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Détail de l'auteur
Auteur Huang, Xiao
Documents disponibles écrits par cet auteur
Affiner la rechercheEffect of tungsten addition on the nucleation of borides in wide gap brazed joint / Daniel McGuire in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 6 (Juin 2010)
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 6 (Juin 2010) . - 06 p.
Titre : Effect of tungsten addition on the nucleation of borides in wide gap brazed joint Type de document : texte imprimé Auteurs : Daniel McGuire, Auteur ; Huang, Xiao, Auteur ; Doug Nagy, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Brazing Ductility Gas turbines Maintenance engineering Mechanical alloying Superalloys Thermal stress cracking Tungsten Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Wide gap brazing (WGB) is a cost effective and reliable means to repair gas turbine hot section components with defect sizes exceeding 0.3 mm. However, it has been shown that WGB joints of nickel-based superalloys suffer from reduced ductility and thermal fatigue life due to the presence of brittle intermetallics and porosities in the brazed joint. In order to disperse the brittle intermetallic compounds, potentially increase the ductility of the repaired region, and reduce the risk of the thermomechanical fatigue failure, elemental tungsten (W) was added to the braze additive filler alloy IN738 by mechanical alloying. The alloyed IN738 was then brazed with the addition of 30 wt %, 50 wt %, and 80 wt % of braze alloy (BNi-9). After brazing at 1200°C for 20 min, microstructural analysis of WGB joints showed a decreasing trend of discrete boride size and the amount of eutectic and script-shaped borides with the increases of W. The increase in the braze alloy to additive filler alloy ratio diminished the effect of W addition due the dissolution of W particulates. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000006 [...] [article] Effect of tungsten addition on the nucleation of borides in wide gap brazed joint [texte imprimé] / Daniel McGuire, Auteur ; Huang, Xiao, Auteur ; Doug Nagy, Auteur . - 2011 . - 06 p.
Génie Mécanique
Langues : Anglais (eng)
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 6 (Juin 2010) . - 06 p.
Mots-clés : Brazing Ductility Gas turbines Maintenance engineering Mechanical alloying Superalloys Thermal stress cracking Tungsten Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Wide gap brazing (WGB) is a cost effective and reliable means to repair gas turbine hot section components with defect sizes exceeding 0.3 mm. However, it has been shown that WGB joints of nickel-based superalloys suffer from reduced ductility and thermal fatigue life due to the presence of brittle intermetallics and porosities in the brazed joint. In order to disperse the brittle intermetallic compounds, potentially increase the ductility of the repaired region, and reduce the risk of the thermomechanical fatigue failure, elemental tungsten (W) was added to the braze additive filler alloy IN738 by mechanical alloying. The alloyed IN738 was then brazed with the addition of 30 wt %, 50 wt %, and 80 wt % of braze alloy (BNi-9). After brazing at 1200°C for 20 min, microstructural analysis of WGB joints showed a decreasing trend of discrete boride size and the amount of eutectic and script-shaped borides with the increases of W. The increase in the braze alloy to additive filler alloy ratio diminished the effect of W addition due the dissolution of W particulates. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000006 [...]
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 9 (Septembre 2011) . - 07 p.
Titre : Fatigue properties of narrow and wide gap braze repaired joints Type de document : texte imprimé Auteurs : Thomas Henhoeffer, Auteur ; Huang, Xiao, Auteur ; Scott Yandt, Auteur Année de publication : 2012 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Boron alloys Creep testing Fatigue testing Gas turbines Life testing Maintenance engineering Nickel alloys Scanning electron microscopes Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : With the increasing utilization of braze repair in the gas turbine industry, the properties of braze joints under simulated service conditions become vital in selecting braze repair over other processes. While braze repair has often been claimed to deliver mechanical properties equivalent to that of the parent material, this is largely based on the results of tensile or accelerated creep tests for most gas turbine hot section components failure occurs as a result of thermal fatigue or thermomechanical fatigue. The damage that occurs under such conditions cannot be assessed from tensile or creep testing. This study was undertaken to characterize the fatigue properties of narrow and wide gap brazed X-40 cobalt-based superalloy and compare these properties to that of the X-40 parent material. Butt joint narrow gap and wide gap specimens were vacuum brazed using BNi-9 braze alloy. X-40 and IN-738 were used as additive materials in wide gap braze joints. To characterize the fatigue properties of the braze joints and parent material, isothermal fatigue tests were conducted at 950°C and under load control using a fully reversed sinusoidal wave form having stress amplitude of 75% of the yield strength of the parent material. The braze specimens were fatigue tested in the as-brazed condition. The fatigue test results showed that the fatigue lives of the brazed specimens were lower than that of the parent material, particularly for the narrow gap samples and wide gap samples containing IN-738 additive alloy. All fatigue failures in the brazed samples occurred in the braze joints. An analysis of the fracture surfaces using a scanning electron microscope revealed that porosity was the major contributing factor to fatigue failures in the wide gap braze joints. The testing life debit observed in the narrow gap braze samples can be attributed to the presence of brittle boride phases in the braze joint. This study also included examination of techniques for reducing the aforementioned porosity and presence of brittle intermetallic phases. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Fatigue properties of narrow and wide gap braze repaired joints [texte imprimé] / Thomas Henhoeffer, Auteur ; Huang, Xiao, Auteur ; Scott Yandt, Auteur . - 2012 . - 07 p.
Génie Mécanique
Langues : Anglais (eng)
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 9 (Septembre 2011) . - 07 p.
Mots-clés : Boron alloys Creep testing Fatigue testing Gas turbines Life testing Maintenance engineering Nickel alloys Scanning electron microscopes Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : With the increasing utilization of braze repair in the gas turbine industry, the properties of braze joints under simulated service conditions become vital in selecting braze repair over other processes. While braze repair has often been claimed to deliver mechanical properties equivalent to that of the parent material, this is largely based on the results of tensile or accelerated creep tests for most gas turbine hot section components failure occurs as a result of thermal fatigue or thermomechanical fatigue. The damage that occurs under such conditions cannot be assessed from tensile or creep testing. This study was undertaken to characterize the fatigue properties of narrow and wide gap brazed X-40 cobalt-based superalloy and compare these properties to that of the X-40 parent material. Butt joint narrow gap and wide gap specimens were vacuum brazed using BNi-9 braze alloy. X-40 and IN-738 were used as additive materials in wide gap braze joints. To characterize the fatigue properties of the braze joints and parent material, isothermal fatigue tests were conducted at 950°C and under load control using a fully reversed sinusoidal wave form having stress amplitude of 75% of the yield strength of the parent material. The braze specimens were fatigue tested in the as-brazed condition. The fatigue test results showed that the fatigue lives of the brazed specimens were lower than that of the parent material, particularly for the narrow gap samples and wide gap samples containing IN-738 additive alloy. All fatigue failures in the brazed samples occurred in the braze joints. An analysis of the fracture surfaces using a scanning electron microscope revealed that porosity was the major contributing factor to fatigue failures in the wide gap braze joints. The testing life debit observed in the narrow gap braze samples can be attributed to the presence of brittle boride phases in the braze joint. This study also included examination of techniques for reducing the aforementioned porosity and presence of brittle intermetallic phases. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 8 (Août 2011) . - 08 p.
Titre : Investigation of stress assisted grain boundary oxidation cracking in MAR-M002 high pressure turbine blades Type de document : texte imprimé Auteurs : Selvig, Austin, Auteur ; Huang, Xiao, Auteur ; Hildebrand, Mike, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Alumina Blades Cracks Diffusion Engines Gas turbines Grain boundaries Hafnium compounds Oxidation Scanning electron microscopy X-ray chemical analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Modern superalloys have enabled high pressure turbine (HPT) blades in gas turbine engines (GTE) to operate at higher temperatures. Unfortunately, the complexity of these materials can make it difficult to understand the failure mechanisms of these blades. HPT blades made of the nickel-based superalloy Mar-M002 have been found to suffer from stress assisted grain boundary oxidation (SAGBO) cracking. HPT blades removed from an RB211-24C aeroderivative industrial GTE were sectioned, and the cracks and microstructure were studied using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). No cracks were found on the external surface of the blade, which had been coated with an oxidation resistant material. Surface irregularities were found along the walls of the inner cooling channels throughout the entire blade. Larger SAGBO cracks were observed to be near the lower 25% span of the blade and had initiated from the surfaces of the cooling channels. SEM/EDS analyses showed that these cracks had large amounts of alumina and hafnium-rich particles within them. It is evident that these cracks occurred in locations where the combination of high stress and high temperature led to higher rates of oxygen diffusion and subsequent oxidation of grain boundary carbides. Hafnium carbide precipitates along the grain boundaries expanded as they converted into hafnium oxide, thus further increasing the stress. It is envisaged that this increase in stress along the grain boundary has caused the cracks to initiate and coalesce. Based on this observation, it is believed that the inner cooling channels of these HPT blades could benefit from the application of an oxidation resistant coating in order to prevent or delay the formation of these cracks. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Investigation of stress assisted grain boundary oxidation cracking in MAR-M002 high pressure turbine blades [texte imprimé] / Selvig, Austin, Auteur ; Huang, Xiao, Auteur ; Hildebrand, Mike, Auteur . - 2011 . - 08 p.
Génie Mécanique
Langues : Anglais (eng)
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 8 (Août 2011) . - 08 p.
Mots-clés : Alumina Blades Cracks Diffusion Engines Gas turbines Grain boundaries Hafnium compounds Oxidation Scanning electron microscopy X-ray chemical analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Modern superalloys have enabled high pressure turbine (HPT) blades in gas turbine engines (GTE) to operate at higher temperatures. Unfortunately, the complexity of these materials can make it difficult to understand the failure mechanisms of these blades. HPT blades made of the nickel-based superalloy Mar-M002 have been found to suffer from stress assisted grain boundary oxidation (SAGBO) cracking. HPT blades removed from an RB211-24C aeroderivative industrial GTE were sectioned, and the cracks and microstructure were studied using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). No cracks were found on the external surface of the blade, which had been coated with an oxidation resistant material. Surface irregularities were found along the walls of the inner cooling channels throughout the entire blade. Larger SAGBO cracks were observed to be near the lower 25% span of the blade and had initiated from the surfaces of the cooling channels. SEM/EDS analyses showed that these cracks had large amounts of alumina and hafnium-rich particles within them. It is evident that these cracks occurred in locations where the combination of high stress and high temperature led to higher rates of oxygen diffusion and subsequent oxidation of grain boundary carbides. Hafnium carbide precipitates along the grain boundaries expanded as they converted into hafnium oxide, thus further increasing the stress. It is envisaged that this increase in stress along the grain boundary has caused the cracks to initiate and coalesce. Based on this observation, it is believed that the inner cooling channels of these HPT blades could benefit from the application of an oxidation resistant coating in order to prevent or delay the formation of these cracks. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 11 (Novembre 2012) . - 08 p.
Titre : Tribological behaviors of titanium nitride- and chromium-nitride-based physical vapor deposition coating systems Type de document : texte imprimé Auteurs : Feng Cai, Auteur ; Huang, Xiao, Auteur ; Qi Yang, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : gas turbines Langues : Anglais (eng) Mots-clés : TiN- and CrN-based coating systems; microstructures; erosion Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This study investigates the effects of the deposition process and coating composition on microstructural and tribological properties of TiN- and CrN-based coating systems. Coatings were produced using various PVD-based processes—electron beam (EB), cathodic arc (CA), and plasma enhanced magnetron sputtering (PEMS). All coated samples were evaluated for their composition, microstructure, and surface morphology. Coating mechanical properties such as hardness, Young's modulus, and coefficient of friction were also studied and related to their microstructures, wear, and erosion resistances. It was found that hardness (H), Young's modulus (E), and coefficient of friction had impact on both wear and erosion rates. In particular, the H3/E2 ratio was inversely proportional to the specific wear rate. For erosion behavior, higher H3/E2 ratios relate to lower erosion rates at low impingement angles, whereas higher H3/E2 ratios relate to higher erosion rates at high impingement angles. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000011 [...] [article] Tribological behaviors of titanium nitride- and chromium-nitride-based physical vapor deposition coating systems [texte imprimé] / Feng Cai, Auteur ; Huang, Xiao, Auteur ; Qi Yang, Auteur . - 2012 . - 08 p.
gas turbines
Langues : Anglais (eng)
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 11 (Novembre 2012) . - 08 p.
Mots-clés : TiN- and CrN-based coating systems; microstructures; erosion Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This study investigates the effects of the deposition process and coating composition on microstructural and tribological properties of TiN- and CrN-based coating systems. Coatings were produced using various PVD-based processes—electron beam (EB), cathodic arc (CA), and plasma enhanced magnetron sputtering (PEMS). All coated samples were evaluated for their composition, microstructure, and surface morphology. Coating mechanical properties such as hardness, Young's modulus, and coefficient of friction were also studied and related to their microstructures, wear, and erosion resistances. It was found that hardness (H), Young's modulus (E), and coefficient of friction had impact on both wear and erosion rates. In particular, the H3/E2 ratio was inversely proportional to the specific wear rate. For erosion behavior, higher H3/E2 ratios relate to lower erosion rates at low impingement angles, whereas higher H3/E2 ratios relate to higher erosion rates at high impingement angles. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000011 [...]
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 1 (Janvier 2012) . - 17 p.
Titre : Wide gap braze repair of gas turbine blades and vanes : a review Type de document : texte imprimé Auteurs : Huang, Xiao, Auteur ; Warren Miglietti, Auteur Année de publication : 2012 Article en page(s) : 17 p. Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Aerospace components Blades Gas turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Gas turbine blades and vanes in modern gas turbines are subjected to an extremely hostile environment. As such, sophisticated airfoil designs and advanced materials have been developed to meet stringent demands and at the same time, ensure increased performance. Despite the evolution of long-life airfoils, damage still occurs during service thus limiting the useful life of these components. Effective repair of after-service components provides life-cycle cost reduction of engines, and as well, contributes to the preservation of rare elements heavily used in modern superalloys. Among these methods developed in the last four decades for the refurbishment and joining of superalloy components, wide gap brazing (WGB) technology has been increasingly used in the field owing to its ability to repair difficult to weld alloys, to build up substantially damaged areas in one operation, and to provide unlimited compositional choices to enhance the properties of the repaired region. In this paper, the historical development of wide gap repair technology currently used in industry is reviewed. The microstructures and mechanical properties of different WGB joints are compared and discussed. Subsequently, different WGB processes employed at major OEMs are summarized. To conclude this review, future developments in WGB repair of newer generations of superalloys are explored. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000001 [...] [article] Wide gap braze repair of gas turbine blades and vanes : a review [texte imprimé] / Huang, Xiao, Auteur ; Warren Miglietti, Auteur . - 2012 . - 17 p.
Génie mécanique
Langues : Anglais (eng)
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 1 (Janvier 2012) . - 17 p.
Mots-clés : Aerospace components Blades Gas turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Gas turbine blades and vanes in modern gas turbines are subjected to an extremely hostile environment. As such, sophisticated airfoil designs and advanced materials have been developed to meet stringent demands and at the same time, ensure increased performance. Despite the evolution of long-life airfoils, damage still occurs during service thus limiting the useful life of these components. Effective repair of after-service components provides life-cycle cost reduction of engines, and as well, contributes to the preservation of rare elements heavily used in modern superalloys. Among these methods developed in the last four decades for the refurbishment and joining of superalloy components, wide gap brazing (WGB) technology has been increasingly used in the field owing to its ability to repair difficult to weld alloys, to build up substantially damaged areas in one operation, and to provide unlimited compositional choices to enhance the properties of the repaired region. In this paper, the historical development of wide gap repair technology currently used in industry is reviewed. The microstructures and mechanical properties of different WGB joints are compared and discussed. Subsequently, different WGB processes employed at major OEMs are summarized. To conclude this review, future developments in WGB repair of newer generations of superalloys are explored. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000001 [...]
