Pub Date : 2023-05-31DOI: 10.1080/09603409.2023.2219876
Yuchen Cai, Xuteng Xi, Jianqiang Zhang, B. Gleeson, D. Young
ABSTRACT A Ni-25Cr (wt.%) alloy coated with the salts and mixtures of these salts with an industrial coal ash was exposed to Ar-60CO2-20 H2O at 650 °C for 300 h. The alloy without any deposit developed a uniform internal oxidation zone (IOZ) and an external metallic nickel layer surmounted by a thin NiO scale. Salt deposits changed the scale constituents and morphology. Predominantly, a duplex scale of NiO over a Cr2O3 layer grew with an underlying IOZ containing large Cr-rich oxide precipitates. Under a deposit of ash plus salts, the basic reaction morphology was the same as in the gas-only case, but the oxide layer was non-uniform. Local voids were formed within the alloy beneath chloride plus ash deposits. Under ash with sulphates, the alloy formed both partially protected areas and non-protective multi-layered scales. Spherical ash particles were enveloped by NiO in both salt-ash deposits.
{"title":"Effects of salt and ash deposits on corrosion behaviour of Ni-25Cr in Ar-60CO2-20H2O gas at 650 oC","authors":"Yuchen Cai, Xuteng Xi, Jianqiang Zhang, B. Gleeson, D. Young","doi":"10.1080/09603409.2023.2219876","DOIUrl":"https://doi.org/10.1080/09603409.2023.2219876","url":null,"abstract":"ABSTRACT A Ni-25Cr (wt.%) alloy coated with the salts and mixtures of these salts with an industrial coal ash was exposed to Ar-60CO2-20 H2O at 650 °C for 300 h. The alloy without any deposit developed a uniform internal oxidation zone (IOZ) and an external metallic nickel layer surmounted by a thin NiO scale. Salt deposits changed the scale constituents and morphology. Predominantly, a duplex scale of NiO over a Cr2O3 layer grew with an underlying IOZ containing large Cr-rich oxide precipitates. Under a deposit of ash plus salts, the basic reaction morphology was the same as in the gas-only case, but the oxide layer was non-uniform. Local voids were formed within the alloy beneath chloride plus ash deposits. Under ash with sulphates, the alloy formed both partially protected areas and non-protective multi-layered scales. Spherical ash particles were enveloped by NiO in both salt-ash deposits.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"32 1","pages":"260 - 271"},"PeriodicalIF":1.3,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87916732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-17DOI: 10.1080/09603409.2023.2213579
Gea T. van de Kerkhof, Jessica M. Walker, Surabhi Agrawal, S. Clarke, M. Sk, Dominic J. Craske, R. Lindsay, Michael Dowhyj, Ayomide Osundare, Manfred E. Schuster, J. Parker
ABSTRACT Studying chemical reactions in an environment that closely mimics the system’s natural operating conditions can offer crucial insights into dynamic oxidation processes. Transmission Electron Microscopes (TEMs) and X-ray Nanoprobes allow the use of imaging and spectroscopy to access nanoscale chemical and structural information about these processes. However, the controlled operating conditions and constraints make the design and implementation of in situ sample environments challenging. Here, we outline the setup of an in situ liquid sample environment for the Hard X-ray Nanoprobe beamline (I14) at Diamond Light Source. The liquid environment allows for the imaging and spectroscopic analysis of samples exposed to liquid flow, with heating up to 80℃. The capability is demonstrated with an example experiment studying iron corrosion. The design of the sample cell offers the prospect of combining X-ray and electron microscopy for the in situ multi-length scale imaging and spectroscopy of samples in liquid.
{"title":"An in situ liquid environment for synchrotron hard X-ray nanoprobe microscopy","authors":"Gea T. van de Kerkhof, Jessica M. Walker, Surabhi Agrawal, S. Clarke, M. Sk, Dominic J. Craske, R. Lindsay, Michael Dowhyj, Ayomide Osundare, Manfred E. Schuster, J. Parker","doi":"10.1080/09603409.2023.2213579","DOIUrl":"https://doi.org/10.1080/09603409.2023.2213579","url":null,"abstract":"ABSTRACT Studying chemical reactions in an environment that closely mimics the system’s natural operating conditions can offer crucial insights into dynamic oxidation processes. Transmission Electron Microscopes (TEMs) and X-ray Nanoprobes allow the use of imaging and spectroscopy to access nanoscale chemical and structural information about these processes. However, the controlled operating conditions and constraints make the design and implementation of in situ sample environments challenging. Here, we outline the setup of an in situ liquid sample environment for the Hard X-ray Nanoprobe beamline (I14) at Diamond Light Source. The liquid environment allows for the imaging and spectroscopic analysis of samples exposed to liquid flow, with heating up to 80℃. The capability is demonstrated with an example experiment studying iron corrosion. The design of the sample cell offers the prospect of combining X-ray and electron microscopy for the in situ multi-length scale imaging and spectroscopy of samples in liquid.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"219 ","pages":"371 - 375"},"PeriodicalIF":1.3,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72433849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-04DOI: 10.1080/09603409.2023.2205744
Boma Phoebe Norman, Hisham Al Baroudi, A. Potter, S. Mori, N. Simms, Anand Kulkarni, J. Sumner
ABSTRACT Global power consumption is predicted to double by 2050, notably driven by the transportation and energy sectors necessitating limitations of emissions. Due to its compact turbomachinery, better thermal efficiency, and simpler layout, supercritical-CO2 cycles have received attention, with numerous variations proposed (either indirect-fired/closed cycles or direct-fired-open cycles). One technical challenge is degradation pathway quantification of turbine materials in sCO2 as selection is crucial to successfully and economically operate new plants. This requires degradation assessment in representative environments simulating the Allam cycle. Laboratory tests were conducted on a first stage turbine blade alloy, CM247, with either an environmentally resistant coating or bond coat/thermal barrier coat at one atmosphere and 800°C, with potential exposure including (O2, H2O, N2, SO2) for up to 1000 h. Weight change and metallographic measurements tracked scale development. Scanning electron microscopy/energy dispersive X-ray spectroscopy studied scales and internal precipitates. Locations of contaminant element in the CO2-rich environment were investigated.
{"title":"Corrosion of Potential First Stage Blade Materials in Simulated Supercritical CO2","authors":"Boma Phoebe Norman, Hisham Al Baroudi, A. Potter, S. Mori, N. Simms, Anand Kulkarni, J. Sumner","doi":"10.1080/09603409.2023.2205744","DOIUrl":"https://doi.org/10.1080/09603409.2023.2205744","url":null,"abstract":"ABSTRACT Global power consumption is predicted to double by 2050, notably driven by the transportation and energy sectors necessitating limitations of emissions. Due to its compact turbomachinery, better thermal efficiency, and simpler layout, supercritical-CO2 cycles have received attention, with numerous variations proposed (either indirect-fired/closed cycles or direct-fired-open cycles). One technical challenge is degradation pathway quantification of turbine materials in sCO2 as selection is crucial to successfully and economically operate new plants. This requires degradation assessment in representative environments simulating the Allam cycle. Laboratory tests were conducted on a first stage turbine blade alloy, CM247, with either an environmentally resistant coating or bond coat/thermal barrier coat at one atmosphere and 800°C, with potential exposure including (O2, H2O, N2, SO2) for up to 1000 h. Weight change and metallographic measurements tracked scale development. Scanning electron microscopy/energy dispersive X-ray spectroscopy studied scales and internal precipitates. Locations of contaminant element in the CO2-rich environment were investigated.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"7 1","pages":"376 - 384"},"PeriodicalIF":1.3,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88060802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-04DOI: 10.1080/09603409.2023.2208956
Xudong Wang, Zhong-Xi Yang, Peisen Lv, Lirong Liu
ABSTRACT The effects of μ phase and M23C6 carbide on microstructure and creep properties of DD5 single-crystal superalloy during long-term thermal exposure at 1000°C were investigated in detail. It was found that during thermal exposure at 1000°C, the needle-like μ phase and granular M23C6 carbide were mainly precipitated in dendrite arm and interdendritic regions, respectively. The amount of precipitated phases rose with increasing exposure time. Under the condition of 1038ºC/172 MPa, compared with the sample after standard heat treatment, the creep life of sample exposed for 500 h was increased by 38% due to the precipitation of a large number of M23C6 particles, while that exposed for 1000 h was reduced by 60% due to the precipitation of more μ phase and degradation of γ′ phase. Furthermore, tensile stress could also promote the precipitation of μ phase and M23C6 carbide.
{"title":"Effect of precipitation behaviour of μ phase and M23C6 carbide on microstructure and creep properties of DD5 single-crystal superalloy during long-term thermal exposure","authors":"Xudong Wang, Zhong-Xi Yang, Peisen Lv, Lirong Liu","doi":"10.1080/09603409.2023.2208956","DOIUrl":"https://doi.org/10.1080/09603409.2023.2208956","url":null,"abstract":"ABSTRACT The effects of μ phase and M23C6 carbide on microstructure and creep properties of DD5 single-crystal superalloy during long-term thermal exposure at 1000°C were investigated in detail. It was found that during thermal exposure at 1000°C, the needle-like μ phase and granular M23C6 carbide were mainly precipitated in dendrite arm and interdendritic regions, respectively. The amount of precipitated phases rose with increasing exposure time. Under the condition of 1038ºC/172 MPa, compared with the sample after standard heat treatment, the creep life of sample exposed for 500 h was increased by 38% due to the precipitation of a large number of M23C6 particles, while that exposed for 1000 h was reduced by 60% due to the precipitation of more μ phase and degradation of γ′ phase. Furthermore, tensile stress could also promote the precipitation of μ phase and M23C6 carbide.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"130 1","pages":"250 - 258"},"PeriodicalIF":1.3,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90207731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.1080/09603409.2023.2205754
B. Pint, Y.-F. Su, D. Sulejmanovic, R. Pillai
ABSTRACT There is considerable interest in molten chloride salts for several applications including thermal storage and next-generation molten salt reactors (MSRs). Several studies have concluded that Cl salts are highly corrosive to structural materials. Using Oak Ridge National Laboratory’s established methodology, Cl salt compatibility was assessed for candidate Ni-based alloys 230, 600 and 740 H at 600°–800°C in static welded capsules and in flowing thermal convection loop (TCL) salt experiments. Simply drying commercial Cl salt at 550°–650°C and adding~0.05 wt.%Mg was able to produce small specimen mass changes and limited surface attack after 100–1000 h exposures. Intentional additions of H2O, NiCl2 and undried salt were used to better understand the role of impurities and achieve the>50 µm levels of attack reported in other studies. Characterisation of Cr depletion and oxide formation in conjunction with pre- and post-test salt chemistry measurements are being used to understand salt compatibility of structural materials.
{"title":"Characterization of Fe and Cr Dissolution and Reaction Product Formation in Molten Chloride Salts With and Without Impurities","authors":"B. Pint, Y.-F. Su, D. Sulejmanovic, R. Pillai","doi":"10.1080/09603409.2023.2205754","DOIUrl":"https://doi.org/10.1080/09603409.2023.2205754","url":null,"abstract":"ABSTRACT There is considerable interest in molten chloride salts for several applications including thermal storage and next-generation molten salt reactors (MSRs). Several studies have concluded that Cl salts are highly corrosive to structural materials. Using Oak Ridge National Laboratory’s established methodology, Cl salt compatibility was assessed for candidate Ni-based alloys 230, 600 and 740 H at 600°–800°C in static welded capsules and in flowing thermal convection loop (TCL) salt experiments. Simply drying commercial Cl salt at 550°–650°C and adding~0.05 wt.%Mg was able to produce small specimen mass changes and limited surface attack after 100–1000 h exposures. Intentional additions of H2O, NiCl2 and undried salt were used to better understand the role of impurities and achieve the>50 µm levels of attack reported in other studies. Characterisation of Cr depletion and oxide formation in conjunction with pre- and post-test salt chemistry measurements are being used to understand salt compatibility of structural materials.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"80 1","pages":"360 - 370"},"PeriodicalIF":1.3,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77910764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.1080/09603409.2023.2205760
F. Duarte Martinez, A. Syed, K. Dawson, G. Tatlock, N. Morar, M. Kothari, C. Tang, J. Leggett, J. Mason-Flucke, G. Gibson, J. Nicholls, S. Gray, G. Castelluccio
ABSTRACT In the pursuit of more efficient gas turbine engines, components are required to operate for longer times at elevated temperatures. This increased time in service, together with a complex loading regime, can expose the material to environmental attack. This work has demonstrated that the interaction of stress, NaCl and a sulphur-containing environment is critical to cause crack initiation in the early stages of the exposure and accelerated corrosion rates in CMSX-4 at 550°C. The effect of having small concentrations of moisture in the gaseous environment or as water crystallisation in the salt is still to be investigated. A working hypothesis is that the interaction of alkali chlorides with a sulphur-containing atmosphere is the trigger to a self-sustaining cycle where metal chloride formation, vaporisation and oxidation lead to high amounts of hydrogen injection in a rapid manner and, therefore, hydrogen embrittlement.
{"title":"Effect of NaCl and SO2 on the stress corrosion cracking of CMSX-4 at 550°C","authors":"F. Duarte Martinez, A. Syed, K. Dawson, G. Tatlock, N. Morar, M. Kothari, C. Tang, J. Leggett, J. Mason-Flucke, G. Gibson, J. Nicholls, S. Gray, G. Castelluccio","doi":"10.1080/09603409.2023.2205760","DOIUrl":"https://doi.org/10.1080/09603409.2023.2205760","url":null,"abstract":"ABSTRACT In the pursuit of more efficient gas turbine engines, components are required to operate for longer times at elevated temperatures. This increased time in service, together with a complex loading regime, can expose the material to environmental attack. This work has demonstrated that the interaction of stress, NaCl and a sulphur-containing environment is critical to cause crack initiation in the early stages of the exposure and accelerated corrosion rates in CMSX-4 at 550°C. The effect of having small concentrations of moisture in the gaseous environment or as water crystallisation in the salt is still to be investigated. A working hypothesis is that the interaction of alkali chlorides with a sulphur-containing atmosphere is the trigger to a self-sustaining cycle where metal chloride formation, vaporisation and oxidation lead to high amounts of hydrogen injection in a rapid manner and, therefore, hydrogen embrittlement.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"51 1","pages":"283 - 295"},"PeriodicalIF":1.3,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87262631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The fatigue and creep–fatigue properties of 316SS formed by selective laser melting (SLM) were investigated, considering the effects of different peak stresses, stress rates and peak-holding times on the ratcheting and creep-ratcheting behaviour of SLM 316 SS specimens at different sampling angles (0°, 90°) and high temperatures (550°C, 650°C, 750°C). Results show that the 90° specimens exhibited better fatigue life than that of the 0° specimens. Moreover, the ratcheting evolution can be divided into three stages, but the first stage is very short and the main ratcheting behaviour takes place in the second and third stages. Interestingly, it was found that at stress rates above 10 MPa/s, the ratcheting evolution curves are highly overlapping. Furthermore, the creep–fatigue interaction promotes the evolution of material damage. Besides, creep increases the total strain of 316SS even with a short dwell time (0.5 min).
{"title":"Low cycle fatigue and creep–fatigue performance of 316SS formed by selective laser melting","authors":"Lingfeng Pan, Peishan Ding, Dezhou Kong, Lijun Liu, Xiaotao Zheng","doi":"10.1080/09603409.2023.2205761","DOIUrl":"https://doi.org/10.1080/09603409.2023.2205761","url":null,"abstract":"ABSTRACT The fatigue and creep–fatigue properties of 316SS formed by selective laser melting (SLM) were investigated, considering the effects of different peak stresses, stress rates and peak-holding times on the ratcheting and creep-ratcheting behaviour of SLM 316 SS specimens at different sampling angles (0°, 90°) and high temperatures (550°C, 650°C, 750°C). Results show that the 90° specimens exhibited better fatigue life than that of the 0° specimens. Moreover, the ratcheting evolution can be divided into three stages, but the first stage is very short and the main ratcheting behaviour takes place in the second and third stages. Interestingly, it was found that at stress rates above 10 MPa/s, the ratcheting evolution curves are highly overlapping. Furthermore, the creep–fatigue interaction promotes the evolution of material damage. Besides, creep increases the total strain of 316SS even with a short dwell time (0.5 min).","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"25 1","pages":"230 - 240"},"PeriodicalIF":1.3,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82216292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-27DOI: 10.1080/09603409.2023.2205763
C. Liu, Tao Chen, Zhigang Wu, Xinglei Wang, H. Luo, Jiantao Wang
ABSTRACT The carburising tests were carried out at 1100 ℃ for 50 h, 100 h, 150 h and 200 h for a new type of tungsten-aluminium alloyed ethylene cracking furnace tube. The composition, microstructure transformation and performance of furnace tubes were analysed. The results showed that the average carbon content within 1 mm of the inner wall increased with the prolongation of carburising time. The thickness of carburised layer increased from 0.3 mm to 1.5 mm. The carbides in as cast structure were mainly massive (Cr, Fe, W)23C6 on the outside and fishbone (Cr, Fe, W)7C3 on the inside. During carburising process, the external (Cr, Fe, W)23C6 carbides coarsened and transformed into (Cr, Fe)7C3, and then gradually transformed into (Cr, Fe, W)7C3. Carbide coarsening mainly occurred in internal (Cr, Fe, W)7C3 during carburising. The carbide precipitation and transformation also led to Vickers hardness value of furnace tube increased.
{"title":"Study on the composition, microstructure and properties of new W-Al alloyed ethylene cracking furnace tube under 1100 ℃ carburising test conditions","authors":"C. Liu, Tao Chen, Zhigang Wu, Xinglei Wang, H. Luo, Jiantao Wang","doi":"10.1080/09603409.2023.2205763","DOIUrl":"https://doi.org/10.1080/09603409.2023.2205763","url":null,"abstract":"ABSTRACT The carburising tests were carried out at 1100 ℃ for 50 h, 100 h, 150 h and 200 h for a new type of tungsten-aluminium alloyed ethylene cracking furnace tube. The composition, microstructure transformation and performance of furnace tubes were analysed. The results showed that the average carbon content within 1 mm of the inner wall increased with the prolongation of carburising time. The thickness of carburised layer increased from 0.3 mm to 1.5 mm. The carbides in as cast structure were mainly massive (Cr, Fe, W)23C6 on the outside and fishbone (Cr, Fe, W)7C3 on the inside. During carburising process, the external (Cr, Fe, W)23C6 carbides coarsened and transformed into (Cr, Fe)7C3, and then gradually transformed into (Cr, Fe, W)7C3. Carbide coarsening mainly occurred in internal (Cr, Fe, W)7C3 during carburising. The carbide precipitation and transformation also led to Vickers hardness value of furnace tube increased.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"71 1","pages":"241 - 249"},"PeriodicalIF":1.3,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85894841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-25DOI: 10.1080/09603409.2023.2205666
Narayanan Murali, A. Ghazari, Shiqi Zheng, Kaiyuan Jin, T. Fisher, N. Ghoniem, Xiaochun Li
ABSTRACT The oxidation characteristics of Haynes 282 microtubes measuring 1 mm in diameter and 200 µm thick exposed to CO2 at elevated temperature are reported. After 215 hours at 700°C and 1 atm, a thin, protective chromia scale accumulates up to 2.03 µm from the outer surface, approximately 1% of the thickness, and internal aluminum oxidation is observed 2.59 µm from the inner surface. The results suggest that oxidation is limited by oxygen diffusion through the growing oxide scale layer. The average grain size in the microtube is 10 µm, and it decreases to 5 µm closer to the inner surface. Severe plastic deformation and variable dynamic recovery and recrystallization from the manufacturing process were observed throughout the microtube. Overall grain size and distribution in the microtube were found to be independent of thermal exposure, despite the occurrence of recrystallization. The superalloy microtube geometry shows promising performance in high-temperature thermal applications.
{"title":"High-temperature oxidation of Haynes 282 microtubes in CO2","authors":"Narayanan Murali, A. Ghazari, Shiqi Zheng, Kaiyuan Jin, T. Fisher, N. Ghoniem, Xiaochun Li","doi":"10.1080/09603409.2023.2205666","DOIUrl":"https://doi.org/10.1080/09603409.2023.2205666","url":null,"abstract":"ABSTRACT The oxidation characteristics of Haynes 282 microtubes measuring 1 mm in diameter and 200 µm thick exposed to CO2 at elevated temperature are reported. After 215 hours at 700°C and 1 atm, a thin, protective chromia scale accumulates up to 2.03 µm from the outer surface, approximately 1% of the thickness, and internal aluminum oxidation is observed 2.59 µm from the inner surface. The results suggest that oxidation is limited by oxygen diffusion through the growing oxide scale layer. The average grain size in the microtube is 10 µm, and it decreases to 5 µm closer to the inner surface. Severe plastic deformation and variable dynamic recovery and recrystallization from the manufacturing process were observed throughout the microtube. Overall grain size and distribution in the microtube were found to be independent of thermal exposure, despite the occurrence of recrystallization. The superalloy microtube geometry shows promising performance in high-temperature thermal applications. ","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"105 1","pages":"218 - 229"},"PeriodicalIF":1.3,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77346803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-11DOI: 10.1080/09603409.2023.2201713
Jinquan Guo, Chao Tang, Fang Wang, K. Liu, Jingwei Zhang, H. Lai
ABSTRACT Q245R steel has good heat and corrosion resistant and is used in various applications, such as reactors, regenerators, reformed gas steam generators, and other equipment. In this study, the creep behaviour of Q245R steel at the temperature of 550 ℃ is investigated. In addition to the modified Kachanov-Robotnov (K-R) method, the traditional and modified θ projection methods were employed to establish the creep constitutive equations of Q245R steel. The results revealed that at small strains, the creep prediction curve was in good agreement with the test curve, and the prediction accuracy of the modified θ projection method was better than that of the other two models.
{"title":"Creep behaviour of Q245R steel at 550 ℃","authors":"Jinquan Guo, Chao Tang, Fang Wang, K. Liu, Jingwei Zhang, H. Lai","doi":"10.1080/09603409.2023.2201713","DOIUrl":"https://doi.org/10.1080/09603409.2023.2201713","url":null,"abstract":"ABSTRACT Q245R steel has good heat and corrosion resistant and is used in various applications, such as reactors, regenerators, reformed gas steam generators, and other equipment. In this study, the creep behaviour of Q245R steel at the temperature of 550 ℃ is investigated. In addition to the modified Kachanov-Robotnov (K-R) method, the traditional and modified θ projection methods were employed to establish the creep constitutive equations of Q245R steel. The results revealed that at small strains, the creep prediction curve was in good agreement with the test curve, and the prediction accuracy of the modified θ projection method was better than that of the other two models.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"30 1","pages":"210 - 217"},"PeriodicalIF":1.3,"publicationDate":"2023-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87718868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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