Pub Date : 2025-01-21DOI: 10.1016/j.jmst.2024.11.071
Junyu Chen, Fei Liu, Gang Fang, Upadrasta Ramamurty
Functional fatigue in the superelastic NiTi shape memory alloys occurs due to the accumulation of dislocations and retention of martensite with the cyclic loading. These mechanisms reduce the amount of the material available for the stress-induced transformation and, thus, lower the elastocaloric effect that originates from the stress-induced latent heat variations. In this study, the individual contributions of the micromechanisms responsible for the functional fatigue in superelastic NiTi at different maximum tensile stress (σmax) are critically examined. Results show that the elastocaloric effect degrades significantly with cycling, and the saturated degraded value increases with σmax; the steady-state adiabatic temperature change is unexpectedly non-proportional to σmax. An overheating treatment (‘healing’) after mechanical fatigue reverts the retained martensite into austenite, making it available for subsequent transformation and restoring the elastocaloric effect significantly. Such a restoration increases exponentially with σmax. Consequently, the steady-state elastocaloric effect of the healed NiTi is proportional to σmax and can reach more than twice that of NiTi without healing. The work sheds light on the physical origins of elastocaloric degradation of superelastic NiTi and also provides a feasible method for ameliorating functional fatigue.
{"title":"Intermittent healing for alleviating the functional fatigue and restoration of the elastocaloric effect in superelastic NiTi shape memory alloy","authors":"Junyu Chen, Fei Liu, Gang Fang, Upadrasta Ramamurty","doi":"10.1016/j.jmst.2024.11.071","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.11.071","url":null,"abstract":"Functional fatigue in the superelastic NiTi shape memory alloys occurs due to the accumulation of dislocations and retention of martensite with the cyclic loading. These mechanisms reduce the amount of the material available for the stress-induced transformation and, thus, lower the elastocaloric effect that originates from the stress-induced latent heat variations. In this study, the individual contributions of the micromechanisms responsible for the functional fatigue in superelastic NiTi at different maximum tensile stress (<em>σ</em><sub>max</sub>) are critically examined. Results show that the elastocaloric effect degrades significantly with cycling, and the saturated degraded value increases with <em>σ</em><sub>max</sub>; the steady-state adiabatic temperature change is unexpectedly non-proportional to <em>σ</em><sub>max</sub>. An overheating treatment (‘healing’) after mechanical fatigue reverts the retained martensite into austenite, making it available for subsequent transformation and restoring the elastocaloric effect significantly. Such a restoration increases exponentially with <em>σ</em><sub>max</sub>. Consequently, the steady-state elastocaloric effect of the healed NiTi is proportional to <em>σ</em><sub>max</sub> and can reach more than twice that of NiTi without healing. The work sheds light on the physical origins of elastocaloric degradation of superelastic NiTi and also provides a feasible method for ameliorating functional fatigue.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"22 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aluminum alloys that are additively manufactured using the laser powder bed fusion (LPBF) suffer from relatively poor high cycle fatigue (HCF) resistance. In an effort to alleviate this, a high-strength Al alloy, Al-Mn-Mg-Sc-Zr, with columnar, equiaxed, and bi-modal microstructures was produced by varying the scanning velocity and the substrate temperature during the LPBF process. The tensile strength of LPBF Al-Mn-Mg-Sc-Zr alloy is 475 ± 5 – 516 ± 6 MPa with favorable elongation of approximately 11 %, higher than that of most of the other Al alloys, including conventional high-strength rolled/ECAP Al alloys and AM Al-Mg-Sc-Zr alloys. Specimens with bimodal microstructure and specimens with fully equiaxed microstructure both show a fatigue strength of 230 MPa (at 107 loading cycles), which is the highest among those reported for the LPBF Al alloys. The deformation synergy in the bimodal microstructure also improves the fatigue resistance in the strain-controlled low cycle fatigue (LCF) regime. The equiaxed microstructure restricts the to-and-fro dislocation motion during cyclic loading, which, in turn, minimizes the strain localization. At the later stages of strain accumulation, microcracks form at the grain boundaries, limiting the further improvement of the alloy's fatigue strength. This study demonstrates microstructural tailoring through AM enables improvement of the fatigue resistance of aluminum alloys.
{"title":"Effect of columnar-to-equiaxed microstructural transition on the fatigue performance of a laser powder bed fused high-strength Al alloy","authors":"Jin'e Sun, Punit Kumar, Pei Wang, Upadrasta Ramamurty, Xuanhui Qu, Baicheng Zhang","doi":"10.1016/j.jmst.2024.12.026","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.12.026","url":null,"abstract":"Aluminum alloys that are additively manufactured using the laser powder bed fusion (LPBF) suffer from relatively poor high cycle fatigue (HCF) resistance. In an effort to alleviate this, a high-strength Al alloy, Al-Mn-Mg-Sc-Zr, with columnar, equiaxed, and bi-modal microstructures was produced by varying the scanning velocity and the substrate temperature during the LPBF process. The tensile strength of LPBF Al-Mn-Mg-Sc-Zr alloy is 475 ± 5 – 516 ± 6 MPa with favorable elongation of approximately 11 %, higher than that of most of the other Al alloys, including conventional high-strength rolled/ECAP Al alloys and AM Al-Mg-Sc-Zr alloys. Specimens with bimodal microstructure and specimens with fully equiaxed microstructure both show a fatigue strength of 230 MPa (at 10<sup>7</sup> loading cycles), which is the highest among those reported for the LPBF Al alloys. The deformation synergy in the bimodal microstructure also improves the fatigue resistance in the strain-controlled low cycle fatigue (LCF) regime. The equiaxed microstructure restricts the to-and-fro dislocation motion during cyclic loading, which, in turn, minimizes the strain localization. At the later stages of strain accumulation, microcracks form at the grain boundaries, limiting the further improvement of the alloy's fatigue strength. This study demonstrates microstructural tailoring through AM enables improvement of the fatigue resistance of aluminum alloys.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"105 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-18DOI: 10.1016/j.jmst.2024.12.023
Liuyong He, Jiang Zheng, Qiyang He, Tianjiao Li, Haoge Shou, Dongdi Yin, Shengwen Bai, Bin Jiang, Fusheng Pan
Aging precipitation can effectively enhance the strength of Mg–RE alloys, but it is usually accompanied by a significant decrease in ductility, thus the strength–ductility trade-off is a longstanding challenge. In this study, we report a new strategy that coupled pre-deformation (pre-tension along the extrusion direction (ED) followed by pre-compression along transverse direction (TD)) with artificial aging to achieve an exceptional strength–ductility synergy in the WE54 alloy at RT. We analyzed the microstructure, deformation modes and mechanical properties of four samples: T6 (artificial aging), PT-T6 (pre-tension + artificial aging), PC-T6 (pre-compression + artificial aging), and PTC-T6 (coupled pre-deformation + artificial aging). The PTC-T6 sample exhibited the superior strength–plasticity synergy, showing a strength increase of 111.9 MPa over the T6 sample and only a slight decrease in elongation to fracture. The PTC-T6 sample features finer and denser precipitates, along with a higher dislocation density, particularly a significant presence of <c+a> dislocations. This microstructural configuration enhances strength and facilitates the activation of pyramidal slip, which is the primary factor underlying its superior strength–ductility synergy.
{"title":"Achieving superior strength and ductility synergy of WE54 alloy via combined dislocation introduction and twinning","authors":"Liuyong He, Jiang Zheng, Qiyang He, Tianjiao Li, Haoge Shou, Dongdi Yin, Shengwen Bai, Bin Jiang, Fusheng Pan","doi":"10.1016/j.jmst.2024.12.023","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.12.023","url":null,"abstract":"Aging precipitation can effectively enhance the strength of Mg–RE alloys, but it is usually accompanied by a significant decrease in ductility, thus the strength–ductility trade-off is a longstanding challenge. In this study, we report a new strategy that coupled pre-deformation (pre-tension along the extrusion direction (ED) followed by pre-compression along transverse direction (TD)) with artificial aging to achieve an exceptional strength–ductility synergy in the WE54 alloy at RT. We analyzed the microstructure, deformation modes and mechanical properties of four samples: T6 (artificial aging), PT-T6 (pre-tension + artificial aging), PC-T6 (pre-compression + artificial aging), and PTC-T6 (coupled pre-deformation + artificial aging). The PTC-T6 sample exhibited the superior strength–plasticity synergy, showing a strength increase of 111.9 MPa over the T6 sample and only a slight decrease in elongation to fracture. The PTC-T6 sample features finer and denser precipitates, along with a higher dislocation density, particularly a significant presence of <<em>c</em>+<em>a</em>> dislocations. This microstructural configuration enhances strength and facilitates the activation of pyramidal slip, which is the primary factor underlying its superior strength–ductility synergy.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"98 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-18DOI: 10.1016/j.jmst.2024.11.070
Yangming Hu, Liansheng Li, Xiangxiang Fu, Wanting Li, Yuanfu Deng
The interface instability between composite solid electrolytes (CSEs) and lithium anode significantly shortens the lifespan of all-solid-state lithium batteries (ASSLBs) with high areal capacity. In this work, a CSE featuring a trilayer architecture is developed by incorporating a thin polyethylene (PE) separator into a blending polymer matrix of poly(ethylene oxide) and poly(vinylidene fluoride) (PEO-PVDF) through a hot pressing technique. This structural design provides complementary functions: the flexible outer layers confine lithium deposition within a restricted area, while the robust interlayer prevents lithium dendrite penetration. Additionally, the incorporation of LiNO3 significantly enhances the stability of the CSE/Li interface by gradually forming a Li3N-rich interfacial film, which promotes uniform lithium deposition. Consequently, the assembled Li||Li symmetrical cell demonstrates stable cycling for over 6000 h at a current density of 0.2 mA cm–2 with an areal capacity of 1.2 mAh cm–2. More attractively, ASSLBs constructed with the designed CSEs, high mass loading LFP/NCM811 (LFP: LiFePO4; NCM811: LiNi0.8Co0.1Mn0.1O2) cathodes (≥ 12 mg cm–2), and lithium metal anodes deliver superior cycling performance without short-circuiting at current densities of 0.3/0.2 mA cm–2, respectively. This work offers critical insights for the design of high-performance ASSLBs with improved durability at high areal capacities.
复合固体电解质（CSE）与锂负极之间的界面不稳定性大大缩短了高容量全固态锂电池（ASSLB）的使用寿命。在这项研究中，通过热压技术将薄聚乙烯（PE）隔膜加入到聚环氧乙烷和聚偏氟乙烯（PEO-PVDF）的混合聚合物基体中，开发出了一种具有三层结构的 CSE。这种结构设计具有互补功能：柔性外层将锂沉积限制在一个有限的区域内，而坚固的中间层则防止锂枝晶渗透。此外，LiNO3 的加入通过逐渐形成富含 Li3N 的界面膜，显著增强了 CSE/Li 界面的稳定性，从而促进了锂的均匀沉积。因此，组装好的锂对称电池在 0.2 mA cm-2 的电流密度下可稳定循环 6000 小时以上，平均容量为 1.2 mAh cm-2。更吸引人的是，使用所设计的 CSE、高负载 LFP/NCM811（LFP：LiFePO4；NCM811：LiNi0.8Co0.1Mn0.1O2）正极（≥ 12 mg cm-2）和锂金属阳极构建的 ASSLB 在电流密度分别为 0.3/0.2 mA cm-2 时具有优异的无短路循环性能。这项研究为设计高性能 ASSLB 提供了重要的启示，可提高高电容下的耐用性。
{"title":"A novel designed trilayer composite solid electrolyte enabling high-areal-capacity all-solid-state lithium batteries with long lifespan","authors":"Yangming Hu, Liansheng Li, Xiangxiang Fu, Wanting Li, Yuanfu Deng","doi":"10.1016/j.jmst.2024.11.070","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.11.070","url":null,"abstract":"The interface instability between composite solid electrolytes (CSEs) and lithium anode significantly shortens the lifespan of all-solid-state lithium batteries (ASSLBs) with high areal capacity. In this work, a CSE featuring a trilayer architecture is developed by incorporating a thin polyethylene (PE) separator into a blending polymer matrix of poly(ethylene oxide) and poly(vinylidene fluoride) (PEO-PVDF) through a hot pressing technique. This structural design provides complementary functions: the flexible outer layers confine lithium deposition within a restricted area, while the robust interlayer prevents lithium dendrite penetration. Additionally, the incorporation of LiNO<sub>3</sub> significantly enhances the stability of the CSE/Li interface by gradually forming a Li<sub>3</sub>N-rich interfacial film, which promotes uniform lithium deposition. Consequently, the assembled Li||Li symmetrical cell demonstrates stable cycling for over 6000 h at a current density of 0.2 mA cm<sup>–2</sup> with an areal capacity of 1.2 mAh cm<sup>–2</sup>. More attractively, ASSLBs constructed with the designed CSEs, high mass loading LFP/NCM811 (LFP: LiFePO<sub>4</sub>; NCM811: LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub>) cathodes (≥ 12 mg cm<sup>–2</sup>), and lithium metal anodes deliver superior cycling performance without short-circuiting at current densities of 0.3/0.2 mA cm<sup>–2</sup>, respectively. This work offers critical insights for the design of high-performance ASSLBs with improved durability at high areal capacities.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"7 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A simple model, namely the equivalence precipitation model of η-type precipitate, has been established based on CALPHAD for the Al-Zn-Mg-1.5Cu alloy with a rich Al angle. The relationship of the theoretical mass fraction of η-type precipitate, the total content of Zn and Mg, and the Zn/Mg ratio is disclosed through the equivalence precipitation model. Moreover, the evolution of microstructure and mechanical properties in alloys with different theoretical mass fractions of η-type precipitate are explored. The findings imply that the fluctuation of theoretical mass fraction of η-type precipitate in the alloy primarily impacts the precipitation behavior of η-type precipitate. The increase of theoretical mass fraction of η-type precipitate leads to a higher volume fraction of η' phase, resulting in an improvement in strength. However, alloys with a higher theoretical mass fraction of η-type precipitate are inclined to form the quench-induced η phase, showing higher quench sensitivity. These results are attributed to the regulation of the precipitation behavior by the total content of Zn and Mg and the Zn/Mg ratio with different theoretical mass fractions of η-type precipitate. Experimental verification has demonstrated that the equivalence precipitation model can effectively predict precipitation strengthening and evaluate the quench sensitivity of Al-Zn-Mg-1.5Cu alloys.
以 CALPHAD 为基础，针对富铝角的 Al-Zn-Mg-1.5Cu 合金建立了一个简单的模型，即 η 型沉淀的等价沉淀模型。通过等价沉淀模型，揭示了η型沉淀理论质量分数、锌和镁的总含量以及锌/镁比的关系。此外，还探讨了η型沉淀理论质量分数不同的合金的微观结构和机械性能的演变。研究结果表明，合金中 η 型析出物理论质量分数的波动主要影响 η 型析出物的析出行为。η型沉淀理论质量分数的增加会导致η'相的体积分数增加，从而提高强度。然而，η型析出物理论质量分数较高的合金倾向于形成淬火诱导的η相，表现出较高的淬火敏感性。这些结果归因于 Zn 和 Mg 的总含量以及 Zn/Mg 比对析出行为的调节作用，η 型沉淀的理论质量分数不同。实验验证表明，等效析出模型可以有效地预测析出强化并评估铝-锌-镁-1.5 铜合金的淬火敏感性。
{"title":"A simple model revealing the evolution of mechanical properties in Al-Zn-Mg-Cu alloys with a rich Al angle based on CALPHAD","authors":"Xiyu He, Xuehong Xu, Xiang Xiao, Guojun Wang, Yunlai Deng, Yunqiang Fan","doi":"10.1016/j.jmst.2024.12.022","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.12.022","url":null,"abstract":"A simple model, namely the equivalence precipitation model of η-type precipitate, has been established based on CALPHAD for the Al-Zn-Mg-1.5Cu alloy with a rich Al angle. The relationship of the theoretical mass fraction of η-type precipitate, the total content of Zn and Mg, and the Zn/Mg ratio is disclosed through the equivalence precipitation model. Moreover, the evolution of microstructure and mechanical properties in alloys with different theoretical mass fractions of η-type precipitate are explored. The findings imply that the fluctuation of theoretical mass fraction of η-type precipitate in the alloy primarily impacts the precipitation behavior of η-type precipitate. The increase of theoretical mass fraction of η-type precipitate leads to a higher volume fraction of η' phase, resulting in an improvement in strength. However, alloys with a higher theoretical mass fraction of η-type precipitate are inclined to form the quench-induced η phase, showing higher quench sensitivity. These results are attributed to the regulation of the precipitation behavior by the total content of Zn and Mg and the Zn/Mg ratio with different theoretical mass fractions of η-type precipitate. Experimental verification has demonstrated that the equivalence precipitation model can effectively predict precipitation strengthening and evaluate the quench sensitivity of Al-Zn-Mg-1.5Cu alloys.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"31 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Perovskite oxides (ABO3) are thought to be promising electrocatalysts for oxygen evolution reaction (OER), but their specific surface area (SSA) is too low (usually < 10 m2 g-1). Developing advanced ABO3 electrocatalysts with high SSA and optimized structure is of great significance but remains a tremendous challenge. Herein, we propose a general strategy for fabrication of mesoporous perovskite oxide nanosheets (MPONs) with controllable atomic doping via self-sacrificial template-induced nanostructure modulation. A variety of MPONs including LaFeO3, A-site-doped LaFeO3 (A-LaFeO3, where A is Pr, Nd, Sm, Eu, or Gd) and B-site-doped LaFeO3 (B-LaFeO3, where B is Mn, Co, Ni, Cu, or Zn) have been achieved. Interestingly, it is discovered that the catalytic activities of A-LaFeO3 MPONs as OER catalysts are overall higher than those of B-LaFeO3 ones. Especially, the screened Eu-LaFeO3 MPONs only require a low overpotential of 267 mV at 10 mA cm-2, outperforming most reported perovskite oxides. The superior catalytic activity of Eu-LaFeO3 MPONs is attributed to their favorable porous structure, which increases the density of active sites, and enhanced lattice oxygen participation, which improves the intrinsic activity. This study provides guidance for the design and controlled synthesis of advanced rare-earth-doped MPONs with ultrahigh SSA for enhanced electrocatalysis.
{"title":"Ultrahigh specific surface area mesoporous perovskite oxide nanosheets with rare-earth-enhanced lattice oxygen participation for superior water oxidation","authors":"Biao Wang, Xiangrui Wu, Suyue Jia, Jiayi Tang, Hao Wu, Xuan Wang, Shengyong Gao, Hao Li, Haijiao Lu, Gengtao Fu, Xiangkang Meng, Shaochun Tang","doi":"10.1016/j.jmst.2024.11.069","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.11.069","url":null,"abstract":"Perovskite oxides (ABO<sub>3</sub>) are thought to be promising electrocatalysts for oxygen evolution reaction (OER), but their specific surface area (SSA) is too low (usually < 10 m<sup>2</sup> g<sup>-1</sup>). Developing advanced ABO<sub>3</sub> electrocatalysts with high SSA and optimized structure is of great significance but remains a tremendous challenge. Herein, we propose a general strategy for fabrication of mesoporous perovskite oxide nanosheets (MPONs) with controllable atomic doping via self-sacrificial template-induced nanostructure modulation. A variety of MPONs including LaFeO<sub>3</sub>, A-site-doped LaFeO<sub>3</sub> (A-LaFeO<sub>3</sub>, where A is Pr, Nd, Sm, Eu, or Gd) and B-site-doped LaFeO<sub>3</sub> (B-LaFeO<sub>3</sub>, where B is Mn, Co, Ni, Cu, or Zn) have been achieved. Interestingly, it is discovered that the catalytic activities of A-LaFeO<sub>3</sub> MPONs as OER catalysts are overall higher than those of B-LaFeO<sub>3</sub> ones. Especially, the screened Eu-LaFeO<sub>3</sub> MPONs only require a low overpotential of 267 mV at 10 mA cm<sup>-2</sup>, outperforming most reported perovskite oxides. The superior catalytic activity of Eu-LaFeO<sub>3</sub> MPONs is attributed to their favorable porous structure, which increases the density of active sites, and enhanced lattice oxygen participation, which improves the intrinsic activity. This study provides guidance for the design and controlled synthesis of advanced rare-earth-doped MPONs with ultrahigh SSA for enhanced electrocatalysis.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"14 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-16DOI: 10.1016/j.jmst.2024.11.014
Yao-Jie Kong, Hong-Ying Li, Hui-Jin Tao, Wen-Jian Liu
The precipitation and coarsening behavior of L12 nanophases in Al-0.15Zr-0.15Er-0.15Yb-xSc (wt. %) alloys during aging were characterized by Double-Cs-corrected STEM, TEM, microhardness testing, electrical conductivity measurement, and first-principles calculations. The results indicate that the Al3(Yb, Er) initiates precipitation at approximately 175 °C with substantial precipitation occurring at 250 °C. The Al3Sc and Al3Zr precipitate at approximately 325 and 450 °C, respectively. The core/shell precipitates initially form in Al-Zr-Er-Yb-Sc alloys consisting of an Al3(Yb, Er) core, an Al3Sc inner shell, and an Al3Zr outer shell. Upon prolonged aging, the core and inner shell remain as the Al3(Yb, Er) and Al3Sc, respectively, with the outer shell transforming into Al3(Yb, Er, Zr), and the interface with α-Al remaining as the Al3Zr. The precipitation evolution of the core-shell phases aligns with thermodynamic predictions based on solute segregation energies and phase interface energies. The increase of Sc content can effectively improve the aging response rate and strength of alloys. A modest Sc addition notably improves the coarsening resistance of the precipitation, while an excessive amount does not further improve this resistance.
采用双cs校正的STEM、TEM、显微硬度测试、电导率测量和第一性原理计算等方法研究了Al-0.15Zr-0.15Er-0.15Yb-xSc （wt. %）合金时效过程中L12纳米相的析出和粗化行为。结果表明，Al3（Yb, Er）在175℃左右开始析出，250℃时开始大量析出。Al3Sc和Al3Zr分别在325℃和450℃左右析出。在Al-Zr-Er-Yb-Sc合金中，芯壳相最初形成于由Al3（Yb, Er）芯、Al3Sc内壳和Al3Zr外壳组成的合金中。时效延长后，芯层和内层分别保持Al3（Yb, Er）和Al3Sc，外层转变为Al3(Yb, Er, Zr)，与α-Al的界面保持为Al3Zr。核壳相的析出演化符合基于溶质偏析能和相界面能的热力学预测。Sc含量的增加能有效提高合金的时效响应率和强度。适量添加Sc可显著提高析出物的抗粗化性能，而过量添加Sc则不能进一步提高其抗粗化性能。
{"title":"The precipitation evolution and coarsening resistance of dilute Al-Zr-Er-Yb (-Sc) alloys","authors":"Yao-Jie Kong, Hong-Ying Li, Hui-Jin Tao, Wen-Jian Liu","doi":"10.1016/j.jmst.2024.11.014","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.11.014","url":null,"abstract":"The precipitation and coarsening behavior of L1<sub>2</sub> nanophases in Al-0.15Zr-0.15Er-0.15Yb-<em>x</em>Sc (wt. %) alloys during aging were characterized by Double-Cs-corrected STEM, TEM, microhardness testing, electrical conductivity measurement, and first-principles calculations. The results indicate that the Al<sub>3</sub>(Yb, Er) initiates precipitation at approximately 175 °C with substantial precipitation occurring at 250 °C. The Al<sub>3</sub>Sc and Al<sub>3</sub>Zr precipitate at approximately 325 and 450 °C, respectively. The core/shell precipitates initially form in Al-Zr-Er-Yb-Sc alloys consisting of an Al<sub>3</sub>(Yb, Er) core, an Al<sub>3</sub>Sc inner shell, and an Al<sub>3</sub>Zr outer shell. Upon prolonged aging, the core and inner shell remain as the Al<sub>3</sub>(Yb, Er) and Al<sub>3</sub>Sc, respectively, with the outer shell transforming into Al<sub>3</sub>(Yb, Er, Zr), and the interface with α-Al remaining as the Al<sub>3</sub>Zr. The precipitation evolution of the core-shell phases aligns with thermodynamic predictions based on solute segregation energies and phase interface energies. The increase of Sc content can effectively improve the aging response rate and strength of alloys. A modest Sc addition notably improves the coarsening resistance of the precipitation, while an excessive amount does not further improve this resistance.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"96 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference (EMI) shielding and wave-absorbing materials. Hence, a densification strategy was proposed to fabricate multifunctional rigid polyimide (PI) composite foam. As a result, the composite PI foam exhibits excellent mechanical properties, with tensile and bending strengths of 4.7 and 21.1 MPa, respectively. Moreover, the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient (A) of 0.71, coupled with an X-band (8.2–12.4 GHz) EMI rating of 44 dB (2 mm) due to its high conductivity (20.29 ms/mm). Satisfyingly, the composite PI foam also has an optimal reflection loss (RL) of up to −46.4 dB and an effective absorption bandwidth (EAB) (RL < −10 dB) that covers the entire X-band. Meanwhile, the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages (3–9 V) and rapid response time (within 20 s) for stable and reproducible performance in long-term cycling. This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption, demonstrating great potential for aerospace, microelectronics, and energy conversion applications.
{"title":"Multifunctional rigid polyimide foams with outstanding EMI shielding and wave absorption via densification strategy","authors":"Yugen Wang, Jianwei Li, Yuanyuan Zhong, Jiahao Kang, Bilin Zhang, Zhonglei Ma, Qiangli Zhao","doi":"10.1016/j.jmst.2024.12.021","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.12.021","url":null,"abstract":"The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference (EMI) shielding and wave-absorbing materials. Hence, a densification strategy was proposed to fabricate multifunctional rigid polyimide (PI) composite foam. As a result, the composite PI foam exhibits excellent mechanical properties, with tensile and bending strengths of 4.7 and 21.1 MPa, respectively. Moreover, the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient (<em>A</em>) of 0.71, coupled with an X-band (8.2–12.4 GHz) EMI rating of 44 dB (2 mm) due to its high conductivity (20.29 ms/mm). Satisfyingly, the composite PI foam also has an optimal reflection loss (RL) of up to −46.4 dB and an effective absorption bandwidth (EAB) (RL < −10 dB) that covers the entire X-band. Meanwhile, the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages (3–9 V) and rapid response time (within 20 s) for stable and reproducible performance in long-term cycling. This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption, demonstrating great potential for aerospace, microelectronics, and energy conversion applications.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"54 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neuromorphic computing devices leveraging HfO2 and ZrO2 materials have recently garnered significant attention due to their potential for brain-inspired computing systems. In this study, we present a novel trilayer Pt/HfO2/ZrO2-x/HfO2/TiN memristor, engineered with a ZrO2-x oxygen vacancy reservoir (OVR) layer fabricated via radio frequency (RF) sputtering under controlled oxygen ambient. The incorporation of the ZrO2-x OVR layer enables enhanced resistive switching characteristics, including a high ON/OFF ratio (∼8000), excellent uniformity, robust data retention (>10⁵ s), and multilevel storage capabilities. Furthermore, the memristor demonstrates superior synaptic plasticity with linear long-term potentiation (LTP) and depression (LTD), achieving low non-linearity values of 1.36 (LTP) and 0.66 (LTD), and a recognition accuracy of 95.3% in an MNIST dataset simulation. The unique properties of the ZrO2-x layer, particularly its ability to act as a dynamic oxygen vacancy reservoir, significantly enhance synaptic performance by stabilizing oxygen vacancy migration. These findings establish the OVR-trilayer memristor as a promising candidate for future neuromorphic computing and high-performance memory applications.
{"title":"Enhanced synaptic properties in HfO2-based trilayer memristor by using ZrO2-x oxygen vacancy reservoir layer for neuromorphic computing","authors":"Turgun Boynazarov, Joonbong Lee, Hojin Lee, Sangwoo Lee, Hyunbin Chung, Dae Haa Ryu, Haider Abbas, Taekjib Choi","doi":"10.1016/j.jmst.2024.12.020","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.12.020","url":null,"abstract":"Neuromorphic computing devices leveraging HfO<sub>2</sub> and ZrO<sub>2</sub> materials have recently garnered significant attention due to their potential for brain-inspired computing systems. In this study, we present a novel trilayer Pt/HfO<sub>2</sub>/ZrO<sub>2-</sub><em><sub>x</sub></em>/HfO<sub>2</sub>/TiN memristor, engineered with a ZrO<sub>2-</sub><em><sub>x</sub></em> oxygen vacancy reservoir (OVR) layer fabricated via radio frequency (RF) sputtering under controlled oxygen ambient. The incorporation of the ZrO<sub>2-</sub><em><sub>x</sub></em> OVR layer enables enhanced resistive switching characteristics, including a high ON/OFF ratio (∼8000), excellent uniformity, robust data retention (>10⁵ s), and multilevel storage capabilities. Furthermore, the memristor demonstrates superior synaptic plasticity with linear long-term potentiation (LTP) and depression (LTD), achieving low non-linearity values of 1.36 (LTP) and 0.66 (LTD), and a recognition accuracy of 95.3% in an MNIST dataset simulation. The unique properties of the ZrO<sub>2-</sub><em><sub>x</sub></em> layer, particularly its ability to act as a dynamic oxygen vacancy reservoir, significantly enhance synaptic performance by stabilizing oxygen vacancy migration. These findings establish the OVR-trilayer memristor as a promising candidate for future neuromorphic computing and high-performance memory applications.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"7 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-15DOI: 10.1016/j.jmst.2024.11.066
Two novel out-of-plane ordered quaternary borides M’4VSiB2 (M’ = Nb and Mo) have been synthesized. The out-of-plane ordered characteristic has been co…
{"title":"Out-of-plane ordered quaternary borides M’4VSiB2 (M’ = Nb and Mo): Experimental and theoretical investigations","authors":"","doi":"10.1016/j.jmst.2024.11.066","DOIUrl":"https://doi.org/10.1016/j.jmst.2024.11.066","url":null,"abstract":"Two novel out-of-plane ordered quaternary borides M’4VSiB2 (M’ = Nb and Mo) have been synthesized. The out-of-plane ordered characteristic has been co…","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"54 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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