Pub Date : 2024-12-31DOI: 10.1016/j.scriptamat.2024.116528
Min-Seok Kim
This study investigates the control of surface inverse segregation in Al−4.5Mg alloy strips produced using the industrial twin-roll casting (TRC) process. The effects of the casting speed, melt temperature, interfacial heat transfer coefficient, and melt pool height on the solidification behavior were evaluated using simulations. The findings revealed that minimizing the shrinkage deformation of the solidifying shell near the kiss point (KP) is critical for controlling inverse segregation. The total thickness of the solidifying shell was reduced by shifting the KP toward the roll nip direction, enhancing the strip quality. By applying the strategy of KP adjustments to TRC conditions, we successfully reduced the strip thickness and produced high-quality strips without an inverse segregation layer on the strip surface.
{"title":"Control of surface inverse segregation in Al–4.5Mg strips produced by industrial twin-roll casting process","authors":"Min-Seok Kim","doi":"10.1016/j.scriptamat.2024.116528","DOIUrl":"10.1016/j.scriptamat.2024.116528","url":null,"abstract":"<div><div>This study investigates the control of surface inverse segregation in Al−4.5Mg alloy strips produced using the industrial twin-roll casting (TRC) process. The effects of the casting speed, melt temperature, interfacial heat transfer coefficient, and melt pool height on the solidification behavior were evaluated using simulations. The findings revealed that minimizing the shrinkage deformation of the solidifying shell near the kiss point (KP) is critical for controlling inverse segregation. The total thickness of the solidifying shell was reduced by shifting the KP toward the roll nip direction, enhancing the strip quality. By applying the strategy of KP adjustments to TRC conditions, we successfully reduced the strip thickness and produced high-quality strips without an inverse segregation layer on the strip surface.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116528"},"PeriodicalIF":5.3,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-30DOI: 10.1016/j.scriptamat.2024.116527
Liliana Romero-Resendiz , Yi Huang , Alexander J. Knowles , Joe Kelleher , Tung Lik Lee , Tayebeh Mousavi , Muhammad Naeem
Heterostructured materials have been demonstrated as a new route to improve the strength–ductility trade-off of metallic materials. However, their mechanical performance at cryogenic temperatures has been scarcely explored. This study investigates the mechanical properties and phase transformation of a heterostructured and antimicrobial stainless steel (HS&AMSS), 316L+Cu, at a cryogenic temperature of 77 K. By using in-situ neutron diffraction, we revealed real-time phase evolution under tensile deformation. The HS&AMSS demonstrated exceptional mechanical properties at 77 K, including a significantly higher yield strength of 1400 MPa combined with an excellent ductility of 36 % compared to conventional stainless steels and heterostructured multicomponent alloys. The outstanding mechanical performance is attributed to the synergistic effect of multiple strengthening and strain hardening mechanisms. These findings suggest that HS&AMSS is a promising material for applications requiring robust mechanical properties in cryogenic environments, such as hydrogen storage, aerospace, superconducting magnets and polar infrastructure.
{"title":"Exceptional strength–ductility combination of heterostructured stainless steel for cryogenic applications","authors":"Liliana Romero-Resendiz , Yi Huang , Alexander J. Knowles , Joe Kelleher , Tung Lik Lee , Tayebeh Mousavi , Muhammad Naeem","doi":"10.1016/j.scriptamat.2024.116527","DOIUrl":"10.1016/j.scriptamat.2024.116527","url":null,"abstract":"<div><div>Heterostructured materials have been demonstrated as a new route to improve the strength–ductility trade-off of metallic materials. However, their mechanical performance at cryogenic temperatures has been scarcely explored. This study investigates the mechanical properties and phase transformation of a heterostructured and antimicrobial stainless steel (HS&AMSS), 316L+Cu, at a cryogenic temperature of 77 K. By using in-situ neutron diffraction, we revealed real-time phase evolution under tensile deformation. The HS&AMSS demonstrated exceptional mechanical properties at 77 K, including a significantly higher yield strength of 1400 MPa combined with an excellent ductility of 36 % compared to conventional stainless steels and heterostructured multicomponent alloys. The outstanding mechanical performance is attributed to the synergistic effect of multiple strengthening and strain hardening mechanisms. These findings suggest that HS&AMSS is a promising material for applications requiring robust mechanical properties in cryogenic environments, such as hydrogen storage, aerospace, superconducting magnets and polar infrastructure.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116527"},"PeriodicalIF":5.3,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-28DOI: 10.1016/j.scriptamat.2024.116530
Nikita Polin , Konstantin P. Skokov , Alex Aubert , Hongguo Zhang , Burçak Ekitli , Esmaeil Adabifiroozjaei , Leopoldo Molina-Luna , Oliver Gutfleisch , Baptiste Gault
2:17 SmCo magnets with a quinary composition of Sm(Co,Cu,Fe,Zr)7+δ are industrially-relevant hard magnets used in high temperature and corrosive environments. Their complex cellular/lamellar nanostructure, consisting of ordered 2:17 phase cells, 1:5 phase cell boundaries and Z-phase (Zr-rich) lamellae, is essential for their high coercivity. However, the system's complexity makes it challenging to determine the contribution of each element or microstructural feature to coercivity. To disentangle the microstructure-property relationships, we simplified the system to binary and ternary SmCo7.7-xZrx (with ) magnets and conducted detailed micro- to atomic-scale analyses. Only Zr-containing magnets formed a cellular/lamellar nanostructure akin to industrial magnets, in Zr-rich regions with at least 1.4 at.% Zr, but without achieving high coercivity due to low elemental gradients in absence of Cu across cell boundaries. Data from Zr-poor areas of SmCo7.6Zr0.1 suggests that 2:17 phase twin boundaries facilitate cellular nanostructure formation by providing inhomogeneities for heterogeneous nucleation.
{"title":"Formation of cellular/lamellar nanostructure in Sm2Co17-type binary and ternary Sm-Co-Zr magnets","authors":"Nikita Polin , Konstantin P. Skokov , Alex Aubert , Hongguo Zhang , Burçak Ekitli , Esmaeil Adabifiroozjaei , Leopoldo Molina-Luna , Oliver Gutfleisch , Baptiste Gault","doi":"10.1016/j.scriptamat.2024.116530","DOIUrl":"10.1016/j.scriptamat.2024.116530","url":null,"abstract":"<div><div>2:17 SmCo magnets with a quinary composition of Sm(Co,Cu,Fe,Zr)<sub>7+δ</sub> are industrially-relevant hard magnets used in high temperature and corrosive environments. Their complex cellular/lamellar nanostructure, consisting of ordered 2:17 phase cells, 1:5 phase cell boundaries and Z-phase (Zr-rich) lamellae, is essential for their high coercivity. However, the system's complexity makes it challenging to determine the contribution of each element or microstructural feature to coercivity. To disentangle the microstructure-property relationships, we simplified the system to binary and ternary SmCo<sub>7.7-x</sub>Zr<sub>x</sub> (with <span><math><mrow><mi>x</mi><mo>=</mo><mn>0</mn><mspace></mspace><mrow><mtext>and</mtext><mspace></mspace></mrow><mn>0.1</mn></mrow></math></span>) magnets and conducted detailed micro- to atomic-scale analyses. Only Zr-containing magnets formed a cellular/lamellar nanostructure akin to industrial magnets, in Zr-rich regions with at least 1.4 at.% Zr, but without achieving high coercivity due to low elemental gradients in absence of Cu across cell boundaries. Data from Zr-poor areas of SmCo<sub>7.6</sub>Zr<sub>0.1</sub> suggests that 2:17 phase twin boundaries facilitate cellular nanostructure formation by providing inhomogeneities for heterogeneous nucleation.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116530"},"PeriodicalIF":5.3,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-27DOI: 10.1016/j.scriptamat.2024.116522
Sezer Picak
High- and medium-entropy alloys are a sub-class of multi-principal element alloys with an exceptional combination of strength and toughness arising from twinning– and transformation–induced plasticity. The underlying mechanisms responsible for the nucleation of deformation twinning and ɛ-martensite transformation in multi-principal element alloys still remains under intense debate. In this work, high-resolution transmission-electron microscopy was used to reveal the complex dislocation reactions behind deformation twinning and ɛ-martensite in a model NiCoCr. The existence of stair-rod and Shockley partials under uniaxial loading was demonstrated. The stair-rods dislocations with multiple Lomer-Cottrell locks play a crucial role in the formation of deformation twinning and ɛ-martensite. Lomer-Cottrell locks significantly contribute to work hardening behavior by acting as both dislocation barriers and sources. The results herein offer clarity regarding the strengthening mechanisms in multi-principal element alloys.
{"title":"The role of stair-rod dislocations on the twinning and martensitic transformation in single crystalline NiCoCr","authors":"Sezer Picak","doi":"10.1016/j.scriptamat.2024.116522","DOIUrl":"10.1016/j.scriptamat.2024.116522","url":null,"abstract":"<div><div>High- and medium-entropy alloys are a sub-class of multi-principal element alloys with an exceptional combination of strength and toughness arising from twinning– and transformation–induced plasticity. The underlying mechanisms responsible for the nucleation of deformation twinning and ɛ-martensite transformation in multi-principal element alloys still remains under intense debate. In this work, high-resolution transmission-electron microscopy was used to reveal the complex dislocation reactions behind deformation twinning and ɛ-martensite in a model NiCoCr. The existence of stair-rod and Shockley partials under uniaxial loading was demonstrated. The stair-rods dislocations with multiple Lomer-Cottrell locks play a crucial role in the formation of deformation twinning and ɛ-martensite. Lomer-Cottrell locks significantly contribute to work hardening behavior by acting as both dislocation barriers and sources. The results herein offer clarity regarding the strengthening mechanisms in multi-principal element alloys.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116522"},"PeriodicalIF":5.3,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-27DOI: 10.1016/j.scriptamat.2024.116506
Rishabh Dwivedi, Prafull Pandey
The present work reports the design of a cast ternary Al-3.8Ni-0.5Cr eutectic alloy for high-temperature applications with a minor Zr addition (0.15 at %). In the peak-aged condition (375 °C for 20 h), the alloy exhibited a hardness of 120 ± 3 HV and yield strengths of 355 ± 15, 225 ± 10, and 197 ± 8 MPa at 25, 200, and 250 °C, respectively. Notably, the alloy maintained a yield strength of 335 ± 25 MPa after long-term heat treatment at 375 °C for 100 h. The excellent microstructural stability and high-temperature strength are attributed to the presence of coherent and stable L1₂-ordered precipitates within the soft α-Al matrix of the eutectic phase. TEM weak-beam imaging revealed precipitate shearing via a planar dislocation glide mechanism, suggesting glide plane softening at 25 °C. Theoretical calculations predicted optimal strengthening from ordering, with peak strength achieved for precipitate sizes of ∼2.4 nm.
{"title":"Design of a cast Al-based Al-Ni-Cr-Zr eutectic alloy with excellent high temperature mechanical properties","authors":"Rishabh Dwivedi, Prafull Pandey","doi":"10.1016/j.scriptamat.2024.116506","DOIUrl":"10.1016/j.scriptamat.2024.116506","url":null,"abstract":"<div><div>The present work reports the design of a cast ternary Al-3.8Ni-0.5Cr eutectic alloy for high-temperature applications with a minor Zr addition (0.15 at %). In the peak-aged condition (375 °C for 20 h), the alloy exhibited a hardness of 120 ± 3 HV and yield strengths of 355 ± 15, 225 ± 10, and 197 ± 8 MPa at 25, 200, and 250 °C, respectively. Notably, the alloy maintained a yield strength of 335 ± 25 MPa after long-term heat treatment at 375 °C for 100 h. The excellent microstructural stability and high-temperature strength are attributed to the presence of coherent and stable L1₂-ordered precipitates within the soft α-Al matrix of the eutectic phase. TEM weak-beam imaging revealed precipitate shearing via a planar dislocation glide mechanism, suggesting glide plane softening at 25 °C. Theoretical calculations predicted optimal strengthening from ordering, with peak strength achieved for precipitate sizes of ∼2.4 nm.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116506"},"PeriodicalIF":5.3,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Scandium aluminum nitride (ScxAl1-xN) has been championed as the future material and controlling its polarity is anticipated to bring improvement to the performance of broad range electronic devices, including radio frequency (RF) filter. In this study, the polarity of ScxAl1-xN thin films fabricated via sputtering was successfully inversed from metal (M)-polar to nitrogen (N)-polar by addition of silicon (Si) in the range of 2.5–20.0 at.%. Addition of approximately 10 at % Si into ScxAl1-xN brought the optimum piezoelectric coefficient d33, particularly for x = 0.1 and 0.2 where the resulted d33 was found to be similar with that without Si addition. However, addition of Si could not inverse the polarity of Sc0.4Al0.6N, suggesting that the concentration of both Si and scandium (Sc) governed the resulting polarity. Effect of Si addition into ScAlN on changes in polarity, crystal structure as well as plausible mechanism were further discussed herein.
{"title":"Effect of Si addition on polarity inversion in scandium aluminum nitride piezoelectric thin films","authors":"Sri Ayu Anggraini, Masato Uehara, Kenji Hirata, Taisei Motomura, Hiroshi Yamada, Morito Akiyama","doi":"10.1016/j.scriptamat.2024.116523","DOIUrl":"10.1016/j.scriptamat.2024.116523","url":null,"abstract":"<div><div>Scandium aluminum nitride (Sc<sub>x</sub>Al<sub>1-x</sub>N) has been championed as the future material and controlling its polarity is anticipated to bring improvement to the performance of broad range electronic devices, including radio frequency (RF) filter. In this study, the polarity of Sc<sub>x</sub>Al<sub>1-x</sub>N thin films fabricated via sputtering was successfully inversed from metal (M)-polar to nitrogen (N)-polar by addition of silicon (Si) in the range of 2.5–20.0 at.%. Addition of approximately 10 at % Si into Sc<sub>x</sub>Al<sub>1-x</sub>N brought the optimum piezoelectric coefficient <em>d</em><sub>33</sub>, particularly for <em>x</em> = 0.1 and 0.2 where the resulted <em>d</em><sub>33</sub> was found to be similar with that without Si addition. However, addition of Si could not inverse the polarity of Sc<sub>0.4</sub>Al<sub>0.6</sub>N, suggesting that the concentration of both Si and scandium (Sc) governed the resulting polarity. Effect of Si addition into ScAlN on changes in polarity, crystal structure as well as plausible mechanism were further discussed herein.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116523"},"PeriodicalIF":5.3,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-27DOI: 10.1016/j.scriptamat.2024.116518
Oluwagbemiga P. Ojo , Wilarachchige D.C.B. Gunatilleke , Hsin Wang , George S. Nolas
Phase-pure CuIn2Se4, a ternary metal chalcogenide that forms in a disordered stannite crystal structure, was synthesized to investigate the structure thermal property relationships as well as reveal the origin of the ultralow thermal conductivity this material possesses over a large temperature range. Modeling of the temperature-dependent heat capacity and thermal conductivity revealed distinctive thermal properties and large lattice anharmonicity. Electron localization function calculations highlight the asymmetric bonding inherent to CuIn2Se4, which together with lattice anharmonicity directly impacts the thermal properties. Our findings reveal the specific atomic arrangement and bonding governing the thermal properties of this ternary metal chalcogenide. Our findings underscore the specific atomic arrangement and bonding governing the thermal properties in this ternary chalcogenide. This study advances the fundamental understanding of stannites, and our findings can be applied to these and other multinary metal chalcogenides of interest for applications where low thermal conductivity is desirable.
{"title":"Structural and thermal properties and the origin of the ultralow thermal conductivity in the defect stannite CuIn2Se4","authors":"Oluwagbemiga P. Ojo , Wilarachchige D.C.B. Gunatilleke , Hsin Wang , George S. Nolas","doi":"10.1016/j.scriptamat.2024.116518","DOIUrl":"10.1016/j.scriptamat.2024.116518","url":null,"abstract":"<div><div>Phase-pure CuIn<sub>2</sub>Se<sub>4</sub>, a ternary metal chalcogenide that forms in a disordered stannite crystal structure, was synthesized to investigate the structure thermal property relationships as well as reveal the origin of the ultralow thermal conductivity this material possesses over a large temperature range. Modeling of the temperature-dependent heat capacity and thermal conductivity revealed distinctive thermal properties and large lattice anharmonicity. Electron localization function calculations highlight the asymmetric bonding inherent to CuIn<sub>2</sub>Se<sub>4</sub>, which together with lattice anharmonicity directly impacts the thermal properties. Our findings reveal the specific atomic arrangement and bonding governing the thermal properties of this ternary metal chalcogenide. Our findings underscore the specific atomic arrangement and bonding governing the thermal properties in this ternary chalcogenide. This study advances the fundamental understanding of stannites, and our findings can be applied to these and other multinary metal chalcogenides of interest for applications where low thermal conductivity is desirable.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116518"},"PeriodicalIF":5.3,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-25DOI: 10.1016/j.scriptamat.2024.116519
Jeong-Woo Sun , Temesgen Tadeyos Zate , Woo-Jin Choi , Geon-Ju Lee , Yoon Sang Jeong , Sang-Goo Lee , Jong Eun Ryu , Wook Jo
Alternating current (AC) poling has been found to be more effective in optimizing the performance of [001]-oriented rhombohedral relaxor-PbTiO3 single crystals. However, these materials undergo ferroelectric phase transformations, during which structural changes result in loss of polarization and property degradation. In this study, we focus on a strategy to mitigate phase transformation-induced depolarization in Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single crystals through high-temperature AC poling. Our results reveal that thermal depolarization is significantly reduced when AC poling is conducted at high temperature near the rhombohedral-to-tetragonal transformation temperature compared to the room-temperature poling. Furthermore, in-situ X-ray diffraction and Raman spectroscopy demonstrates that high-temperature AC poling can achieve a metastable phase and suppress symmetry changes during the ferroelectric phase transformation, contributing to reduced property degradation in the materials. Our findings highlight the potential of a novel domain engineering technique to enhance structural stability and mitigate depolarization in PMN-PT single crystals.
{"title":"Suppressing phase transformation-induced depolarization in PMN-PT single crystals through high-temperature AC poling","authors":"Jeong-Woo Sun , Temesgen Tadeyos Zate , Woo-Jin Choi , Geon-Ju Lee , Yoon Sang Jeong , Sang-Goo Lee , Jong Eun Ryu , Wook Jo","doi":"10.1016/j.scriptamat.2024.116519","DOIUrl":"10.1016/j.scriptamat.2024.116519","url":null,"abstract":"<div><div>Alternating current (AC) poling has been found to be more effective in optimizing the performance of [001]-oriented rhombohedral relaxor-PbTiO<sub>3</sub> single crystals. However, these materials undergo ferroelectric phase transformations, during which structural changes result in loss of polarization and property degradation. In this study, we focus on a strategy to mitigate phase transformation-induced depolarization in Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3</sub> (PMN-PT) single crystals through high-temperature AC poling. Our results reveal that thermal depolarization is significantly reduced when AC poling is conducted at high temperature near the rhombohedral-to-tetragonal transformation temperature compared to the room-temperature poling. Furthermore, <em>in-situ</em> X-ray diffraction and Raman spectroscopy demonstrates that high-temperature AC poling can achieve a metastable phase and suppress symmetry changes during the ferroelectric phase transformation, contributing to reduced property degradation in the materials. Our findings highlight the potential of a novel domain engineering technique to enhance structural stability and mitigate depolarization in PMN-PT single crystals.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116519"},"PeriodicalIF":5.3,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-24DOI: 10.1016/j.scriptamat.2024.116517
Pengzhan Cai , He Li , Ling Zhang , Meng Wang , Ziyong Hou , Xiaoxu Huang
Nanolamellar pearlitic steel with simultaneous improvement of strength and ductility was achieved by low temperature annealing at 300 °C in a high-carbon (0.92 wt.%) pearlitic steel. The sample annealed for 120 min (300 °C-120 min) exhibits a yield strength of 2.15 ± 0.03 GPa, much higher than that of the cold-drawn counterpart (1.88 GPa). The uniform elongation is 6.0 ± 0.7 %, comparable to that of the patented one (the rod before cold drawing). High density dislocations, dispersed nano-carbides embedded in ferrite lamellae, together with basically continuous cementite lamellae ought to be the ovreall ultra-high strength contributions. Furthermore, the excellent combination of strength and ductility were briefly discussed in terms of the microstructure.
{"title":"Simultaneous improvement of strength and ductility in an ultra-high strength pearlitic steel achieved by high density nano-carbides","authors":"Pengzhan Cai , He Li , Ling Zhang , Meng Wang , Ziyong Hou , Xiaoxu Huang","doi":"10.1016/j.scriptamat.2024.116517","DOIUrl":"10.1016/j.scriptamat.2024.116517","url":null,"abstract":"<div><div>Nanolamellar pearlitic steel with simultaneous improvement of strength and ductility was achieved by low temperature annealing at 300 °C in a high-carbon (0.92 wt.%) pearlitic steel. The sample annealed for 120 min (300 °C-120 min) exhibits a yield strength of 2.15 ± 0.03 GPa, much higher than that of the cold-drawn counterpart (1.88 GPa). The uniform elongation is 6.0 ± 0.7 %, comparable to that of the patented one (the rod before cold drawing). High density dislocations, dispersed nano-carbides embedded in ferrite lamellae, together with basically continuous cementite lamellae ought to be the ovreall ultra-high strength contributions. Furthermore, the excellent combination of strength and ductility were briefly discussed in terms of the microstructure.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116517"},"PeriodicalIF":5.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-24DOI: 10.1016/j.scriptamat.2024.116526
Shubin Wang , Junfeng Wang , Peiying Shi , Yixuan Lin , Kai Huang , Xianbing Zhang , Shengbing Yang , Huwei Sun , Da Shu , Baode Sun
Poor oxidation resistance at elevated temperatures is one of the main bottlenecks in bringing refractory high-entropy alloys (RHEAs) to application. In this work, we turn this shortcoming into a benefit by using a transient oxidation process (2–3 s) to generate a crack-free oxidation scale about 10 µm thick on the surface of a bulk TiZrHfNbTa alloy. During oxidation, oxygen ingress promotes the spinodal decomposition and inherited lamellar composite structure consisting of NbTa-rich BCC phase and monoclinic (Zr, Hf)O2 oxides, which jointly contribute to the generation of mechanically gradient oxide scale. The adherent oxide scale significantly increases the hardness and wear resistance of the surface, while maintaining the intrinsic ductility of the bulk alloy and good biocompatibility. This work advances our understanding of the initial oxidation mechanisms of compositionally complex refractory alloys and contributes to exploring effective anti-wear strategies for orthopedic applications.
{"title":"Improving tribological property of TiZrHfNbTa high entropy alloy by transient oxidation for biomedical application","authors":"Shubin Wang , Junfeng Wang , Peiying Shi , Yixuan Lin , Kai Huang , Xianbing Zhang , Shengbing Yang , Huwei Sun , Da Shu , Baode Sun","doi":"10.1016/j.scriptamat.2024.116526","DOIUrl":"10.1016/j.scriptamat.2024.116526","url":null,"abstract":"<div><div>Poor oxidation resistance at elevated temperatures is one of the main bottlenecks in bringing refractory high-entropy alloys (RHEAs) to application. In this work, we turn this shortcoming into a benefit by using a transient oxidation process (2–3 s) to generate a crack-free oxidation scale about 10 µm thick on the surface of a bulk TiZrHfNbTa alloy. During oxidation, oxygen ingress promotes the spinodal decomposition and inherited lamellar composite structure consisting of NbTa-rich BCC phase and monoclinic (Zr, Hf)O<sub>2</sub> oxides, which jointly contribute to the generation of mechanically gradient oxide scale. The adherent oxide scale significantly increases the hardness and wear resistance of the surface, while maintaining the intrinsic ductility of the bulk alloy and good biocompatibility. This work advances our understanding of the initial oxidation mechanisms of compositionally complex refractory alloys and contributes to exploring effective anti-wear strategies for orthopedic applications.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"258 ","pages":"Article 116526"},"PeriodicalIF":5.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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