Pub Date : 2023-04-03DOI: 10.1080/09603409.2023.2195060
F. Abe
ABSTRACT A modified Monkman-Grant equation, which can provide a more accurate means of predicting creep rupture life than the standard Monkman-Grant formula, has been investigated for Gr.92 using creep data in the NIMS Creep Data Sheets at 550 to 750°C. The t r versus minimum creep rate min plot, which is called the Monkman-Grant relation, deviates downward at low stresses and long times. Better correlation of the t r with the min is obtained by the replacement of t r with (t r /ε r), where ε r is the total or rupture strain. The (t r /ε r) is inversely proportional to the min over a wide range of stress, temperature and test duration, and the magnitude of data scattering is only a little bit even at low stresses and long times. The creep life of Gr.92 can be predicted by evaluating the min, together with the ε r evaluated from the stress and or min dependence.
本文利用NIMS蠕变数据表中的蠕变数据，对Gr.92进行了研究。与标准的Monkman-Grant公式相比，修正的Monkman-Grant方程可以提供更准确的预测蠕变断裂寿命的方法。在低应力和长时间条件下，tr与最小蠕变速率最小图(称为Monkman-Grant关系)向下偏离。用(t r /ε r)代替tr可以得到tr与最小应变的更好的相关性，其中ε r为总应变或断裂应变。在较宽的应力、温度和测试时间范围内，(t r /ε r)与最小值成反比，即使在低应力和长时间下，数据散射的幅度也很小。Gr.92的蠕变寿命可以通过求最小值和由应力和最小依赖关系求出的ε r来预测。
{"title":"Creep ductility and modified Monkman-Grant equation for Gr.92 by incorporating total strain","authors":"F. Abe","doi":"10.1080/09603409.2023.2195060","DOIUrl":"https://doi.org/10.1080/09603409.2023.2195060","url":null,"abstract":"ABSTRACT A modified Monkman-Grant equation, which can provide a more accurate means of predicting creep rupture life than the standard Monkman-Grant formula, has been investigated for Gr.92 using creep data in the NIMS Creep Data Sheets at 550 to 750°C. The t r versus minimum creep rate min plot, which is called the Monkman-Grant relation, deviates downward at low stresses and long times. Better correlation of the t r with the min is obtained by the replacement of t r with (t r /ε r), where ε r is the total or rupture strain. The (t r /ε r) is inversely proportional to the min over a wide range of stress, temperature and test duration, and the magnitude of data scattering is only a little bit even at low stresses and long times. The creep life of Gr.92 can be predicted by evaluating the min, together with the ε r evaluated from the stress and or min dependence.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"29 1","pages":"192 - 200"},"PeriodicalIF":1.3,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80663172","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 : 2023-03-29DOI: 10.1080/09603409.2023.2195706
Rungsan Sriwilai, Piyapong Tongsong, Jennarong Tungtrongpairoj, P. Visuttipitukul, Kattareeya Taweesup
ABSTRACT Low-cost Ni-Co alloy coating was performed by electroplating technique to improve the high-temperature corrosion resistance of stainless steel interconnects in solid oxide fuel cells (SOFCs). The effect of plating on the surface morphology, microstructure and composition of Ni-Co alloys was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). The Ni-Co coatings were fabricated at thickness of around two microns and compared at different Ni-Co molar ratios. Corrosion performance of Ni-Co coating was evaluated in a muffle furnace under ambient atmosphere at 800℃ for 110 h. Co2NiO4 spinel oxides and Cr2O3 were found on the Ni-Co coated samples after the oxidation test. Results indicated that steel substrate corrosion protection improved with a low parabolic rate constant of 20 times after Ni-Co alloy electrodeposition coating. A smooth coating layer containing Co2NiO4 oxide with fewer defects promoted high oxidation resistance of the steel samples.
{"title":"Fabrication of Ni-Co film for enhancing the high-temperature corrosion resistance of interconnects in solid oxide fuel cells (SOFCs)","authors":"Rungsan Sriwilai, Piyapong Tongsong, Jennarong Tungtrongpairoj, P. Visuttipitukul, Kattareeya Taweesup","doi":"10.1080/09603409.2023.2195706","DOIUrl":"https://doi.org/10.1080/09603409.2023.2195706","url":null,"abstract":"ABSTRACT Low-cost Ni-Co alloy coating was performed by electroplating technique to improve the high-temperature corrosion resistance of stainless steel interconnects in solid oxide fuel cells (SOFCs). The effect of plating on the surface morphology, microstructure and composition of Ni-Co alloys was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). The Ni-Co coatings were fabricated at thickness of around two microns and compared at different Ni-Co molar ratios. Corrosion performance of Ni-Co coating was evaluated in a muffle furnace under ambient atmosphere at 800℃ for 110 h. Co2NiO4 spinel oxides and Cr2O3 were found on the Ni-Co coated samples after the oxidation test. Results indicated that steel substrate corrosion protection improved with a low parabolic rate constant of 20 times after Ni-Co alloy electrodeposition coating. A smooth coating layer containing Co2NiO4 oxide with fewer defects promoted high oxidation resistance of the steel samples.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"79 1","pages":"201 - 209"},"PeriodicalIF":1.3,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83789756","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 : 2023-03-12DOI: 10.1080/09603409.2023.2188351
S. Mori, Andrew Pidcock, J. Sumner, N. Simms, J. Oakey
ABSTRACT The energy sector will need to employ novel strategies to reduce greenhouse gas emissions, such as the increase of steam temperatures/pressures or the use of low carbon fuels (i.e. biomass). Both cause heat exchanger materials’ degradation issues, due to the formation of more/different corrosive deposits, which requires the use of expensive nickel-based materials or coatings. This paper focuses on the behaviour of three different coatings (HVOF NiCrFeSi, laser clad FeCrAl and Laser Clad NiCrFeSi) deposited on TP347HFG, at 700°C (up to 1000 h exposure). Tests were performed using the ‘deposit recoat’ method (KCl deposit) in simulated biomass combustion environments. Cross-sections were analysed using dimensional metrology, to determine distributions of metal loss and internal damage. Intergranular damage and pits were identified using SEM/EDX. A ‘diffusion cell’ behaviour was observed, which led to depletion of alloying elements from the coating and consequent increase in damage. The results suggested a severe degradation of all coatings.
{"title":"Fireside performance of different coatings in biomass power plant","authors":"S. Mori, Andrew Pidcock, J. Sumner, N. Simms, J. Oakey","doi":"10.1080/09603409.2023.2188351","DOIUrl":"https://doi.org/10.1080/09603409.2023.2188351","url":null,"abstract":"ABSTRACT The energy sector will need to employ novel strategies to reduce greenhouse gas emissions, such as the increase of steam temperatures/pressures or the use of low carbon fuels (i.e. biomass). Both cause heat exchanger materials’ degradation issues, due to the formation of more/different corrosive deposits, which requires the use of expensive nickel-based materials or coatings. This paper focuses on the behaviour of three different coatings (HVOF NiCrFeSi, laser clad FeCrAl and Laser Clad NiCrFeSi) deposited on TP347HFG, at 700°C (up to 1000 h exposure). Tests were performed using the ‘deposit recoat’ method (KCl deposit) in simulated biomass combustion environments. Cross-sections were analysed using dimensional metrology, to determine distributions of metal loss and internal damage. Intergranular damage and pits were identified using SEM/EDX. A ‘diffusion cell’ behaviour was observed, which led to depletion of alloying elements from the coating and consequent increase in damage. The results suggested a severe degradation of all coatings.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"11 1","pages":"348 - 359"},"PeriodicalIF":1.3,"publicationDate":"2023-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81906748","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 : 2023-03-10DOI: 10.1080/09603409.2023.2188355
Manon Waeytens, A. Syed, Tracey Roberts, F. D. Martinez, S. Gray, J. Nicholls
ABSTRACT Alloy material selection for sustainable, efficient, and cost-effective use in components is a key requirement for both power generation and aerospace sectors. Superalloys are manufactured using a combination of different elements, selected carefully to balance mechanical performance and environmental resistance to be used in a variety of different service conditions. Therefore, a fundamental understanding of each element is critical to alloy design. In this paper, the interaction of alloy chemistry, particularly chromium as a corrosion-resistant element along with titanium and molybdenum, and their effect on alloys performance for the relevant gas turbine industries were discussed. Based on the findings, the single-crystal alloy is found to be a better corrosion resistant alloy exhibited higher corrosion resistance in comparison to polycrystal alloys and proved that microstructure has a significant impact on alloy performance. This study also established that molybdenum level in chromia former alloys can significantly enhance the corrosion damage.
{"title":"A microscopy study of nickel-based superalloys performance in type I hot corrosion conditions","authors":"Manon Waeytens, A. Syed, Tracey Roberts, F. D. Martinez, S. Gray, J. Nicholls","doi":"10.1080/09603409.2023.2188355","DOIUrl":"https://doi.org/10.1080/09603409.2023.2188355","url":null,"abstract":"ABSTRACT Alloy material selection for sustainable, efficient, and cost-effective use in components is a key requirement for both power generation and aerospace sectors. Superalloys are manufactured using a combination of different elements, selected carefully to balance mechanical performance and environmental resistance to be used in a variety of different service conditions. Therefore, a fundamental understanding of each element is critical to alloy design. In this paper, the interaction of alloy chemistry, particularly chromium as a corrosion-resistant element along with titanium and molybdenum, and their effect on alloys performance for the relevant gas turbine industries were discussed. Based on the findings, the single-crystal alloy is found to be a better corrosion resistant alloy exhibited higher corrosion resistance in comparison to polycrystal alloys and proved that microstructure has a significant impact on alloy performance. This study also established that molybdenum level in chromia former alloys can significantly enhance the corrosion damage.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"24 1","pages":"272 - 282"},"PeriodicalIF":1.3,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75132509","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 : 2023-03-06DOI: 10.1080/09603409.2023.2182588
M. Lambrecht, G. García-Martin, M. I. Lasanta, M. Miguel, R. Díaz, F. Pérez-Trujillo
ABSTRACT The performance of a concentrated solar power plant is strongly driven by its heat storage capacity and is evolving through the development of new salt mixtures. Molten nitrates, which have already proved their high potential, can be further improved in terms of economic and environmental aspects, with the mitigation of toxic compounds and a higher electricity generation capability. In this work, stability range and energy density characterisations were performed on the nitrate ‘Solar’ salt, along with its life cycle assessment, environmental impact, and cost analysis.
{"title":"Evaluation of the environmental impacts and economical study of Solar Salt in CSP-parabolic trough technology","authors":"M. Lambrecht, G. García-Martin, M. I. Lasanta, M. Miguel, R. Díaz, F. Pérez-Trujillo","doi":"10.1080/09603409.2023.2182588","DOIUrl":"https://doi.org/10.1080/09603409.2023.2182588","url":null,"abstract":"ABSTRACT The performance of a concentrated solar power plant is strongly driven by its heat storage capacity and is evolving through the development of new salt mixtures. Molten nitrates, which have already proved their high potential, can be further improved in terms of economic and environmental aspects, with the mitigation of toxic compounds and a higher electricity generation capability. In this work, stability range and energy density characterisations were performed on the nitrate ‘Solar’ salt, along with its life cycle assessment, environmental impact, and cost analysis.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"51 1","pages":"331 - 337"},"PeriodicalIF":1.3,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81013321","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 : 2023-03-04DOI: 10.1080/09603409.2023.2188356
R. Sandström
ABSTRACT Cavitation is expected to be of equal importance for assessing creep damage during cyclic as during static loading conditions. However, the amount of cavitation data is much more limited in the former case. In particular, two features have been missing: basic models for hysteresis loops and for the formation of cavities during cyclic loading. In this paper, such models are presented and compared with published data for LCF of 1Cr0.5Mo steel. To study the role of the creep–fatigue interaction, the influence of pre-creep as well as LCF cycles with and without hold times were included. Hysteresis loops under these conditions could be well reproduced. A model for nucleation of cavities during creep is adapted to cyclic loading. The total creep strain determined with the help of the loop model could be used to predict the number of cavities during the different LCF loops in an acceptable way.
{"title":"Cavitation during creep-fatigue loading","authors":"R. Sandström","doi":"10.1080/09603409.2023.2188356","DOIUrl":"https://doi.org/10.1080/09603409.2023.2188356","url":null,"abstract":"ABSTRACT Cavitation is expected to be of equal importance for assessing creep damage during cyclic as during static loading conditions. However, the amount of cavitation data is much more limited in the former case. In particular, two features have been missing: basic models for hysteresis loops and for the formation of cavities during cyclic loading. In this paper, such models are presented and compared with published data for LCF of 1Cr0.5Mo steel. To study the role of the creep–fatigue interaction, the influence of pre-creep as well as LCF cycles with and without hold times were included. Hysteresis loops under these conditions could be well reproduced. A model for nucleation of cavities during creep is adapted to cyclic loading. The total creep strain determined with the help of the loop model could be used to predict the number of cavities during the different LCF loops in an acceptable way.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"22 1","pages":"174 - 183"},"PeriodicalIF":1.3,"publicationDate":"2023-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77855879","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 : 2023-03-04DOI: 10.1080/09603409.2023.2188679
S. Holdsworth
In addition, four additional presentations were made in a final Plenary Session (Session 6). Following a Rapporteur overview summary of the MIMA-2 conference proceedings, the MHT MIMA-2 Special Issue contains 7 papers based on presentations made during the course of this conference. Importantly, papers originating from four of the main sessions are included [an eighth paper based on a third session presentation was published in Materials at High Temperatures, 2023, 40(1), 88-98]. For example, the first session, which was concerned with High Temperature Materials Issues, mainly (but not exclusively) covered developments associated with 9Cr-3W3Co-VNbBN (alternatively referred to as MARBN). The MARBN steel was originally developed in Japan by a group headed by Fujio Abe, who has continued to be active in studying the metallurgy of this alloy, and a number of other associated advanced martensitic steels. It was therefore appropriate that the first presentation in the first session of the conference was by Dr Abe, and that the 9Cr-3W-3CoVNbBN alloy played an integral part in the first paper in this Special Issue. In fact, Dr Abe’s paper is more generally concerned with The role of inclusions on the degradation in creep life and rupture ductility of ferritic power plant steels and, more specifically, considers the role of BN, AlN and MnS particles on degradation of the creep properties of 9 to 12%Cr martensitic steels and a 1%Cr bainitic steel at temperatures in the range 550 to 700°C. A second paper from the first session concerns Experience of P93 manifold welding under fabrication conditions, and was by de-Smet, Tang & Bok (of Siemens Energy Heat Transfer Technology). While MARBN is an ASME Code Case variant of P93 (or 9Cr-3W-3Co), the presented evidence indicates that further optimisation of the heat treatment and welding procedures are required in order to attain the required impact toughness properties for weldments of the more generic grade of this steel. The second session was concerned with Plant Life Assessment, with the contribution of Professor Nonaka (of Tohoku University) from the Plenary Session representing the Japanese perspective on this topic. Entitled Activities to advance residual life evaluation techniques for highly aged power plant, Professor Nonaka’s paper concerns the wide ranging activities of a Japanese Materials Sciences Society Working Group and recent developments in techniques being adopted for the life assessment of very old power generation units. Two papers based on presentations from the third session (Plant Inspection and Maintenance) are included. The first by Pascal Decoussemaeker (of GE Power, Switzerland) is concerned with Risk-based life management for steam turbines and generators, and considers the necessary important details of an asset management program to ensure reliable operation over the commercial life of, in particular, steam power plant. The third session presentation of Adam Wojcik (Matelect, UK) et
{"title":"Introduction to MIMA-2 conference special issue","authors":"S. Holdsworth","doi":"10.1080/09603409.2023.2188679","DOIUrl":"https://doi.org/10.1080/09603409.2023.2188679","url":null,"abstract":"In addition, four additional presentations were made in a final Plenary Session (Session 6). Following a Rapporteur overview summary of the MIMA-2 conference proceedings, the MHT MIMA-2 Special Issue contains 7 papers based on presentations made during the course of this conference. Importantly, papers originating from four of the main sessions are included [an eighth paper based on a third session presentation was published in Materials at High Temperatures, 2023, 40(1), 88-98]. For example, the first session, which was concerned with High Temperature Materials Issues, mainly (but not exclusively) covered developments associated with 9Cr-3W3Co-VNbBN (alternatively referred to as MARBN). The MARBN steel was originally developed in Japan by a group headed by Fujio Abe, who has continued to be active in studying the metallurgy of this alloy, and a number of other associated advanced martensitic steels. It was therefore appropriate that the first presentation in the first session of the conference was by Dr Abe, and that the 9Cr-3W-3CoVNbBN alloy played an integral part in the first paper in this Special Issue. In fact, Dr Abe’s paper is more generally concerned with The role of inclusions on the degradation in creep life and rupture ductility of ferritic power plant steels and, more specifically, considers the role of BN, AlN and MnS particles on degradation of the creep properties of 9 to 12%Cr martensitic steels and a 1%Cr bainitic steel at temperatures in the range 550 to 700°C. A second paper from the first session concerns Experience of P93 manifold welding under fabrication conditions, and was by de-Smet, Tang & Bok (of Siemens Energy Heat Transfer Technology). While MARBN is an ASME Code Case variant of P93 (or 9Cr-3W-3Co), the presented evidence indicates that further optimisation of the heat treatment and welding procedures are required in order to attain the required impact toughness properties for weldments of the more generic grade of this steel. The second session was concerned with Plant Life Assessment, with the contribution of Professor Nonaka (of Tohoku University) from the Plenary Session representing the Japanese perspective on this topic. Entitled Activities to advance residual life evaluation techniques for highly aged power plant, Professor Nonaka’s paper concerns the wide ranging activities of a Japanese Materials Sciences Society Working Group and recent developments in techniques being adopted for the life assessment of very old power generation units. Two papers based on presentations from the third session (Plant Inspection and Maintenance) are included. The first by Pascal Decoussemaeker (of GE Power, Switzerland) is concerned with Risk-based life management for steam turbines and generators, and considers the necessary important details of an asset management program to ensure reliable operation over the commercial life of, in particular, steam power plant. The third session presentation of Adam Wojcik (Matelect, UK) et","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"33 1","pages":"99 - 100"},"PeriodicalIF":1.3,"publicationDate":"2023-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85697038","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 : 2023-03-04DOI: 10.1080/09603409.2023.2188681
Dj Allen, K. Asvergren, S. Holdsworth, S. Huysmans, S. Lockyer, D. Robertson, A. Shibli, R. Skelton, A. Tonti, R. Vanstone, K. Yagi
Anodamine-based
Anodamine-based
{"title":"Rapporteur overview summary of the 2nd on-line MIMA international conference concerning high temperature plant: materials, inspection, monitoring & assessment","authors":"Dj Allen, K. Asvergren, S. Holdsworth, S. Huysmans, S. Lockyer, D. Robertson, A. Shibli, R. Skelton, A. Tonti, R. Vanstone, K. Yagi","doi":"10.1080/09603409.2023.2188681","DOIUrl":"https://doi.org/10.1080/09603409.2023.2188681","url":null,"abstract":"Anodamine-based","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"22 1","pages":"101 - 109"},"PeriodicalIF":1.3,"publicationDate":"2023-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75970776","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 : 2023-03-03DOI: 10.1080/09603409.2023.2182587
K. Dawson, F. Duarte-Martinez, S. Gray, J. Nicholls, G. Gibson, J. Leggett, G. Tatlock
ABSTRACT Single crystal material, of CMSX-4® alloy composition, was cast and secondary orientation was controlled at the machining stage, to produce c-ring cross-section tubes with known crystallographic orientations. The c-ring tubes were coated with NaCl before being subject to loading up to 700MPa and heated for durations of up to 2 hrs at 550°C in flowing environments containing air and SO2. No cracking was observed in short term tests that were run in the absence of either NaCl, or SO2, indicating a symbiotic interaction is required to initiate cracking. Experiments confirm the presence of oxygen, chlorine and sulphur at the crack tips, formed along {001} crystallographic planes, however, they were distributed discretely, with several oxide and sulphide phases observed. In this work, we image, analyse and identify the phases formed during the cracking and corrosion of CMSX-4® superalloy and hypothesise on the complex chemical interactions that take place during crack initiation.
{"title":"Environmentally assisted cracking of a single crystal nickel-based superalloy","authors":"K. Dawson, F. Duarte-Martinez, S. Gray, J. Nicholls, G. Gibson, J. Leggett, G. Tatlock","doi":"10.1080/09603409.2023.2182587","DOIUrl":"https://doi.org/10.1080/09603409.2023.2182587","url":null,"abstract":"ABSTRACT Single crystal material, of CMSX-4® alloy composition, was cast and secondary orientation was controlled at the machining stage, to produce c-ring cross-section tubes with known crystallographic orientations. The c-ring tubes were coated with NaCl before being subject to loading up to 700MPa and heated for durations of up to 2 hrs at 550°C in flowing environments containing air and SO2. No cracking was observed in short term tests that were run in the absence of either NaCl, or SO2, indicating a symbiotic interaction is required to initiate cracking. Experiments confirm the presence of oxygen, chlorine and sulphur at the crack tips, formed along {001} crystallographic planes, however, they were distributed discretely, with several oxide and sulphide phases observed. In this work, we image, analyse and identify the phases formed during the cracking and corrosion of CMSX-4® superalloy and hypothesise on the complex chemical interactions that take place during crack initiation.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"1 1","pages":"296 - 307"},"PeriodicalIF":1.3,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74450159","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 : 2023-02-25DOI: 10.1080/09603409.2023.2177938
M. Taylor, J. Husband
ABSTRACT The results are presented on the oxidation behaviour of two chromia-forming steels, over the temperature range 800°C to 900°C, regions of premature localised breakaway oxidation were observed. SiO2 formation along emergent grain boundaries encapsulated smaller grains, acting as diffusion barriers to the replenishment of chromium from deeper in the alloy. Rapid depletion of chromium from these isolated grains continued with increasing time until the concentration was insufficient to maintain a protective Cr2O3 resulting in the localised chemical failure and formation of breakaway oxides. A finite difference model was used to demonstrate the effect of SiO2 formation. It was also found that the low concentration of silicon restricted the encapsulation process to only the smaller grains at the surface and protective oxidation was re-established underneath at the alloy surface. The predicted lifetime of components with wall thicknesses of 2 mm was calculated to be in excess of 30 years.
{"title":"Oxidation of SS304 and SS316 and the formation of diffusionally isolated regions leading to localised premature breakaway oxidation","authors":"M. Taylor, J. Husband","doi":"10.1080/09603409.2023.2177938","DOIUrl":"https://doi.org/10.1080/09603409.2023.2177938","url":null,"abstract":"ABSTRACT The results are presented on the oxidation behaviour of two chromia-forming steels, over the temperature range 800°C to 900°C, regions of premature localised breakaway oxidation were observed. SiO2 formation along emergent grain boundaries encapsulated smaller grains, acting as diffusion barriers to the replenishment of chromium from deeper in the alloy. Rapid depletion of chromium from these isolated grains continued with increasing time until the concentration was insufficient to maintain a protective Cr2O3 resulting in the localised chemical failure and formation of breakaway oxides. A finite difference model was used to demonstrate the effect of SiO2 formation. It was also found that the low concentration of silicon restricted the encapsulation process to only the smaller grains at the surface and protective oxidation was re-established underneath at the alloy surface. The predicted lifetime of components with wall thicknesses of 2 mm was calculated to be in excess of 30 years.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"138 1","pages":"318 - 330"},"PeriodicalIF":1.3,"publicationDate":"2023-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77567436","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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