained (UFG) regime have attracted considerable attention in recent years. The severe plastic deformation (SPD) techniques allow obtaining ultrafine-grained materials. Different SPD techniques permit processing sheet shape materials such as repetitive corrugation and straightening (RCS) and accumulative roll bonding (ARB). In this study, the formability of an AA 6061-T6 processed by RCS was evaluated. The forming limit diagrams (FLD) were obtained by Nakazima tests of samples in initial condition (T6 state) and after one and two RCS cycles. The FLD curves showed that the forming capacity decreased from the first RCS cycle. Likewise, uniaxial tensile tests at different temperatures and strain rates were conducted to analyze the effect of the RCS process on the strain rate sensitivity. They showed a relatively high strain rate sensitivity coefficient in the samples after one and two RCS cycles, which indicates an improvement of i) the capacity of the material to delay the onset of the necking and ii) the formability at increasing temperatures. Finally, texture analysis was carried out employing X-ray diffraction, calculating the orientation distribution functions (ODFs). The initial texture showed a predominant cube texture component, whereas, for further RCS cycles, a weakening of the cube texture and an increment of the S texture component were observed.
2021-12-16T13:09:03ZElizalde Huitrón, Sergio AlbertoEzequiel Alvarado, Marco AlejandroCabrera Marrero, José M.Figueroa, I. A.Baile Puig, Maria TeresaThe enhanced mechanical properties obtained by refining the grain size down to the ultrafine-grained (UFG) regime have attracted considerable attention in recent years. The severe plastic deformation (SPD) techniques allow obtaining ultrafine-grained materials. Different SPD techniques permit processing sheet shape materials such as repetitive corrugation and straightening (RCS) and accumulative roll bonding (ARB). In this study, the formability of an AA 6061-T6 processed by RCS was evaluated. The forming limit diagrams (FLD) were obtained by Nakazima tests of samples in initial condition (T6 state) and after one and two RCS cycles. The FLD curves showed that the forming capacity decreased from the first RCS cycle. Likewise, uniaxial tensile tests at different temperatures and strain rates were conducted to analyze the effect of the RCS process on the strain rate sensitivity. They showed a relatively high strain rate sensitivity coefficient in the samples after one and two RCS cycles, which indicates an improvement of i) the capacity of the material to delay the onset of the necking and ii) the formability at increasing temperatures. Finally, texture analysis was carried out employing X-ray diffraction, calculating the orientation distribution functions (ODFs). The initial texture showed a predominant cube texture component, whereas, for further RCS cycles, a weakening of the cube texture and an increment of the S texture component were observed.Formability of the 5754-aluminum alloy deformed by a modified repetitive corrugation and straightening process
http://hdl.handle.net/2117/180291
Formability of the 5754-aluminum alloy deformed by a modified repetitive corrugation and straightening process
Ezequiel Alvarado, Marco Alejandro; Elizalde Huitrón, Sergio Alberto; Cabrera Marrero, José M.; Picas Barrachina, Josep Anton; Figueroa, I. A.; Alfonso, Ismeli; González, Gonzalo
Sheets of 5754-aluminum alloy processed by a modified repetitive corrugation and straightening (RCS) process were tested in order to measure their formability. For this purpose, forming limit curves were derived. They showed that the material forming capacity decreased after being processed by RCS. However, they kept good formability in the initial stages of the RCS process. The formability study was complemented with microstructural analysis (derivation of texture) and mechanical tests to obtain the strain-rate sensitivity. The texture analysis was done by employing X-ray diffraction, obtaining pole figures, and the orientation distribution function. It was noticed that the initial texture was conserved after successive RCS passes, but the intensity dropped. RCS process did not induce ß-fiber, contrary to common deformation process. The strain-rate sensitivity coefficient was measured through tensile tests at different temperatures and strain rates; the coefficient of the samples processed after one and two passes were still relatively high, indicating the capacity to delay necking, in agreement with the good formability observed in the initial passes of the RCS process
2020-03-18T08:10:09ZEzequiel Alvarado, Marco AlejandroElizalde Huitrón, Sergio AlbertoCabrera Marrero, José M.Picas Barrachina, Josep AntonFigueroa, I. A.Alfonso, IsmeliGonzález, GonzaloSheets of 5754-aluminum alloy processed by a modified repetitive corrugation and straightening (RCS) process were tested in order to measure their formability. For this purpose, forming limit curves were derived. They showed that the material forming capacity decreased after being processed by RCS. However, they kept good formability in the initial stages of the RCS process. The formability study was complemented with microstructural analysis (derivation of texture) and mechanical tests to obtain the strain-rate sensitivity. The texture analysis was done by employing X-ray diffraction, obtaining pole figures, and the orientation distribution function. It was noticed that the initial texture was conserved after successive RCS passes, but the intensity dropped. RCS process did not induce ß-fiber, contrary to common deformation process. The strain-rate sensitivity coefficient was measured through tensile tests at different temperatures and strain rates; the coefficient of the samples processed after one and two passes were still relatively high, indicating the capacity to delay necking, in agreement with the good formability observed in the initial passes of the RCS processElastic asymmetry of PLA material in FDM-printed parts: considerations concerning experimental characterisation for use in numerical simulations
http://hdl.handle.net/2117/174682
Elastic asymmetry of PLA material in FDM-printed parts: considerations concerning experimental characterisation for use in numerical simulations
Pastor Artigues, María Magdalena; Roure Fernández, Francisco; Ayneto Gubert, Javier; Bonada Bo, Jordi; Pérez Guindal, Elsa; Buj Corral, Irene
The objective of this research is to characterise the material poly lactic acid (PLA), printed by fused deposition modelling (FDM) technology, under three loading conditions—tension, compression and bending—in order to get data that will allow to simulate structural components. In the absence of specific standards for materials manufactured in FDM technology, characterisation is carried out based on ASTM International standards D638, D695 and D790, respectively. Samples manufactured with the same printing parameters have been built and tested; and the tensile, compressive and flexural properties have been determined. The influences of the cross-sectional shape and the specimen length on the strength and elastic modulus of compression are addressed. By analysing the mechanical properties obtained in this way, the conclusion is that they are different, are not coherent with each other, and do not reflect the bimodular nature (different behaviour of material in tension and compression) of this material. A finite element (FE) model is used to verify these differences, including geometric non-linearity, to realistically reproduce conditions during physical tests. The main conclusion is that the test methods currently used do not guarantee a coherent set of mechanical properties useful for numerical simulation, which highlights the need to define new characterisation methods better adapted to the behaviour of FDM-printed PLA
2020-01-13T12:03:07ZPastor Artigues, María MagdalenaRoure Fernández, FranciscoAyneto Gubert, JavierBonada Bo, JordiPérez Guindal, ElsaBuj Corral, IreneThe objective of this research is to characterise the material poly lactic acid (PLA), printed by fused deposition modelling (FDM) technology, under three loading conditions—tension, compression and bending—in order to get data that will allow to simulate structural components. In the absence of specific standards for materials manufactured in FDM technology, characterisation is carried out based on ASTM International standards D638, D695 and D790, respectively. Samples manufactured with the same printing parameters have been built and tested; and the tensile, compressive and flexural properties have been determined. The influences of the cross-sectional shape and the specimen length on the strength and elastic modulus of compression are addressed. By analysing the mechanical properties obtained in this way, the conclusion is that they are different, are not coherent with each other, and do not reflect the bimodular nature (different behaviour of material in tension and compression) of this material. A finite element (FE) model is used to verify these differences, including geometric non-linearity, to realistically reproduce conditions during physical tests. The main conclusion is that the test methods currently used do not guarantee a coherent set of mechanical properties useful for numerical simulation, which highlights the need to define new characterisation methods better adapted to the behaviour of FDM-printed PLACharacterization of duplex coating system (HVOF plus PVD) on light alloy substrates
http://hdl.handle.net/2117/127644
Characterization of duplex coating system (HVOF plus PVD) on light alloy substrates
Picas Barrachina, Josep Anton; Menargues Muñoz, Sergi; Martín Fuentes, Enrique; Colominas Guardia, Carles; Baile Puig, Maria Teresa
Light metals such as aluminium or magnesium alloys play an important role in many different industrial applications. However, aluminium and especially magnesium alloys show relatively poor resistance to sliding wear, low hardness and load bearing capacity, so that surface performance improvement is recommended, often by PVD processes.
This study evaluates the tribological improvement achieved by applying a duplex coating on AW-7022 aluminium alloy or AZ91 magnesium alloy substrates, consisting of a thick coating interlayer, deposited by High Velocity Oxygen Fuel (HVOF), followed by a PVD (TiN, TiAlN) or PE-CVD (DLC) hard top layers.
The deposition of thermal sprayed HVOF coatings, as primary layer, leads to improvement of the load bearing capacity of the substrates and allows reducing the tendency of hard thin top layer to cracking and delamination when it is directly deposited on a softer substrate. The number of laps to failure, in the pin-on-disc wear tests, of TiN and TiAlN PVD coatings deposited on the harder interlayer HVOF coating were significantly higher (3000 and 1400 laps, respectively) than the values measured for these coatings deposited directly on the aluminium substrate (140 and 120 laps, respectively).
The best combination of properties was obtained with the DLC top layer deposited on the thermally sprayed coatings, with a significant reduction of friction coefficient (< 0.10), which remains almost unchanged even after 40,000 laps in the pin-on-disc wear tests.
2019-01-28T09:00:36ZPicas Barrachina, Josep AntonMenargues Muñoz, SergiMartín Fuentes, EnriqueColominas Guardia, CarlesBaile Puig, Maria TeresaLight metals such as aluminium or magnesium alloys play an important role in many different industrial applications. However, aluminium and especially magnesium alloys show relatively poor resistance to sliding wear, low hardness and load bearing capacity, so that surface performance improvement is recommended, often by PVD processes.
This study evaluates the tribological improvement achieved by applying a duplex coating on AW-7022 aluminium alloy or AZ91 magnesium alloy substrates, consisting of a thick coating interlayer, deposited by High Velocity Oxygen Fuel (HVOF), followed by a PVD (TiN, TiAlN) or PE-CVD (DLC) hard top layers.
The deposition of thermal sprayed HVOF coatings, as primary layer, leads to improvement of the load bearing capacity of the substrates and allows reducing the tendency of hard thin top layer to cracking and delamination when it is directly deposited on a softer substrate. The number of laps to failure, in the pin-on-disc wear tests, of TiN and TiAlN PVD coatings deposited on the harder interlayer HVOF coating were significantly higher (3000 and 1400 laps, respectively) than the values measured for these coatings deposited directly on the aluminium substrate (140 and 120 laps, respectively).
The best combination of properties was obtained with the DLC top layer deposited on the thermally sprayed coatings, with a significant reduction of friction coefficient (< 0.10), which remains almost unchanged even after 40,000 laps in the pin-on-disc wear tests.Corrosion mechanism of HVOF thermal sprayed WC-CoCr coatings in acidic chloride media
http://hdl.handle.net/2117/124686
Corrosion mechanism of HVOF thermal sprayed WC-CoCr coatings in acidic chloride media
Picas Barrachina, Josep Anton; Punset Fuste, Miquel; Rupérez de Gracia, Elisa; Menargues Muñoz, Sergi; Martín Fuentes, Enrique; Baile Puig, Maria Teresa
HVOF thermal sprayed WC cermet coatings exhibit excellent abrasive and erosive wear resistance due to the presence of high volume fraction of WC particles bounded by a tough cobalt or cobalt-chromium alloy binder. However, less information is at present available on the corrosion response of these coatings in strong acidic environment. In this study, the corrosion behaviour of the HVOF WC-CoCr coatings was investigated by electrochemical polarization technique in 0.1¿N hydrochloric (HCl) acid solution at 25¿°C. The coating morphology was studied by scanning electron microscopy (SEM) and the relationships between the microstructure and corrosion mechanism were investigated using small-angle X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy measurements. The analysis of the corroded coating surface showed that during anodic polarization, the corrosion attack of the WC-CoCr coating began with active oxidation of the binder phase followed by the formation of a pseudo-passive layer composed by anhydrous Cr-oxides (CrO), Co-oxides (CoO/Co3O4) and W-oxides (WO3). At higher potentials the corrosion was governed by the hydration of tungsten oxide (WO3·xH2O) and the extension of the oxidation to the WC particles.
2018-11-20T08:01:56ZPicas Barrachina, Josep AntonPunset Fuste, MiquelRupérez de Gracia, ElisaMenargues Muñoz, SergiMartín Fuentes, EnriqueBaile Puig, Maria TeresaHVOF thermal sprayed WC cermet coatings exhibit excellent abrasive and erosive wear resistance due to the presence of high volume fraction of WC particles bounded by a tough cobalt or cobalt-chromium alloy binder. However, less information is at present available on the corrosion response of these coatings in strong acidic environment. In this study, the corrosion behaviour of the HVOF WC-CoCr coatings was investigated by electrochemical polarization technique in 0.1¿N hydrochloric (HCl) acid solution at 25¿°C. The coating morphology was studied by scanning electron microscopy (SEM) and the relationships between the microstructure and corrosion mechanism were investigated using small-angle X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy measurements. The analysis of the corroded coating surface showed that during anodic polarization, the corrosion attack of the WC-CoCr coating began with active oxidation of the binder phase followed by the formation of a pseudo-passive layer composed by anhydrous Cr-oxides (CrO), Co-oxides (CoO/Co3O4) and W-oxides (WO3). At higher potentials the corrosion was governed by the hydration of tungsten oxide (WO3·xH2O) and the extension of the oxidation to the WC particles.Materiales avanzados para la mejora del comportamiento tribológico catenaria-pantógrafo
http://hdl.handle.net/2117/87973
Materiales avanzados para la mejora del comportamiento tribológico catenaria-pantógrafo
Martín Fuentes, Enrique; Baile Puig, Maria Teresa; Picas Barrachina, Josep Anton; Menargues Muñoz, Sergi
En este artículo se presenta un resumen de la situación actual de la problemática del sistema catenaria-pantógrafo, indicándose los materiales que se utilizan o plantean utilizar. Este trabajo es un compendio de lo presentado en el pasado Smart City Expo World Congres celebrado en Barcelona en noviembre de 2015, dentro del espacio BcnRail de la Plataforma Tecnológica Ferroviaria Española.
2016-06-14T12:06:28ZMartín Fuentes, EnriqueBaile Puig, Maria TeresaPicas Barrachina, Josep AntonMenargues Muñoz, SergiEn este artículo se presenta un resumen de la situación actual de la problemática del sistema catenaria-pantógrafo, indicándose los materiales que se utilizan o plantean utilizar. Este trabajo es un compendio de lo presentado en el pasado Smart City Expo World Congres celebrado en Barcelona en noviembre de 2015, dentro del espacio BcnRail de la Plataforma Tecnológica Ferroviaria Española.Microstructure and properties of aluminum silicon/short fibre carbon composites fabricated by semi-solid thixomixing
http://hdl.handle.net/2117/81025
Microstructure and properties of aluminum silicon/short fibre carbon composites fabricated by semi-solid thixomixing
Akbarzadeh, Ebrahim; Picas Barrachina, Josep Anton; Baile Puig, Maria Teresa
A novel method was developed, based on thixotropic nature of semi-solid slurry of aluminum silicon alloy, for the effective dispersion and distribution of short carbon fibers (Csf) under intensive shear stress (t) into the eutectic without physical or chemical damage. The Csf were distributed homogeneously into the matrix at optimum conditions: a temperature of 576–580 °C, around 48% of solid fraction, and rotation speed of mixing was at 100 rpm. The gas entrapment and porosity was a challenge in the fabrication the aluminum composite by thixomixing, and its size increased when the samples were heat treated. The extruded and heat treated composites had around 24% improvement of mechanical strength as assessed by tensile tests. The predominant deposition of silicon and its intermetallics at the interfacial region improved the wettability and adherence to achieve good mechanical properties. The formation of some intermetallics can be helpful to overcome low wettability effects and their structural evolutions were impressive. The fractography analysis illustrated the ductile fracture with some plastic deformation as the results of dimples and some fiber pull-out in the fractured surface. Ultra-micro hardness evaluation showed good interfacial bonding after heat treatment. The thixomixing process can be developed to produce various composites with different reinforcement.
2015-12-23T11:02:54ZAkbarzadeh, EbrahimPicas Barrachina, Josep AntonBaile Puig, Maria TeresaA novel method was developed, based on thixotropic nature of semi-solid slurry of aluminum silicon alloy, for the effective dispersion and distribution of short carbon fibers (Csf) under intensive shear stress (t) into the eutectic without physical or chemical damage. The Csf were distributed homogeneously into the matrix at optimum conditions: a temperature of 576–580 °C, around 48% of solid fraction, and rotation speed of mixing was at 100 rpm. The gas entrapment and porosity was a challenge in the fabrication the aluminum composite by thixomixing, and its size increased when the samples were heat treated. The extruded and heat treated composites had around 24% improvement of mechanical strength as assessed by tensile tests. The predominant deposition of silicon and its intermetallics at the interfacial region improved the wettability and adherence to achieve good mechanical properties. The formation of some intermetallics can be helpful to overcome low wettability effects and their structural evolutions were impressive. The fractography analysis illustrated the ductile fracture with some plastic deformation as the results of dimples and some fiber pull-out in the fractured surface. Ultra-micro hardness evaluation showed good interfacial bonding after heat treatment. The thixomixing process can be developed to produce various composites with different reinforcement.Thixomixing as novel method for fabrication aluminum composite with carbon and alumina fibers
http://hdl.handle.net/2117/81022
Thixomixing as novel method for fabrication aluminum composite with carbon and alumina fibers
Akbarzadeh, Ebrahim; Picas Barrachina, Josep Anton; Baile Puig, Maria Teresa
This study focuses on a novel method for dispersion
and distribution of reinforcement under high intensive shear stress to
produce metal composites. The polyacrylonitrile (PAN)-based short
carbon fiber (Csf) and Nextel 610 alumina fiber were dispersed under
high intensive shearing at mushy zone in semi-solid of A356 by a
novel method. The bundles and clusters were embedded by
infiltration of slurry into the clusters, thus leading to a uniform
microstructure. The fibers were embedded homogenously into the
aluminum around 576-580°C with around 46% of solid fraction.
Other experiments at 615°C and 568°C which are contained 0% and
90% solid respectively were not successful for dispersion and
infiltration of aluminum into bundles of Csf. The alumina fiber has
been cracked by high shearing load. The morphologies and
crystalline phase were evaluated by SEM and XRD. The adopted
thixo-process effectively improved the adherence and distribution of
Csf into Al that can be developed to produce various composites by
thixomixing.; This study focuses on a novel method for dispersion
and distribution of reinforcement under high intensive shear stress to
produce metal composites. The polyacrylonitrile (PAN)-based short
carbon fiber (Csf) and Nextel 610 alumina fiber were dispersed under
high intensive shearing at mushy zone in semi-solid of A356 by a
novel method. The bundles and clusters were embedded by
infiltration of slurry into the clusters, thus leading to a uniform
microstructure. The fibers were embedded homogenously into the
aluminum around 576-580°C with around 46% of solid fraction.
Other experiments at 615°C and 568°C which are contained 0% and
90% solid respectively were not successful for dispersion and
infiltration of aluminum into bundles of Csf. The alumina fiber has
been cracked by high shearing load. The morphologies and
crystalline phase were evaluated by SEM and XRD. The adopted
thixo-process effectively improved the adherence and distribution of
Csf into Al that can be developed to produce various composites by
thixomixing.
2015-12-23T10:21:49ZAkbarzadeh, EbrahimPicas Barrachina, Josep AntonBaile Puig, Maria TeresaThis study focuses on a novel method for dispersion
and distribution of reinforcement under high intensive shear stress to
produce metal composites. The polyacrylonitrile (PAN)-based short
carbon fiber (Csf) and Nextel 610 alumina fiber were dispersed under
high intensive shearing at mushy zone in semi-solid of A356 by a
novel method. The bundles and clusters were embedded by
infiltration of slurry into the clusters, thus leading to a uniform
microstructure. The fibers were embedded homogenously into the
aluminum around 576-580°C with around 46% of solid fraction.
Other experiments at 615°C and 568°C which are contained 0% and
90% solid respectively were not successful for dispersion and
infiltration of aluminum into bundles of Csf. The alumina fiber has
been cracked by high shearing load. The morphologies and
crystalline phase were evaluated by SEM and XRD. The adopted
thixo-process effectively improved the adherence and distribution of
Csf into Al that can be developed to produce various composites by
thixomixing.
This study focuses on a novel method for dispersion
and distribution of reinforcement under high intensive shear stress to
produce metal composites. The polyacrylonitrile (PAN)-based short
carbon fiber (Csf) and Nextel 610 alumina fiber were dispersed under
high intensive shearing at mushy zone in semi-solid of A356 by a
novel method. The bundles and clusters were embedded by
infiltration of slurry into the clusters, thus leading to a uniform
microstructure. The fibers were embedded homogenously into the
aluminum around 576-580°C with around 46% of solid fraction.
Other experiments at 615°C and 568°C which are contained 0% and
90% solid respectively were not successful for dispersion and
infiltration of aluminum into bundles of Csf. The alumina fiber has
been cracked by high shearing load. The morphologies and
crystalline phase were evaluated by SEM and XRD. The adopted
thixo-process effectively improved the adherence and distribution of
Csf into Al that can be developed to produce various composites by
thixomixing.Orthogonal experimental design applied for wear characterization of aluminum/Csf metal composite fabricated by the thixomixing method
http://hdl.handle.net/2117/81017
Orthogonal experimental design applied for wear characterization of aluminum/Csf metal composite fabricated by the thixomixing method
Akbarzadeh, Ebrahim; Picas Barrachina, Josep Anton; Baile Puig, Maria Teresa
High silicon content aluminum alloy (hypereutectic) possess good tribological characteristics with low coefficients of friction, when embedded with short carbon fiber (Csf), making this composite a good material choice where good wear and high strength properties are required in light weight components. There is no previously published information available, to the knowledge of the authors, regarding the influence of wear parameters and their interactions on the tribological behavior of Csf reinforced metal matrix composites. In this study a Taguchi design of experiment (DoE) was conducted to optimize and analyze the effects of the wear parameters on the tribological properties of Al/Csf metal matrix composite. A novel thixomixing method which was used to process the metal within the semisolid state was employed to embed short carbon fibers homogenously into the metal matrix. The influences of the sliding speed, applied load and volume fraction, of Csf on the specific wear rate and coefficient of friction were examined, with each of these input parameters tested at three levels(0, 4.2, 8.1%vol.). The results were indicated that Al/Csf composite had better tribological properties than Al alloy due to which contains carbon as solid lubricant. According to the statistical analysis, the influence of volume fraction of carbon fiber on wear parameters was ranked first; so the load and sliding speed are at the following rankings. The contribution percentage for each parameter was determined by the analysis of variance. The relatively good interfacial adherence of carbon fiber and matrix alloy were demonstrated. The coherent and adherent graphite-rich layer on the worn surface was characterized using scanning electron microscopy (SEM).
2015-12-23T07:57:49ZAkbarzadeh, EbrahimPicas Barrachina, Josep AntonBaile Puig, Maria TeresaHigh silicon content aluminum alloy (hypereutectic) possess good tribological characteristics with low coefficients of friction, when embedded with short carbon fiber (Csf), making this composite a good material choice where good wear and high strength properties are required in light weight components. There is no previously published information available, to the knowledge of the authors, regarding the influence of wear parameters and their interactions on the tribological behavior of Csf reinforced metal matrix composites. In this study a Taguchi design of experiment (DoE) was conducted to optimize and analyze the effects of the wear parameters on the tribological properties of Al/Csf metal matrix composite. A novel thixomixing method which was used to process the metal within the semisolid state was employed to embed short carbon fibers homogenously into the metal matrix. The influences of the sliding speed, applied load and volume fraction, of Csf on the specific wear rate and coefficient of friction were examined, with each of these input parameters tested at three levels(0, 4.2, 8.1%vol.). The results were indicated that Al/Csf composite had better tribological properties than Al alloy due to which contains carbon as solid lubricant. According to the statistical analysis, the influence of volume fraction of carbon fiber on wear parameters was ranked first; so the load and sliding speed are at the following rankings. The contribution percentage for each parameter was determined by the analysis of variance. The relatively good interfacial adherence of carbon fiber and matrix alloy were demonstrated. The coherent and adherent graphite-rich layer on the worn surface was characterized using scanning electron microscopy (SEM).Microstructural and tribological studies of as-sprayed and heat-treated HVOF Cr3C2-CoNiCrAlY coatings with a CoNiCrAlY bond coat
http://hdl.handle.net/2117/80992
Microstructural and tribological studies of as-sprayed and heat-treated HVOF Cr3C2-CoNiCrAlY coatings with a CoNiCrAlY bond coat
Picas Barrachina, Josep Anton; Punset Fuste, Miquel; Menargues Muñoz, Sergi; Martín Fuentes, Enrique; Baile Puig, Maria Teresa
Die wear is an important problem for manufacturers in hot-working processes, e.g. metal die casting, hot extrusion and thixoextrusion of aluminium, magnesium or steel, as well as glass and plastics processing. The dies have to be capable of withstanding complex thermal and mechanical loads, while giving a sufficient wear resistance against abrasiorband adhesion at very high temperatures. In order to improve the wear resistance and reduce the heating of the extrusion die it can be protected with a hard cermet coating. The purpose of this work is to study the high-temperature performance of Cr3C2-CoNiCrAlY coating and explore the potential application of this coating to prolong the life of tooling and dies while reducing maintenance and increasing shelf life and dimensional control. A 75Cr(3)C(2)-25CoNiCrAlY coating with a CoNiCrAlY bond coat was sprayed by HVOF thermal spray process on a steel substrate. Coatings were heat-treated at a range of temperatures between 900 degrees C and 1100 degrees C. The mechanical and tribological properties of coatings were determined as a function of the temperature of heat treatment. The bond coat effect on the thermal shock resistance of Cr3C2-CoNiCrAlY coating was analysed. (C) 2014 Elsevier B.V. All rights reserved.
2015-12-22T12:14:03ZPicas Barrachina, Josep AntonPunset Fuste, MiquelMenargues Muñoz, SergiMartín Fuentes, EnriqueBaile Puig, Maria TeresaDie wear is an important problem for manufacturers in hot-working processes, e.g. metal die casting, hot extrusion and thixoextrusion of aluminium, magnesium or steel, as well as glass and plastics processing. The dies have to be capable of withstanding complex thermal and mechanical loads, while giving a sufficient wear resistance against abrasiorband adhesion at very high temperatures. In order to improve the wear resistance and reduce the heating of the extrusion die it can be protected with a hard cermet coating. The purpose of this work is to study the high-temperature performance of Cr3C2-CoNiCrAlY coating and explore the potential application of this coating to prolong the life of tooling and dies while reducing maintenance and increasing shelf life and dimensional control. A 75Cr(3)C(2)-25CoNiCrAlY coating with a CoNiCrAlY bond coat was sprayed by HVOF thermal spray process on a steel substrate. Coatings were heat-treated at a range of temperatures between 900 degrees C and 1100 degrees C. The mechanical and tribological properties of coatings were determined as a function of the temperature of heat treatment. The bond coat effect on the thermal shock resistance of Cr3C2-CoNiCrAlY coating was analysed. (C) 2014 Elsevier B.V. All rights reserved.