Pub Date : 2022-11-07DOI: 10.1080/09500839.2022.2140216
Zhenyu Sun, Guili Liu, Juan Guo
ABSTRACT Vacancy defects and size variations are inevitable in the preparation of arsenene nanosheets, and the effect of size and random distribution of vacancy defects on the buckling properties of arsenene nanosheets is not negligible. Previous research methods, such as molecular dynamics, have limitations in terms of computational cost when investigating this aspect. In this paper, a model of arsenene nanosheets is developed based on the finite element method and the buckling properties of arsenene nanosheets are investigated under various operating conditions such as different sizes, different orientations and the presence of vacancy defects. The results show that the buckling performance of arsenene nanosheets is enhanced by smaller size. In contrast, the presence of vacancy defects leads to the destruction of the original structure of arsenene nanosheets, resulting in a decrease in their buckling properties. This study provides an important contribution to the investigation of the buckling properties of arsenene nanosheets.
{"title":"Effect of size and vacancy defects on buckling properties of arsenene nanosheets","authors":"Zhenyu Sun, Guili Liu, Juan Guo","doi":"10.1080/09500839.2022.2140216","DOIUrl":"https://doi.org/10.1080/09500839.2022.2140216","url":null,"abstract":"ABSTRACT Vacancy defects and size variations are inevitable in the preparation of arsenene nanosheets, and the effect of size and random distribution of vacancy defects on the buckling properties of arsenene nanosheets is not negligible. Previous research methods, such as molecular dynamics, have limitations in terms of computational cost when investigating this aspect. In this paper, a model of arsenene nanosheets is developed based on the finite element method and the buckling properties of arsenene nanosheets are investigated under various operating conditions such as different sizes, different orientations and the presence of vacancy defects. The results show that the buckling performance of arsenene nanosheets is enhanced by smaller size. In contrast, the presence of vacancy defects leads to the destruction of the original structure of arsenene nanosheets, resulting in a decrease in their buckling properties. This study provides an important contribution to the investigation of the buckling properties of arsenene nanosheets.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43087712","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 : 2022-10-20DOI: 10.1080/09500839.2022.2134938
T. Stasiak, M. Sow, M. Touzin, F. Béclin, C. Cordier
ABSTRACT This study aimed to prepare a composite of the high-entropy alloy from the Al-Cr-Fe-Mn-Mo system reinforced by in-situ formed carbides using powder metallurgy techniques. The alloyed powder was prepared by mechanical alloying in ball-mill devices from pure elemental powders with the addition of a process control agent, namely stearic acid. Then, the alloyed powder was consolidated by hot-press sintering. The structure and microstructure of powder and bulk samples were investigated. The mechanical properties of the bulk sample were evaluated. The investigations revealed two bcc phases in the mechanically alloyed powder. The powder annealing at 950°C triggered the phase transformations, which led to the formation of the multielement matrix bcc phase (a = 2.91 Å) reinforced by two carbides molybdenum-rich M6C (a = 11.15 Å) and chromium-rich M23C6 (a = 10.66 Å). A similar composite structure was present in the bulk sample. The investigations suggested that the primary carbon source for carbide formation was the process control agent – stearic acid. The produced bulk composite revealed promising mechanical properties, such as very high hardness up to 1223 ± 99 HV2 and Young’s modulus of 246 ± 10 GPa.
{"title":"Preparation and characterisation of the Al-Cr-Fe-Mn-Mo high-entropy alloy reinforced by in-situ formed carbides","authors":"T. Stasiak, M. Sow, M. Touzin, F. Béclin, C. Cordier","doi":"10.1080/09500839.2022.2134938","DOIUrl":"https://doi.org/10.1080/09500839.2022.2134938","url":null,"abstract":"ABSTRACT This study aimed to prepare a composite of the high-entropy alloy from the Al-Cr-Fe-Mn-Mo system reinforced by in-situ formed carbides using powder metallurgy techniques. The alloyed powder was prepared by mechanical alloying in ball-mill devices from pure elemental powders with the addition of a process control agent, namely stearic acid. Then, the alloyed powder was consolidated by hot-press sintering. The structure and microstructure of powder and bulk samples were investigated. The mechanical properties of the bulk sample were evaluated. The investigations revealed two bcc phases in the mechanically alloyed powder. The powder annealing at 950°C triggered the phase transformations, which led to the formation of the multielement matrix bcc phase (a = 2.91 Å) reinforced by two carbides molybdenum-rich M6C (a = 11.15 Å) and chromium-rich M23C6 (a = 10.66 Å). A similar composite structure was present in the bulk sample. The investigations suggested that the primary carbon source for carbide formation was the process control agent – stearic acid. The produced bulk composite revealed promising mechanical properties, such as very high hardness up to 1223 ± 99 HV2 and Young’s modulus of 246 ± 10 GPa.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47814075","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 : 2022-10-06DOI: 10.1080/09500839.2022.2129108
Girish Bojjawar, Satyam Suwas, Atul H. Chokshi
ABSTRACT
This study examines the deformation behaviour of Ni-Co microwires exhibiting high strengths and ductility, where the addition of Co is intended to decrease the stacking fault energy. A reduction in stacking fault energy is likely to retard the recovery processes, refine grain size and enhance strain hardening by dislocation interactions at twin boundaries. Microwires were drawn to a strain of 5.88, from annealed Ni-Co alloys with Co content varying from 30 to 60 wt%. Subsequent tensile testing revealed a simultaneous increase in strength and ductility with an increase in Co content. The enhanced strength is a consequence of the finer grain size with an increase in Co, and the larger ductility is related to a combination of greater strain hardening and a higher strain rate sensitivity with an increase in Co. The textured drawn Ni-Co wires exhibited higher strengths than those obtained by severe plastic deformation with comparable grain sizes.
{"title":"Influence of Co content on the simultaneous enhancement of strength and ductility in severely drawn textured Ni-Co microwires","authors":"Girish Bojjawar, Satyam Suwas, Atul H. Chokshi","doi":"10.1080/09500839.2022.2129108","DOIUrl":"https://doi.org/10.1080/09500839.2022.2129108","url":null,"abstract":"<p><b>ABSTRACT</b></p><p>This study examines the deformation behaviour of Ni-Co microwires exhibiting high strengths and ductility, where the addition of Co is intended to decrease the stacking fault energy. A reduction in stacking fault energy is likely to retard the recovery processes, refine grain size and enhance strain hardening by dislocation interactions at twin boundaries. Microwires were drawn to a strain of 5.88, from annealed Ni-Co alloys with Co content varying from 30 to 60 wt%. Subsequent tensile testing revealed a simultaneous increase in strength and ductility with an increase in Co content. The enhanced strength is a consequence of the finer grain size with an increase in Co, and the larger ductility is related to a combination of greater strain hardening and a higher strain rate sensitivity with an increase in Co. The textured drawn Ni-Co wires exhibited higher strengths than those obtained by severe plastic deformation with comparable grain sizes.</p>","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138520654","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 : 2022-10-06DOI: 10.1080/09500839.2022.2129110
Dawei Liu, Jiuxing Zhang, Lei Huang, Song Li, B. Nong, Ying Jin, Yafei Pan
ABSTRACT The high-temperature oxidation behaviour of SPS-prepared Mo and Mo–5Ta alloys are investigated under the temperature range 300–700°C for 0–120 min in static air condition. The oxidation weight gains of Mo and Mo–5Ta conform to parabolic law at different oxidation times of 500°C and all remain at low levels. At low temperature (≤ 500°C), the oxidation resistance improves with Ta addition. However, at 600°C and 700°C, the oxidation of Mo–5Ta increases and the weight gain is obvious. Compared with pure Mo, a continuous and dense oxide scale can be formed quickly on the surface of Mo–5Ta alloys during the oxidation process at 500°C, which improves the oxidation resistance of the alloys. The volatile MoO3 and generated Ta2O5 above 500°C cause more voids to form in the matrix, resulting in the deterioration of the oxidation resistance of the alloys.
{"title":"High-temperature oxidation behaviour of SPS-prepared Mo and Mo–5Ta alloys","authors":"Dawei Liu, Jiuxing Zhang, Lei Huang, Song Li, B. Nong, Ying Jin, Yafei Pan","doi":"10.1080/09500839.2022.2129110","DOIUrl":"https://doi.org/10.1080/09500839.2022.2129110","url":null,"abstract":"ABSTRACT The high-temperature oxidation behaviour of SPS-prepared Mo and Mo–5Ta alloys are investigated under the temperature range 300–700°C for 0–120 min in static air condition. The oxidation weight gains of Mo and Mo–5Ta conform to parabolic law at different oxidation times of 500°C and all remain at low levels. At low temperature (≤ 500°C), the oxidation resistance improves with Ta addition. However, at 600°C and 700°C, the oxidation of Mo–5Ta increases and the weight gain is obvious. Compared with pure Mo, a continuous and dense oxide scale can be formed quickly on the surface of Mo–5Ta alloys during the oxidation process at 500°C, which improves the oxidation resistance of the alloys. The volatile MoO3 and generated Ta2O5 above 500°C cause more voids to form in the matrix, resulting in the deterioration of the oxidation resistance of the alloys.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48784319","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 : 2022-10-03DOI: 10.1080/09500839.2022.2123113
J. Maity
ABSTRACT An analytical model is developed to explain the kinetics of grain growth in steel that takes into account all feasible prime phenomena; namely, surface energy reduction, precipitate pinning effect and solute drag effect. The shapes of matrix grains and the precipitates are assumed to be tetrakeidecahedron and spherical, respectively. A single solute and a single type of precipitate are further assumed to be responsible for the solute drag and the precipitate pinning, respectively. An explanation of drag energy is provided in terms of Gibbs free energy change for solute segregation that eventually merges to the well-known Langmuir–McLean relationship. The developed model is validated in view of the existing database in available literature. A new methodology of grain growth analysis is accordingly proposed on the basis of the conceptualised ‘effective migration coefficient’ of the system.
{"title":"An analytical model of grain growth considering the conjoint effects of precipitate pinning and solute drag in steel","authors":"J. Maity","doi":"10.1080/09500839.2022.2123113","DOIUrl":"https://doi.org/10.1080/09500839.2022.2123113","url":null,"abstract":"ABSTRACT An analytical model is developed to explain the kinetics of grain growth in steel that takes into account all feasible prime phenomena; namely, surface energy reduction, precipitate pinning effect and solute drag effect. The shapes of matrix grains and the precipitates are assumed to be tetrakeidecahedron and spherical, respectively. A single solute and a single type of precipitate are further assumed to be responsible for the solute drag and the precipitate pinning, respectively. An explanation of drag energy is provided in terms of Gibbs free energy change for solute segregation that eventually merges to the well-known Langmuir–McLean relationship. The developed model is validated in view of the existing database in available literature. A new methodology of grain growth analysis is accordingly proposed on the basis of the conceptualised ‘effective migration coefficient’ of the system.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46317395","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 : 2022-10-03DOI: 10.1080/09500839.2022.2129109
Jianlin Li, Jinke Han, Fance Song, Haoyu Zhang, Ge Zhou, Lijia Chen, Xue Cao
ABSTRACT High-entropy alloys (HEAs) were studied via hot compression experiments using a Gleeble-3800 thermal simulation tester. The hot deformation behaviour of an AlFeCoNiMo0.2 HEA and the physical significance of the associated parameters were analyzed according to the Prasad, Gegel, Malas, and Murty instability criteria. Processing maps of different instability criteria under different conditions were constructed. The domain corresponding to a temperature range of 1070°C–1150°C with a strain rate range of 0.001–0.1 s−1 and average power dissipation rates of >40% did not feature flow instability; thus, this domain is appropriate for the AlFeCoNiMo0.2 HEA deformation process. Through microstructure analysis, it was determined that the deformation mechanism in the optimal forming region is dynamic recrystallization.
{"title":"A comparative study of flow instability criteria in the processing map of AlFeCoNiMo0.2 high-entropy alloys","authors":"Jianlin Li, Jinke Han, Fance Song, Haoyu Zhang, Ge Zhou, Lijia Chen, Xue Cao","doi":"10.1080/09500839.2022.2129109","DOIUrl":"https://doi.org/10.1080/09500839.2022.2129109","url":null,"abstract":"ABSTRACT High-entropy alloys (HEAs) were studied via hot compression experiments using a Gleeble-3800 thermal simulation tester. The hot deformation behaviour of an AlFeCoNiMo0.2 HEA and the physical significance of the associated parameters were analyzed according to the Prasad, Gegel, Malas, and Murty instability criteria. Processing maps of different instability criteria under different conditions were constructed. The domain corresponding to a temperature range of 1070°C–1150°C with a strain rate range of 0.001–0.1 s−1 and average power dissipation rates of >40% did not feature flow instability; thus, this domain is appropriate for the AlFeCoNiMo0.2 HEA deformation process. Through microstructure analysis, it was determined that the deformation mechanism in the optimal forming region is dynamic recrystallization.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44660630","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 : 2022-09-29DOI: 10.1080/09500839.2022.2126535
Katsutoshi Takashima, R. Han, K. Yokoyama, Y. Funakawa
ABSTRACT The continuousness of the interactions between hydrogen and plastic deformation of an ultra-high strength steel sheet consisting of ferrite and nanometer-sized precipitates has been investigated by tensile tests after or during cathodic hydrogen charging. In the tensile test in the air after hydrogen pre-charging, a hydrogen thermal desorption analysis shows that the amount of hydrogen desorbed decreases with increasing applied tensile strain from room temperature to 50 °C, but increases in the high temperature region. Upon tensile straining to 0.06, no hydrogen is desorbed in the low temperature region, and the change in desorption behaviour when strain exceeds 0.06 is negligible. This suggests that substantial interactions between hydrogen and plastic deformation in the test with hydrogen pre-charging occur only in the early stages of deformation. In contrast, in the tensile test during hydrogen charging, the hydrogen desorption which begins from room temperature continues even upon tensile straining to 0.06, suggesting continuous interactions, and a unique dislocation structure resembling sub-grain boundaries is observed. Upon aging at room temperature after tensile straining to 0.06 during hydrogen charging, all hydrogen desorption lower than 100 °C shifts to the high temperature region, but the recovery of elongation is not necessarily complete. When tensile strain is applied during hydrogen charging, continuous interactions presumably induce anomalous damage, thereby enhancing the degradation of ductility. The results of the present study strongly support the conclusion that the continuousness of the dynamic interactions between hydrogen and plastic deformation plays essential roles in hydrogen embrittlement of ferritic steel.
{"title":"Continuousness of interactions between hydrogen and plastic deformation of ultra-high strength steel sheet consisting of ferrite and nanometer-sized precipitates","authors":"Katsutoshi Takashima, R. Han, K. Yokoyama, Y. Funakawa","doi":"10.1080/09500839.2022.2126535","DOIUrl":"https://doi.org/10.1080/09500839.2022.2126535","url":null,"abstract":"ABSTRACT The continuousness of the interactions between hydrogen and plastic deformation of an ultra-high strength steel sheet consisting of ferrite and nanometer-sized precipitates has been investigated by tensile tests after or during cathodic hydrogen charging. In the tensile test in the air after hydrogen pre-charging, a hydrogen thermal desorption analysis shows that the amount of hydrogen desorbed decreases with increasing applied tensile strain from room temperature to 50 °C, but increases in the high temperature region. Upon tensile straining to 0.06, no hydrogen is desorbed in the low temperature region, and the change in desorption behaviour when strain exceeds 0.06 is negligible. This suggests that substantial interactions between hydrogen and plastic deformation in the test with hydrogen pre-charging occur only in the early stages of deformation. In contrast, in the tensile test during hydrogen charging, the hydrogen desorption which begins from room temperature continues even upon tensile straining to 0.06, suggesting continuous interactions, and a unique dislocation structure resembling sub-grain boundaries is observed. Upon aging at room temperature after tensile straining to 0.06 during hydrogen charging, all hydrogen desorption lower than 100 °C shifts to the high temperature region, but the recovery of elongation is not necessarily complete. When tensile strain is applied during hydrogen charging, continuous interactions presumably induce anomalous damage, thereby enhancing the degradation of ductility. The results of the present study strongly support the conclusion that the continuousness of the dynamic interactions between hydrogen and plastic deformation plays essential roles in hydrogen embrittlement of ferritic steel.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42138427","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 : 2022-09-02DOI: 10.1080/09500839.2022.2120644
Bejjipurapu Akhil, A. Bajpai, K. Biswas
ABSTRACT In the present study, the intelligent addition of Re and Al to TiZrHf equiatomic ternary alloy resulted in a new single-phase Ti30Zr30Hf30Re5Al5 HCP high entropy alloy. The XRD analyses show that the TiZrHfRex alloys have a single-phase HCP structure until x = 5 at.%. Subsequently, the TiZrHfRe5 retains its single-phase HCP microstructure with the addition of Al upto 5 at.%, leading to a new quinary TiZrHfRe5Al5 HCP HEA. Microstructural investigations using SEM revealed the formation of compositionally homogeneous single-phase HCP solid solution for TiZrHf, TiZrHfRe5 and TiZrHfRe5Al5 alloys. Vicker's microindentation measurements revealed that adding Re, followed by Al, increases the hardness of the TiZrHf ternary alloy from 7.85 0.37–8.35 0.42 GPa. In a nutshell, a novel quinary HCP alloy was developed based on transition metals, allowing HCP HEA compositional space to expand beyond rare-earth (RE) based HEAs.
{"title":"Microstructure and mechanical properties of the new TiZrHfReAl HCP high entropy alloy","authors":"Bejjipurapu Akhil, A. Bajpai, K. Biswas","doi":"10.1080/09500839.2022.2120644","DOIUrl":"https://doi.org/10.1080/09500839.2022.2120644","url":null,"abstract":"ABSTRACT In the present study, the intelligent addition of Re and Al to TiZrHf equiatomic ternary alloy resulted in a new single-phase Ti30Zr30Hf30Re5Al5 HCP high entropy alloy. The XRD analyses show that the TiZrHfRex alloys have a single-phase HCP structure until x = 5 at.%. Subsequently, the TiZrHfRe5 retains its single-phase HCP microstructure with the addition of Al upto 5 at.%, leading to a new quinary TiZrHfRe5Al5 HCP HEA. Microstructural investigations using SEM revealed the formation of compositionally homogeneous single-phase HCP solid solution for TiZrHf, TiZrHfRe5 and TiZrHfRe5Al5 alloys. Vicker's microindentation measurements revealed that adding Re, followed by Al, increases the hardness of the TiZrHf ternary alloy from 7.85 0.37–8.35 0.42 GPa. In a nutshell, a novel quinary HCP alloy was developed based on transition metals, allowing HCP HEA compositional space to expand beyond rare-earth (RE) based HEAs.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41333070","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 : 2022-09-02DOI: 10.1080/09500839.2022.2118386
Y. Mei
ABSTRACT This paper gives for the first time a complete equation to analyze the temperature dependence (or thermal variation) of spin-Hamiltonian parameter from low to high temperatures for transition metal and rare-earth ions in crystals. This equation includes not only the dynamic effect (only considered in previous papers) caused by electron–phonon interaction but also the static effect owing to lattice thermal expansion. Based on the complete equation, the thermal variations of zero-field splitting b4 0 from low to high temperatures for cubic Eu2+ and Gd3+ centers in CdF2 crystal are studied. The contributions due to static effect are estimated from the pressure dependence of zero-field splitting b4 0. The static parameters B (charactering the static effect) and the electron–phonon coupling parameters K (charactering the dynamic effect) for both systems are determined and the coefficients (B + K) in the complete equation are obtained. The results are discussed.
{"title":"A complete study on the temperature dependences of zero-field splitting b4 0 for Eu2+ and Gd3+ ions in CdF2 crystal","authors":"Y. Mei","doi":"10.1080/09500839.2022.2118386","DOIUrl":"https://doi.org/10.1080/09500839.2022.2118386","url":null,"abstract":"ABSTRACT This paper gives for the first time a complete equation to analyze the temperature dependence (or thermal variation) of spin-Hamiltonian parameter from low to high temperatures for transition metal and rare-earth ions in crystals. This equation includes not only the dynamic effect (only considered in previous papers) caused by electron–phonon interaction but also the static effect owing to lattice thermal expansion. Based on the complete equation, the thermal variations of zero-field splitting b4 0 from low to high temperatures for cubic Eu2+ and Gd3+ centers in CdF2 crystal are studied. The contributions due to static effect are estimated from the pressure dependence of zero-field splitting b4 0. The static parameters B (charactering the static effect) and the electron–phonon coupling parameters K (charactering the dynamic effect) for both systems are determined and the coefficients (B + K) in the complete equation are obtained. The results are discussed.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48700283","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 : 2022-09-02DOI: 10.1080/09500839.2022.2121866
C. Singh, S. Singh, J. Jain
ABSTRACT The hydrogen evolution process in the as-cast Mg-0.6Ca alloy was investigated using real-time optical imaging of the corroding surface. It was revealed that hydrogen evolved as large stable bubbles and continuous streams of tiny bubbles because of high localised current density. To the best of the author’s knowledge, this is the first attempt to characterise the hydrogen evolution behaviour of Mg-Ca binary alloy employing a mechanistic model based on real-time imaging.
{"title":"Elucidating the role of micro-galvanic coupling between eutectic α-Mg lamellas and α-Mg matrix on the hydrogen evolution behaviour of Mg-0.6Ca binary alloy using real-time imaging","authors":"C. Singh, S. Singh, J. Jain","doi":"10.1080/09500839.2022.2121866","DOIUrl":"https://doi.org/10.1080/09500839.2022.2121866","url":null,"abstract":"ABSTRACT The hydrogen evolution process in the as-cast Mg-0.6Ca alloy was investigated using real-time optical imaging of the corroding surface. It was revealed that hydrogen evolved as large stable bubbles and continuous streams of tiny bubbles because of high localised current density. To the best of the author’s knowledge, this is the first attempt to characterise the hydrogen evolution behaviour of Mg-Ca binary alloy employing a mechanistic model based on real-time imaging.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42352419","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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