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T Sankara S N Narayanan - One of the best experts on this subject based on the ideXlab platform.
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fretting corrosion of lubricated tin plated Copper Alloy contacts effect of temperature
Tribology International, 2008Co-Authors: T Sankara S N Narayanan, Young-woo ParkAbstract:Abstract The fretting corrosion behaviour of lubricated tin plated Copper Alloy contacts at ambient and elevated temperatures is addressed in this paper. At 27 °C, lubrication is very effective and the contact resistance remains stable for several thousand fretting cycles whereas at elevated temperatures (155 °C) the performance of lubricated contact is not appreciable. Surface profile and surface roughness confirm that the lubricated contacts have a smoother profile and experience a lesser damage at the contact zone at ambient as well as at elevated temperatures. The mechanism of fretting corrosion of tin plated contacts appears to be similar with and without lubrication at all the temperatures studied. The difference in performance of the lubricated contacts at ambient and elevated temperatures is due to the faster wear rate of tin coating at elevated temperatures. Oxidation of the contact zone of the lubricated contacts is prevented at all temperatures studied. The study concludes that lubrication is effective in improving the life of the tin plated Copper Alloy contacts under fretting conditions at ambient temperatures whereas at elevated temperatures lubrication provides only a marginal improvement in performance. The decrease in performance of lubricated tin plated contacts at elevated temperatures is due to the higher wear rate of tin coating and not due to evaporation of the lubricant.
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effect of temperature on the fretting corrosion of tin plated Copper Alloy contacts
Wear, 2007Co-Authors: Young-woo Park, T Sankara S N NarayananAbstract:The effect of temperature on the fretting corrosion behaviour of tin plated Copper Alloy contacts in the temperature range of 25–185 °C, is addressed in this paper. The change in contact resistance with fretting cycles at various temperatures was determined. The contact zone after fretting corrosion test was analyzed using laser scanning microscope, X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectrometry (EDX), to assess the surface profile, phase content, morphology and compositional changes across the interface. The study reveals that temperature has a greater influence on the extent of fretting corrosion of tin plated Copper Alloy contacts. The softening of tin is responsible for the extended region of low contact resistance observed at 85 °C. The increase in thickness and the resistance of Cu–Sn intermetallic compounds (IMCs) is responsible for the decrease in surface roughness and the drastic increase in the contact resistance at higher temperatures. The study suggests that the tin plated Copper Alloy contact system should be considered as Copper Alloy/IMC/Sn/SnO2 instead tin plated Copper Alloy. During fretting corrosion test at elevated temperatures, once the top surface layers are worn out, the contact interface is transformed from tin versus tin-to-tin-intermetallic versus tin-intermetallic. The study concludes that tin plated Copper Alloy contacts are not suitable for high temperature applications.
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effect of temperature on the fretting corrosion of tin plated Copper Alloy contacts
Wear, 2007Co-Authors: Young-woo Park, T Sankara S N NarayananAbstract:The effect of temperature on the fretting corrosion behaviour of tin plated Copper Alloy contacts in the temperature range of 25–185 °C, is addressed in this paper. The change in contact resistance with fretting cycles at various temperatures was determined. The contact zone after fretting corrosion test was analyzed using laser scanning microscope, X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectrometry (EDX), to assess the surface profile, phase content, morphology and compositional changes across the interface. The study reveals that temperature has a greater influence on the extent of fretting corrosion of tin plated Copper Alloy contacts. The softening of tin is responsible for the extended region of low contact resistance observed at 85 °C. The increase in thickness and the resistance of Cu–Sn intermetallic compounds (IMCs) is responsible for the decrease in surface roughness and the drastic increase in the contact resistance at higher temperatures. The study suggests that the tin plated Copper Alloy contact system should be considered as Copper Alloy/IMC/Sn/SnO2 instead tin plated Copper Alloy. During fretting corrosion test at elevated temperatures, once the top surface layers are worn out, the contact interface is transformed from tin versus tin-to-tin-intermetallic versus tin-intermetallic. The study concludes that tin plated Copper Alloy contacts are not suitable for high temperature applications.
Young-woo Park - One of the best experts on this subject based on the ideXlab platform.
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fretting corrosion of lubricated tin plated Copper Alloy contacts effect of temperature
Tribology International, 2008Co-Authors: T Sankara S N Narayanan, Young-woo ParkAbstract:Abstract The fretting corrosion behaviour of lubricated tin plated Copper Alloy contacts at ambient and elevated temperatures is addressed in this paper. At 27 °C, lubrication is very effective and the contact resistance remains stable for several thousand fretting cycles whereas at elevated temperatures (155 °C) the performance of lubricated contact is not appreciable. Surface profile and surface roughness confirm that the lubricated contacts have a smoother profile and experience a lesser damage at the contact zone at ambient as well as at elevated temperatures. The mechanism of fretting corrosion of tin plated contacts appears to be similar with and without lubrication at all the temperatures studied. The difference in performance of the lubricated contacts at ambient and elevated temperatures is due to the faster wear rate of tin coating at elevated temperatures. Oxidation of the contact zone of the lubricated contacts is prevented at all temperatures studied. The study concludes that lubrication is effective in improving the life of the tin plated Copper Alloy contacts under fretting conditions at ambient temperatures whereas at elevated temperatures lubrication provides only a marginal improvement in performance. The decrease in performance of lubricated tin plated contacts at elevated temperatures is due to the higher wear rate of tin coating and not due to evaporation of the lubricant.
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effect of temperature on the fretting corrosion of tin plated Copper Alloy contacts
Wear, 2007Co-Authors: Young-woo Park, T Sankara S N NarayananAbstract:The effect of temperature on the fretting corrosion behaviour of tin plated Copper Alloy contacts in the temperature range of 25–185 °C, is addressed in this paper. The change in contact resistance with fretting cycles at various temperatures was determined. The contact zone after fretting corrosion test was analyzed using laser scanning microscope, X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectrometry (EDX), to assess the surface profile, phase content, morphology and compositional changes across the interface. The study reveals that temperature has a greater influence on the extent of fretting corrosion of tin plated Copper Alloy contacts. The softening of tin is responsible for the extended region of low contact resistance observed at 85 °C. The increase in thickness and the resistance of Cu–Sn intermetallic compounds (IMCs) is responsible for the decrease in surface roughness and the drastic increase in the contact resistance at higher temperatures. The study suggests that the tin plated Copper Alloy contact system should be considered as Copper Alloy/IMC/Sn/SnO2 instead tin plated Copper Alloy. During fretting corrosion test at elevated temperatures, once the top surface layers are worn out, the contact interface is transformed from tin versus tin-to-tin-intermetallic versus tin-intermetallic. The study concludes that tin plated Copper Alloy contacts are not suitable for high temperature applications.
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effect of temperature on the fretting corrosion of tin plated Copper Alloy contacts
Wear, 2007Co-Authors: Young-woo Park, T Sankara S N NarayananAbstract:The effect of temperature on the fretting corrosion behaviour of tin plated Copper Alloy contacts in the temperature range of 25–185 °C, is addressed in this paper. The change in contact resistance with fretting cycles at various temperatures was determined. The contact zone after fretting corrosion test was analyzed using laser scanning microscope, X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectrometry (EDX), to assess the surface profile, phase content, morphology and compositional changes across the interface. The study reveals that temperature has a greater influence on the extent of fretting corrosion of tin plated Copper Alloy contacts. The softening of tin is responsible for the extended region of low contact resistance observed at 85 °C. The increase in thickness and the resistance of Cu–Sn intermetallic compounds (IMCs) is responsible for the decrease in surface roughness and the drastic increase in the contact resistance at higher temperatures. The study suggests that the tin plated Copper Alloy contact system should be considered as Copper Alloy/IMC/Sn/SnO2 instead tin plated Copper Alloy. During fretting corrosion test at elevated temperatures, once the top surface layers are worn out, the contact interface is transformed from tin versus tin-to-tin-intermetallic versus tin-intermetallic. The study concludes that tin plated Copper Alloy contacts are not suitable for high temperature applications.
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Fretting-corrosion mapping of tin-plated Copper Alloy contacts
Wear, 2007Co-Authors: T.s.n. Sankara Narayanan, Young-woo ParkAbstract:The fretting corrosion of tin-plated contacts is influenced by several factors including frequency, amplitude, temperature, humidity, normal load, current load, etc. The present paper aims to develop fretting-corrosion maps to assess the fretting corrosion behaviour of tin-plated Copper Alloy contacts under varying experimental conditions. The extent of change in contact resistance up to 20 000 fretting cycles and the nature of changes, such as, the extent of fretting wear and oxidation, assessed by surface analytical techniques, are used to develop the fretting-corrosion maps. The fretting-corrosion maps are segmented into various zones depending on the predominant processes that occur under a given set of conditions. The proposed fretting-corrosion maps are not quantitative to predict the exact life-time of the contact. However, they will be useful to draw some guidelines about the performance of the tin-plated Copper Alloy contacts under various conditions.
Gunther Reinhart - One of the best experts on this subject based on the ideXlab platform.
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cross contaminations in powder bed fusion influence of Copper Alloy particles in nickel base Alloy feedstock on part quality
Social Science Research Network, 2020Co-Authors: Max Horn, Lukas Langera, Simone Dietrich, Georg Schlick, Christian Seidel, Gunther ReinhartAbstract:When two or more different metal powders are processed on a single additive manufacturing (AM) machine, cross-contaminations can occur. This is particularly relevant to the consecutive processing of different materials on a powder bed fusion (PBF) machine through material changes as well as simultaneous processing of different materials via multi-material PBF. However, uncertainty about tolerable foreign particle percentages in metal powder feedstock limits the applicability of material changes and multi-material PBF. Two Alloys which are of particular relevance to the aerospace industry are nickel-base Alloy 2.4668 and Copper Alloy CW106C. In multi-material applications, 2.4668 mainly serves as a structural, load-bearing material. Therefore, this study investigates the influence of defined quantities of Copper Alloy particles in nickel-base Alloy feedstock on metallurgical structure and static tensile strength. Foreign particle inclusions were dissolved in the matrix material and formed a solid solution. No material deteriorations were observed for contamination levels up to 20 particle percent (part.%). Etching revealed a nonhomogeneous solid solution with Cu-rich areas. Contamination levels up to two particle part.% CW106C in 2.4668 showed no influence on ultimate tensile strength and a limited influence on fracture elongation. At five part.% contamination, both properties deteriorated and inferior material qualities were observed. Fractography showed a similar fracture behavior for all of the contamination levels examined. Implications for the aerospace industry by the material combination examined are made on the basis of the results presented.
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influence of metal powder cross contaminations on part quality in laser powder bed fusion Copper Alloy particles in maraging steel feedstock
Procedia CIRP, 2020Co-Authors: Max Horn, Simone Dietrich, Georg Schlick, Christian Seidel, Gunther Reinhart, Lukas Langer, Mario SchafnitzelAbstract:Abstract Metal powder cross-contaminations are a hindrance in powder-based additive manufacturing (AM). Foreign particles can enter the powder feedstock when two different materials are processed on a single machine – either successively through material changes or simultaneously during multi-material AM. In order to evaluate the criticality of named powder impurities, this study investigates the influence of foreign particle inclusions on part quality during laser powder bed fusion of a material combination commonly processed in multi-material AM: Copper Alloy CW106C particles in maraging steel 1.2709 feedstock. Different contamination levels are examined regarding metallurgical structure, defect formation, and mechanical strength. It is observed that Coppery inclusions are dissolved and do not cause cracks, porosity or other defects below three particle percent. Furthermore, ultimate tensile strength and fracture elongation show a slight negative trend for increasing contamination levels.
Khalid M Imra - One of the best experts on this subject based on the ideXlab platform.
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thermal fatigue behavior of direct metal deposited h13 tool steel coating on Copper Alloy substrate
Surface & Coatings Technology, 2012Co-Authors: Khalid M Imra, Mila And, Sudip Hattacharya, Stefa Gulizia, Mahnaz Jahedi, S H Masood, Jyotirmoy MazumdeAbstract:Abstract Thermal fatigue performance of direct metal deposited H13 tool steel coating on Copper Alloy substrate was investigated for high pressure die casting applications. An innovative thermal fatigue test rig was used which is capable of applying cyclic identical energy on the test materials regardless of thermal conductivity property. H13 tool steel was coated on cylindrical Copper Alloy core material both directly as well as using 316 stainless steel as a buffer layer to evaluate and compare their thermal fatigue properties. Two types of cracks at the surface of both coatings were observed and investigated. The network of small and shallow cracks on the surface was the result of thermal stress while the large catastrophic cracks were believed to be the consequence of thermal stress coupled with the thermal expansion mismatch between the H13 tool steel coating and Copper Alloy core materials. The H13 tool steel, coated with 316 stainless steel showed much less number of cracks compared to the directly coated H13 tool steel indicating superior thermal fatigue resistance. Moreover the first layer of the directly coated H13 tool steel showed vulnerable behavior under high temperature application showing numerous cracks. Both coatings showed no crack propagation along the interface between coatings and the substrate materials.
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direct metal deposition dmd of h13 tool steel on Copper Alloy substrate evaluation of mechanical properties
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011Co-Authors: Khalid M Imra, Mila And, Sudip Hattacharya, S H Masood, Jyotirmoy MazumdeAbstract:Abstract H13 tool steel powder was clad on Copper Alloy substrate both directly and using 41C stainless steel (high Ni steel) powder as a buffer layer by direct metal deposition (DMD). Cu–steel bimetallic die casting and injection molding tools are of high interest for reduction of cycle time by efficient heat extraction due to high thermal conductivity of Copper. The mechanical properties of these bimetallic structures were investigated in terms of bond strength, impact energy and fracture toughness. The bond interfaces of these claddings showed porous and crack free transition regions. The bond strength was higher in the directly clad H13 tool steel compared to the H13 tool steel clad with 41C stainless steel as buffer layer. The fracture morphology in tensile test specimens showed ductile dimple fracture. Presence of necking just below the interface depicted the softening of substrate in heat affected zone (HAZ) during cladding. The Charpy impact energy is little higher in the 41C stainless steel buffered specimens compared to the directly clad H13 tool steel specimens but the fracture toughness results showed reduction of fracture toughness in the 41C stainless steel buffered specimens due to the low strength in the tensile test. However the fracture toughness value was in the ductile region for both deposits.
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influence of process parameters in the direct metal deposition of h13 tool steel on Copper Alloy substrate
World Congress on Engineering, 2010Co-Authors: Khalid M Imra, S H Masood, Mila AndAbstract: Abstract— Bi-metallic die of steel coated on high thermal conductive Copper Alloy is of great interest as mould material for the aluminium high pressure die casting industries. Direct Metal Deposition technique is widely used for laser cladding of steel on Copper substrate. The characteristics of the deposited layer are strongly dependant on the DMD process parameters. Precise selection of the process parameters for a sound deposited layer is a great challenge in this stream. This paper investigates the influence of various process parameters such as laser power, feed rate, powder mass flow rate and focus size on the deposition process. Reflectivity, a common phenomenon associated with laser metal deposition on Copper was the major obstructing factor considered in the experimental procedure. Based on these parametric investigations a suitable set of parameters are suggested for laser cladding of steel on Copper substrate without high reflection that can potentially harm the machine.
Jyotirmoy Mazumde - One of the best experts on this subject based on the ideXlab platform.
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thermal fatigue behavior of direct metal deposited h13 tool steel coating on Copper Alloy substrate
Surface & Coatings Technology, 2012Co-Authors: Khalid M Imra, Mila And, Sudip Hattacharya, Stefa Gulizia, Mahnaz Jahedi, S H Masood, Jyotirmoy MazumdeAbstract:Abstract Thermal fatigue performance of direct metal deposited H13 tool steel coating on Copper Alloy substrate was investigated for high pressure die casting applications. An innovative thermal fatigue test rig was used which is capable of applying cyclic identical energy on the test materials regardless of thermal conductivity property. H13 tool steel was coated on cylindrical Copper Alloy core material both directly as well as using 316 stainless steel as a buffer layer to evaluate and compare their thermal fatigue properties. Two types of cracks at the surface of both coatings were observed and investigated. The network of small and shallow cracks on the surface was the result of thermal stress while the large catastrophic cracks were believed to be the consequence of thermal stress coupled with the thermal expansion mismatch between the H13 tool steel coating and Copper Alloy core materials. The H13 tool steel, coated with 316 stainless steel showed much less number of cracks compared to the directly coated H13 tool steel indicating superior thermal fatigue resistance. Moreover the first layer of the directly coated H13 tool steel showed vulnerable behavior under high temperature application showing numerous cracks. Both coatings showed no crack propagation along the interface between coatings and the substrate materials.
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direct metal deposition dmd of h13 tool steel on Copper Alloy substrate evaluation of mechanical properties
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011Co-Authors: Khalid M Imra, Mila And, Sudip Hattacharya, S H Masood, Jyotirmoy MazumdeAbstract:Abstract H13 tool steel powder was clad on Copper Alloy substrate both directly and using 41C stainless steel (high Ni steel) powder as a buffer layer by direct metal deposition (DMD). Cu–steel bimetallic die casting and injection molding tools are of high interest for reduction of cycle time by efficient heat extraction due to high thermal conductivity of Copper. The mechanical properties of these bimetallic structures were investigated in terms of bond strength, impact energy and fracture toughness. The bond interfaces of these claddings showed porous and crack free transition regions. The bond strength was higher in the directly clad H13 tool steel compared to the H13 tool steel clad with 41C stainless steel as buffer layer. The fracture morphology in tensile test specimens showed ductile dimple fracture. Presence of necking just below the interface depicted the softening of substrate in heat affected zone (HAZ) during cladding. The Charpy impact energy is little higher in the 41C stainless steel buffered specimens compared to the directly clad H13 tool steel specimens but the fracture toughness results showed reduction of fracture toughness in the 41C stainless steel buffered specimens due to the low strength in the tensile test. However the fracture toughness value was in the ductile region for both deposits.