Christian Hempel, M. Mandel, C. Schimpf, L. Krüger
The hot corrosion behavior of plasma transferred arc (PTA) welded René 41 in NaCl, NaVO3, Na2SO4, and a salt mixture of 87.5 wt% Na2SO4 + 5 wt% NaCl + 7.5 wt% NaVO3 was investigated at 600°C. The single‐salt experiments were carried out to identify specific corrosion characteristics and to provide insights into and, thus, an understanding of the corresponding corrosion processes. NaVO3 and NaCl showed strong corrosive effects, while Na2SO4 proved less corrosive. Long‐term experiments were carried out to simulate real machine operating conditions. After cyclic studies with repeated changes in temperature, the deep and local corrosive attack became apparent, which is characteristic for low‐temperature hot corrosion.
{"title":"Long‐term low‐temperature hot corrosion of PTA welded René 41 superalloy under marine‐like conditions","authors":"Christian Hempel, M. Mandel, C. Schimpf, L. Krüger","doi":"10.1002/maco.202213053","DOIUrl":"https://doi.org/10.1002/maco.202213053","url":null,"abstract":"The hot corrosion behavior of plasma transferred arc (PTA) welded René 41 in NaCl, NaVO3, Na2SO4, and a salt mixture of 87.5 wt% Na2SO4 + 5 wt% NaCl + 7.5 wt% NaVO3 was investigated at 600°C. The single‐salt experiments were carried out to identify specific corrosion characteristics and to provide insights into and, thus, an understanding of the corresponding corrosion processes. NaVO3 and NaCl showed strong corrosive effects, while Na2SO4 proved less corrosive. Long‐term experiments were carried out to simulate real machine operating conditions. After cyclic studies with repeated changes in temperature, the deep and local corrosive attack became apparent, which is characteristic for low‐temperature hot corrosion.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"35 1","pages":"1369 - 1382"},"PeriodicalIF":0.0,"publicationDate":"2022-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87687047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A combination of scanning microelectrochemical techniques along with the conventional electrochemical approaches is explored to attain insight information on the localized corrosion on the newly developed lean duplex stainless steel (LDSS) alloys. The obtained results from dynamic electrochemical impedance spectroscopic (DEIS) tests explained the beneficial role of different alloying elements on the passive and transpassive regions of the investigated LDSS alloys in a 3.5% NaCl solution. The scanning vibrating electrode technique (SVET) was effective in examining the anodic and cathodic regions on the corroding LDSS, whereas the scanning electrochemical microscopy (SECM) technique was employed to explore the localized corrosion sites on LDSS in NaCl solution. The acquired SVET results revealed a reduction in the susceptibility of the newly developed alloys to localized corrosion concerning their composition, accounting for the enhanced corrosion resistance. The obtained result from conventional and scanning microelectrochemical techniques obviously revealed the LDSS alloy with the composition of Fe–16Cr–2Ni–2Mn–1Mo exhibited higher localized corrosion resistance in NaCl solution.
{"title":"Dynamic and localized microelectrochemical approaches to evaluate the corrosion resistance of newly developed lean duplex stainless steel alloys","authors":"Arumugam Madhan Kumar, I. Toor","doi":"10.1002/maco.202213174","DOIUrl":"https://doi.org/10.1002/maco.202213174","url":null,"abstract":"A combination of scanning microelectrochemical techniques along with the conventional electrochemical approaches is explored to attain insight information on the localized corrosion on the newly developed lean duplex stainless steel (LDSS) alloys. The obtained results from dynamic electrochemical impedance spectroscopic (DEIS) tests explained the beneficial role of different alloying elements on the passive and transpassive regions of the investigated LDSS alloys in a 3.5% NaCl solution. The scanning vibrating electrode technique (SVET) was effective in examining the anodic and cathodic regions on the corroding LDSS, whereas the scanning electrochemical microscopy (SECM) technique was employed to explore the localized corrosion sites on LDSS in NaCl solution. The acquired SVET results revealed a reduction in the susceptibility of the newly developed alloys to localized corrosion concerning their composition, accounting for the enhanced corrosion resistance. The obtained result from conventional and scanning microelectrochemical techniques obviously revealed the LDSS alloy with the composition of Fe–16Cr–2Ni–2Mn–1Mo exhibited higher localized corrosion resistance in NaCl solution.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"14 1","pages":"1687 - 1700"},"PeriodicalIF":0.0,"publicationDate":"2022-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90666169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mechanical and corrosion behavior of high‐strength, high‐zinc (>7 wt%) containing 7068 aluminum alloy is investigated after employing different retrogression and reaging (RRA) treatments. The effect of preaging conditions on the distribution of copper, zinc, and magnesium, the volume fraction of η′ phase, and the width of precipitate free zones (PFZ) have been investigated. Microstructural and compositional features characterized by scanning electron microscope‐energy dispersive spectroscopy, scanning transmission electron microscope, and differential scanning calorimetry are correlated with hardness and corrosion performance. The localized attack is manifested in the dissolution of second phase precipitates which occurs from selective leaching of magnesium and aluminum. A combination of two opposite effects, that is, the presence of nobler, high‐copper grain boundary precipitates and microgalvanic effect of PFZ along with the distribution of alloying elements, that is, Cu, Zn, and Mg govern the electrochemical behavior of RRA‐treated 7068 alloy. Optimum preaging and RRA conditions are identified for this high‐zinc 7xxx series alloy.
{"title":"Effect of preaging temperature on microstructure evolution, mechanical and corrosion behavior of RRA‐treated high‐zinc 7068 alloy","authors":"Ankur Kumar, G. Chaudhari, S. Nath","doi":"10.1002/maco.202213196","DOIUrl":"https://doi.org/10.1002/maco.202213196","url":null,"abstract":"Mechanical and corrosion behavior of high‐strength, high‐zinc (>7 wt%) containing 7068 aluminum alloy is investigated after employing different retrogression and reaging (RRA) treatments. The effect of preaging conditions on the distribution of copper, zinc, and magnesium, the volume fraction of η′ phase, and the width of precipitate free zones (PFZ) have been investigated. Microstructural and compositional features characterized by scanning electron microscope‐energy dispersive spectroscopy, scanning transmission electron microscope, and differential scanning calorimetry are correlated with hardness and corrosion performance. The localized attack is manifested in the dissolution of second phase precipitates which occurs from selective leaching of magnesium and aluminum. A combination of two opposite effects, that is, the presence of nobler, high‐copper grain boundary precipitates and microgalvanic effect of PFZ along with the distribution of alloying elements, that is, Cu, Zn, and Mg govern the electrochemical behavior of RRA‐treated 7068 alloy. Optimum preaging and RRA conditions are identified for this high‐zinc 7xxx series alloy.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"6 1","pages":"1586 - 1603"},"PeriodicalIF":0.0,"publicationDate":"2022-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87516644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Waterborne anticorrosion coatings have aroused tremendous attention in the metal protection field due to their environmentally friendly properties. However, the limited barrier performance and poor resistance to corrosive species severely impede its practical applications. Herein, tannic acid‐copper metal‐organic framework (TA‐Cu) was first synthesized via oxidative coordination and then assembled with graphene oxide to obtain TA‐Cu‐decorated graphene oxide (TAG), which was utilized to improve the anticorrosion performance of waterborne epoxy (WEP) coatings. Electrochemical measurements demonstrated that the impermeability of WEP has been significantly enhanced with the incorporation of TAG. Meanwhile, local electrochemical impedance spectroscopy tests indicated that the corrosion reaction at defected region can be effectively suppressed, presenting an active anticorrosion function. The protection mechanisms are attributed to (1) TA‐Cu contributed to the dispersion of graphene oxide in WEP and impeded the intrusion of aggressive ions and (2) the coordination and adsorption of TA on steel inhibited the redox process and corrosion extension.
{"title":"Tannic acid‐copper metal‐organic frameworks decorated graphene oxide for reinforcement of the corrosion protection of waterborne epoxy coatings","authors":"Li Cheng, Peimin Hou, Chengbao Liu","doi":"10.1002/maco.202213189","DOIUrl":"https://doi.org/10.1002/maco.202213189","url":null,"abstract":"Waterborne anticorrosion coatings have aroused tremendous attention in the metal protection field due to their environmentally friendly properties. However, the limited barrier performance and poor resistance to corrosive species severely impede its practical applications. Herein, tannic acid‐copper metal‐organic framework (TA‐Cu) was first synthesized via oxidative coordination and then assembled with graphene oxide to obtain TA‐Cu‐decorated graphene oxide (TAG), which was utilized to improve the anticorrosion performance of waterborne epoxy (WEP) coatings. Electrochemical measurements demonstrated that the impermeability of WEP has been significantly enhanced with the incorporation of TAG. Meanwhile, local electrochemical impedance spectroscopy tests indicated that the corrosion reaction at defected region can be effectively suppressed, presenting an active anticorrosion function. The protection mechanisms are attributed to (1) TA‐Cu contributed to the dispersion of graphene oxide in WEP and impeded the intrusion of aggressive ions and (2) the coordination and adsorption of TA on steel inhibited the redox process and corrosion extension.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"13 1","pages":"1666 - 1675"},"PeriodicalIF":0.0,"publicationDate":"2022-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74586398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Masthead: Materials and Corrosion. 5/2022","authors":"","doi":"10.1002/maco.202270052","DOIUrl":"https://doi.org/10.1002/maco.202270052","url":null,"abstract":"","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86709006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present work investigates the influence of Ni content on the microstructure evolution of Al0.5CoCrFeNix high‐entropy alloys followed by the study on their corrosion behavior in acid and alkaline solutions, respectively. The microscopic characterization demonstrates that the transformation from a BCC single‐phase to a triple‐phase (BCC + FCC + B2) structure occurs with the increase of Ni content. The corrosion behavior of Al0.5CoCrFeNix high‐entropy alloys was evaluated by electrochemical measurements coupled with morphology analysis. It is found that the corrosion on Al0.5CoCrFeNi0 high‐entropy alloy in both acid and alkaline media is uniform due to its homogeneous microstructure. In contrast, the increase of Ni content leads to the formation of Al, Ni enriched B2 phase with lower Volta potential, causing the respective occurrence of selective dissolution in acid and preferential oxidation in alkaline on the Al0.5CoCrFeNi0.2, Al0.5CoCrFeNi0.6, and Al0.5CoCrFeNi0.8 high‐entropy alloys.
{"title":"Effects of Ni content on the corrosion behavior of Al0.5CoCrFeNix high entropy alloys in acid and alkaline media","authors":"Qi Dong, Wenchao Jia, Zequn Zhang, Dingxin Zhang, Junsheng Wu, Bowei Zhang","doi":"10.1002/maco.202112851","DOIUrl":"https://doi.org/10.1002/maco.202112851","url":null,"abstract":"The present work investigates the influence of Ni content on the microstructure evolution of Al0.5CoCrFeNix high‐entropy alloys followed by the study on their corrosion behavior in acid and alkaline solutions, respectively. The microscopic characterization demonstrates that the transformation from a BCC single‐phase to a triple‐phase (BCC + FCC + B2) structure occurs with the increase of Ni content. The corrosion behavior of Al0.5CoCrFeNix high‐entropy alloys was evaluated by electrochemical measurements coupled with morphology analysis. It is found that the corrosion on Al0.5CoCrFeNi0 high‐entropy alloy in both acid and alkaline media is uniform due to its homogeneous microstructure. In contrast, the increase of Ni content leads to the formation of Al, Ni enriched B2 phase with lower Volta potential, causing the respective occurrence of selective dissolution in acid and preferential oxidation in alkaline on the Al0.5CoCrFeNi0.2, Al0.5CoCrFeNi0.6, and Al0.5CoCrFeNi0.8 high‐entropy alloys.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"1 1","pages":"1274 - 1285"},"PeriodicalIF":0.0,"publicationDate":"2022-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77594978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thin coatings AlN, AlZrN, and AlCrN were deposited by pulsed magnetron sputtering. The high‐speed steel Т1, structural alloy steel 5140, and structural carbon steel 1017 were used as substrates. The magnetron current, nitrogen content in the gas mixture, and bias voltage on the substrate were changed to obtain nanostructured and amorphous layers of coatings with different elemental compositions. The voltammetry and impedance spectroscopy were performed on the coated samples in 3% NaCl solution. The corrosion behavior of the coatings was characterized by the corrosion current density icorr, the polarization resistance Rp (at the corrosion potential), the ratios icorr,s/icorr, and Rp/Rp,s, where subscript s refers to the substrate. It was shown that the coatings under study (except AlN) are electrochemically active, and the corrosion processes occur not only on the substrate in the coating discontinuity but on the coating surface as well. The coatings AlN/T1, AlZrN/5140, AlCrN/T1, and AlCrN/5140 with icorr ~ 10−7 A cm−2 are found to be the most corrosion‐resistant in 3% NaCl. The paper discusses factors affecting the corrosion behavior of the investigated coatings.
采用脉冲磁控溅射法制备了AlN、AlZrN和AlCrN薄膜。采用高速钢Т1、结构合金钢5140和结构碳钢1017作为衬底。通过改变磁控管电流、混合气体中的氮含量和衬底上的偏置电压，可以获得不同元素组成的纳米结构和非晶态涂层。对包被样品在3% NaCl溶液中进行伏安法和阻抗谱分析。涂层的腐蚀行为由腐蚀电流密度icorr、极化电阻Rp(腐蚀电位处)、比值icorr,s/icorr和Rp/Rp,s表征，其中下标s为基材。结果表明，除AlN外，所研究的涂层均具有电化学活性，腐蚀过程不仅发生在涂层不连续的基体上，也发生在涂层表面。结果表明，icorr为10−7 A cm−2的AlN/T1、AlZrN/5140、AlCrN/T1和AlCrN/5140涂层在3% NaCl中耐腐蚀性能最好。本文讨论了影响所研究涂层腐蚀行为的因素。
{"title":"Effect of structure, phase, and elemental composition of AlN, CrAlN, and ZrAlN coatings on their electrochemical behavior in 3% NaCl solution","authors":"A. Kameneva, V. Kichigin, N. Bublik","doi":"10.1002/maco.202213073","DOIUrl":"https://doi.org/10.1002/maco.202213073","url":null,"abstract":"Thin coatings AlN, AlZrN, and AlCrN were deposited by pulsed magnetron sputtering. The high‐speed steel Т1, structural alloy steel 5140, and structural carbon steel 1017 were used as substrates. The magnetron current, nitrogen content in the gas mixture, and bias voltage on the substrate were changed to obtain nanostructured and amorphous layers of coatings with different elemental compositions. The voltammetry and impedance spectroscopy were performed on the coated samples in 3% NaCl solution. The corrosion behavior of the coatings was characterized by the corrosion current density icorr, the polarization resistance Rp (at the corrosion potential), the ratios icorr,s/icorr, and Rp/Rp,s, where subscript s refers to the substrate. It was shown that the coatings under study (except AlN) are electrochemically active, and the corrosion processes occur not only on the substrate in the coating discontinuity but on the coating surface as well. The coatings AlN/T1, AlZrN/5140, AlCrN/T1, and AlCrN/5140 with icorr ~ 10−7 A cm−2 are found to be the most corrosion‐resistant in 3% NaCl. The paper discusses factors affecting the corrosion behavior of the investigated coatings.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"30 1","pages":"1308 - 1317"},"PeriodicalIF":0.0,"publicationDate":"2022-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84466683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present work, the Cr–AlSi12 composite coatings were successfully synthesized on the Ti–6Al–4V alloy substrate by using the mechanical alloying method. The effects of raw Cr particle size, milling duration, and annealing treatment on the preparation of the coatings were investigated. The as‐prepared coatings consisted of the inner coating layer with coarse Cr particles and the outer coating layer with refined and highly homogenized structure. The annealing treatment could promote element diffusion and alloying; it was favorable to the densification and oxidation resistance of the coatings. There is a highly densified alloyed layer in the outer coating. The annealed coating showed excellent friction and wear resistance. After the oxidation process, the annealed coating showed the best high‐temperature oxidation resistance. The oxidized annealed coating exhibited four layers, which included the thin Al2O3 oxide film, the homogenized alloyed layer, the composite layer consisted of Al2O3 and coarse Cr particles surrounded by alloyed layer, and the Al3Ti diffusion layer. This was favorable to the improvement of high‐temperature oxidation resistance. The oxidation process of the annealed coating was elaborated.
{"title":"High‐temperature corrosion of mechanically alloyed Cr–AlSi12 composite coatings on Ti–6Al–4V alloy substrate","authors":"Jiangzhong Jiang, Xiaomei Feng, Yifu Shen","doi":"10.1002/maco.202113008","DOIUrl":"https://doi.org/10.1002/maco.202113008","url":null,"abstract":"In the present work, the Cr–AlSi12 composite coatings were successfully synthesized on the Ti–6Al–4V alloy substrate by using the mechanical alloying method. The effects of raw Cr particle size, milling duration, and annealing treatment on the preparation of the coatings were investigated. The as‐prepared coatings consisted of the inner coating layer with coarse Cr particles and the outer coating layer with refined and highly homogenized structure. The annealing treatment could promote element diffusion and alloying; it was favorable to the densification and oxidation resistance of the coatings. There is a highly densified alloyed layer in the outer coating. The annealed coating showed excellent friction and wear resistance. After the oxidation process, the annealed coating showed the best high‐temperature oxidation resistance. The oxidized annealed coating exhibited four layers, which included the thin Al2O3 oxide film, the homogenized alloyed layer, the composite layer consisted of Al2O3 and coarse Cr particles surrounded by alloyed layer, and the Al3Ti diffusion layer. This was favorable to the improvement of high‐temperature oxidation resistance. The oxidation process of the annealed coating was elaborated.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"51 1","pages":"1248 - 1264"},"PeriodicalIF":0.0,"publicationDate":"2022-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88440149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. N. Dobrotvorskaia, M. A. Dobrotvorskii, É. P. Shevyakova, M. A. Simanov
This study investigates the damage, microstructure, and mechanical evolution of service‐exposed HP40NbTi radiant tubes of a steam reformer furnace. Tube failure was reported after 6‐year of working at 525°C–830°C in the form of visible longitudinal and transverse cracks. The microstructure was evaluated using optical and scanning electron microscopy equipped with energy‐dispersive X‐ray spectrum analysis. The carbide phase transformation was determined by the method based on the matrix dissolution technique and X‐ray diffraction. The results of this study showed that the primary cause of the longitudinal crack formation is the local overheating and the oxidation of the dendritic grain boundaries. The M7C3 carbide transforms completely into the metastable M23C6 phase during high‐temperature service. Metallographic examinations revealed the shrinkage cavities and creep voids that are nucleated on both Cr‐ and Nb‐carbides. The continuous oxide layers of Cr2O3 and SiO2 formed near the inner and outer tube surfaces and the matrix's chemical composition near the outer tube surface was found to be depleted of Cr and C. Mechanical properties are irregular across the samples. A little margin of safety is noted, while the complete ductility dip is detected at room temperature. The root cause analysis of the failure under investigation showed that the tube failed due to the creep.
{"title":"Failure cause assessment of steam reformer radiant tube after long‐term service","authors":"A. N. Dobrotvorskaia, M. A. Dobrotvorskii, É. P. Shevyakova, M. A. Simanov","doi":"10.1002/maco.202213068","DOIUrl":"https://doi.org/10.1002/maco.202213068","url":null,"abstract":"This study investigates the damage, microstructure, and mechanical evolution of service‐exposed HP40NbTi radiant tubes of a steam reformer furnace. Tube failure was reported after 6‐year of working at 525°C–830°C in the form of visible longitudinal and transverse cracks. The microstructure was evaluated using optical and scanning electron microscopy equipped with energy‐dispersive X‐ray spectrum analysis. The carbide phase transformation was determined by the method based on the matrix dissolution technique and X‐ray diffraction. The results of this study showed that the primary cause of the longitudinal crack formation is the local overheating and the oxidation of the dendritic grain boundaries. The M7C3 carbide transforms completely into the metastable M23C6 phase during high‐temperature service. Metallographic examinations revealed the shrinkage cavities and creep voids that are nucleated on both Cr‐ and Nb‐carbides. The continuous oxide layers of Cr2O3 and SiO2 formed near the inner and outer tube surfaces and the matrix's chemical composition near the outer tube surface was found to be depleted of Cr and C. Mechanical properties are irregular across the samples. A little margin of safety is noted, while the complete ductility dip is detected at room temperature. The root cause analysis of the failure under investigation showed that the tube failed due to the creep.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"6 1","pages":"1265 - 1273"},"PeriodicalIF":0.0,"publicationDate":"2022-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80476283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaodan Lv, Shuhui Liu, H. Xie, Qingming Cao, Chengdong Zhang, Fanwei Chen, Bin Liu
AMg61 (Al‐6.2% Mg), a novel form of high‐strength, high‐magnesium‐content aluminum alloy, has been developed for specific maritime engineering in recent years, while its corrosion behavior in seawater is still unknown. Therefore, the corrosion behavior of AMg61 in the simulated seawater was investigated herein, using a weight‐loss test and different electrochemical measurements. In addition, corrosion morphology and chemical contents were characterized by metallography, scanning electron microscopy, and energy‐dispersive spectroscopy. The results demonstrated that intergranular corrosion and microcracks developed first in the second phase of AMg61, followed by pitting corrosion. The matrix of AMg61, on the other hand, exhibited a uniform and exfoliation corrosion. The corrosion rate gradually decreased over time.
{"title":"Corrosion behavior of a newly developed high strength aluminum alloy with high magnesium content under simulated seawater environment","authors":"Xiaodan Lv, Shuhui Liu, H. Xie, Qingming Cao, Chengdong Zhang, Fanwei Chen, Bin Liu","doi":"10.1002/maco.202213065","DOIUrl":"https://doi.org/10.1002/maco.202213065","url":null,"abstract":"AMg61 (Al‐6.2% Mg), a novel form of high‐strength, high‐magnesium‐content aluminum alloy, has been developed for specific maritime engineering in recent years, while its corrosion behavior in seawater is still unknown. Therefore, the corrosion behavior of AMg61 in the simulated seawater was investigated herein, using a weight‐loss test and different electrochemical measurements. In addition, corrosion morphology and chemical contents were characterized by metallography, scanning electron microscopy, and energy‐dispersive spectroscopy. The results demonstrated that intergranular corrosion and microcracks developed first in the second phase of AMg61, followed by pitting corrosion. The matrix of AMg61, on the other hand, exhibited a uniform and exfoliation corrosion. The corrosion rate gradually decreased over time.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"5 1","pages":"1318 - 1329"},"PeriodicalIF":0.0,"publicationDate":"2022-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75325483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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