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Overview of acidic deep eutectic solvents on synthesis, properties and applications 预览
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作者 Hao Qin Xutao Hu +3 位作者 Jingwen Wang Hongye Cheng Lifang Chen Zhiwen Qi 《绿色能源与环境:英文版》 CSCD 2020年第1期8-21,共14页
This review divides the acidic deep eutectic solvents(ADES) into Br?nsted and Lewis DES according to their diversity of acidic character.The hydrogen bond donors and halide salts for formulating an ADES are classified... This review divides the acidic deep eutectic solvents(ADES) into Br?nsted and Lewis DES according to their diversity of acidic character.The hydrogen bond donors and halide salts for formulating an ADES are classified, the synthesis methods are described, and the physicochemical properties including freezing point, acidity, density, viscosity and conductivity are presented. Furthermore, the applications of Br?nsted acidic deep eutectic solvents(BADES) and Lewis acidic deep eutectic solvents(LADES) are overviewed, respectively, covering the fields in dissolution, extraction, organic reaction and metal electrodeposition. It is expected that the ADES has great potential to replace the pollutional mineral acid, expensive and unstable solid acid, and costly ionic liquid in many acid-employed chemical processes, thus meeting the demands of green chemistry. 展开更多
关键词 Acidic deep eutectic solvent Brønsted acidity Lewis acidity Green chemistry
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A356铝合金轮毂Si偏析现象及力学性能 预览
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作者 欧翅翔 汪樟锋 +2 位作者 刘锋睿 王孟君 陈柏辰 《有色金属科学与工程》 CAS 2020年第1期60-66,共7页
采用扫描电镜、金相显微和拉伸实验等分析了低压铸造A356轮毂的组织,建立了Si偏析现象的表征方法,并探讨了铸件SDAS值和Si颗粒平均面积对其力学性能的影响。结果表明:采用共晶面积分数、Si颗粒平均面积和长径比可以很好地表征Si偏析程度... 采用扫描电镜、金相显微和拉伸实验等分析了低压铸造A356轮毂的组织,建立了Si偏析现象的表征方法,并探讨了铸件SDAS值和Si颗粒平均面积对其力学性能的影响。结果表明:采用共晶面积分数、Si颗粒平均面积和长径比可以很好地表征Si偏析程度;轮毂轮辐中部R角处共晶面积分数、Si颗粒平均面积、长径比和SDAS值分别为34.83%、11.33μm2、2.46和56.89μm,相应的UTS、YS和EL值分别为229.02、152.67 MPa和5.34%,轮毂Si偏析程度越高的部位,其力学性能也越差。在分析铸件拉伸性能时,应综合考虑SDAS与Si偏析的影响。并且给出了解决Si偏析问题的具体措施。 展开更多
关键词 A356 铝合金轮毂 偏析 二次枝晶臂间距 共晶
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DNAN/PETN体系二元相图及低共熔物
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作者 刘晨丽 宋小兰 +2 位作者 黄浩 王毅 刘双 《装甲兵工程学院学报》 2019年第2期85-89,共5页
采用密度泛函理论研究了2,4—二硝基苯甲醚(DNAN)与季戊四醇四硝酸酯(PETN)的分子结构和分子间作用力,确定了低共熔物的分子结构,并根据不同物质的量之比混合体系的热分析数据,绘制了液化温度、熔融焓H与组分X的T-X和H-X相图,最后对低... 采用密度泛函理论研究了2,4—二硝基苯甲醚(DNAN)与季戊四醇四硝酸酯(PETN)的分子结构和分子间作用力,确定了低共熔物的分子结构,并根据不同物质的量之比混合体系的热分析数据,绘制了液化温度、熔融焓H与组分X的T-X和H-X相图,最后对低共熔物的机械感度进行了测试。结果表明:DNAN与PETN有形成稳定共聚物的潜能;由相图确定DNAN/PETN体系的最低共熔物组成为摩尔比80. 10/19. 90,该体系最低共熔温度为84. 94℃,比DNAN和PETN单质炸药熔点分别降低了8. 86、56. 06℃,此时特性落高H50=56 cm,90°摩擦感度P=0%,说明DNAN的存在降低了PETN的撞击感度和摩擦感度。 展开更多
关键词 低共熔物 密度泛函理论 热分解 二元相图
共晶贴片机精度影响因素研究 预览
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作者 赵雷 巨茗升 +1 位作者 曹国斌 侯一雪 《电子工艺技术》 2019年第4期230-232,共3页
GJJ-450全自动共晶贴片机是一款用于生产TO型半导体激光器的设备。±10μm的贴片精度和相比国外同领域设备较低的价格,使之成为国内激光器生产的主流设备。介绍了影响该设备精度的主要因素,即LD芯片焊接工位中涉及到的TO管座的贴合... GJJ-450全自动共晶贴片机是一款用于生产TO型半导体激光器的设备。±10μm的贴片精度和相比国外同领域设备较低的价格,使之成为国内激光器生产的主流设备。介绍了影响该设备精度的主要因素,即LD芯片焊接工位中涉及到的TO管座的贴合距离和X向对称度。验证了在不同贴合距离和X向对称度下,以贴装高度和水平偏差为衡量指标的设备的过程能力指数C pk。最后在此基础上提出改进措施,使设备使用者能够快速有效地完成调试和生产。 展开更多
关键词 TO激光器 共晶 精度 CPK
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钴基高温合金GH5605铸态组织及高温扩散退火过程中元素再分配
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作者 刘超 江河 +1 位作者 董建新 章清泉 《工程科学学报》 CSCD 北大核心 2019年第3期359-367,共9页
利用光学显微镜(OM)、场发射扫描电子显微镜(FESEM)、能谱分析(EDS)并结合热力学及动力学计算结果对采用真空感应熔炼和电渣重熔二联工艺生产的GH5605合金电渣锭的枝晶形貌、元素偏析和析出相进行分析.探索了合金的高温扩散退火制度并... 利用光学显微镜(OM)、场发射扫描电子显微镜(FESEM)、能谱分析(EDS)并结合热力学及动力学计算结果对采用真空感应熔炼和电渣重熔二联工艺生产的GH5605合金电渣锭的枝晶形貌、元素偏析和析出相进行分析.探索了合金的高温扩散退火制度并结合差示扫描量热仪(DSC)和热压缩模拟实验分析高温扩散退火前后的合金特征.结果表明:GH5605合金中的枝晶和元素偏析情况较轻,主要偏析元素是Cr和W并在枝晶间处偏聚,电渣锭中的主要析出相包括奥氏体、晶界M23C6以及晶内和晶界处的奥氏体与M23C6板条状共晶相.经1210℃/8 h扩散退火处理后枝晶和元素偏析基本消除,共晶相基本回溶. 展开更多
关键词 钴基高温合金 偏析 枝晶 共晶 高温扩散退火
Microstructure and Solid/liquid Interface Evolutions of Directionally Solidified Fe-Al-Ta Eutectic Alloy
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作者 崔春娟 WANG Songyuan +4 位作者 YANG Meng SU Haijun WEN Yagang WANG Pei REN Chiqiang 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2019年第3期656-661,共6页
A modified Bridgman directional solidification technique was used to prepare Fe-Al-Ta eutectic in situ composites at different growth rates ranging from 6 to 80 gm/s. The directionally solidified Fe- Al-Ta eutectic co... A modified Bridgman directional solidification technique was used to prepare Fe-Al-Ta eutectic in situ composites at different growth rates ranging from 6 to 80 gm/s. The directionally solidified Fe- Al-Ta eutectic composites are composed of two phases: Fe(Al,Ta) matrix phase, and Fe2Ta(Al) Laves phase. Solidification microstructure is affected by solidification rate. Microstructure of the Fe-Al-Ta eutectic alloy grown at 6.0 pm/s is broken-lamellar eutectic. Eutectic colonies are formed with the increase of the solidification rate. Microstructures are mainly composed of the lamellar or fibrous eutectic at the center of the colony and coarse lamellar eutectic zone at the boundary. Meanwhile, the inter-lamellar spacing (or the inter-rod spacing) is decreased. The spacing adjustments are also observed in Fe-Al-Ta eutectic alloy. The solid/liquid interface evolves from planar interface to shallow cellular interface, then to deep cellular, and finally to shallow cellular planar with the increase of the solidification rate. 展开更多
关键词 directional SOLIDIFICATION SOLIDIFICATION rate EUTECTIC alloy solid/liquid interface
Microstructure evolution and crystallography of directionally solidified Al2O3/Y 3 Al5O12 eutectic ceramics prepared by the modified Bridgman method
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作者 Xu Wang Nan Zhang +4 位作者 Yujie Zhong BailingJiang Langhong Lou Jian Zhang Jingyang Wang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第9期1982-1988,共7页
Large size,high-density(99.97%)and well-organized Al2O3/Y3Al5O12(YAG)eutectic ceramics were prepared by the modified Bridgman method.The evolution of the three dimensional microstructure and micropores were investigat... Large size,high-density(99.97%)and well-organized Al2O3/Y3Al5O12(YAG)eutectic ceramics were prepared by the modified Bridgman method.The evolution of the three dimensional microstructure and micropores were investigated.The diameter of the micro-pores and the porosity decreased during directional solidification.The average equivalent diam eter of the micro-pores was 2.41μm in the well-prepared eutectic ceramics.Most of the pores(98.07%)were smaller than 4μm.These data are comparable to those prepared by the optical floating zone method.The as-grown eutectic ceramics were polycrystalline,but the interfaces were well-bonded and there were no amorphous phases in the microstructure.The misfits of the different crystallographic relationships were calculated,and the bottleneck of the single-crystal preparation was identified.These results could provide theoretical guidance for the preparation of large,single-crystal Al2O3/YAG eutectic ceramics by the modified Bridgman method. 展开更多
关键词 Al2O3/YAG EUTECTIC CERAMICS CRYSTALLOGRAPHY Interfaces BRIDGMAN method
共熔法制备二硼化钛基复合材料的研究 预览
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作者 杨金华 刘占军 +1 位作者 郭全贵 焦健 《陶瓷学报》 CAS 北大核心 2019年第3期311-317,共7页
采用共熔法制备二硼化钛基复合材料,两组样品初始组份分别为TiB2、SiC及鳞片石墨,TiB2、TiC、SiC与鳞片石墨。研究表明,共熔法制备的复合材料中各相分散均匀,产物中的石墨高度有序,石墨层间距分别为0.3385 nm与0.3367 nm,且微晶厚度分别... 采用共熔法制备二硼化钛基复合材料,两组样品初始组份分别为TiB2、SiC及鳞片石墨,TiB2、TiC、SiC与鳞片石墨。研究表明,共熔法制备的复合材料中各相分散均匀,产物中的石墨高度有序,石墨层间距分别为0.3385 nm与0.3367 nm,且微晶厚度分别为60.8 nm及46.7 nm;拉曼光谱峰形及参数表明石墨的网格结构中掺杂有硼元素;TiB2基复合材料样品中孔隙率分别为12.5%与13.8%,热导率分别为41.0 W/(m K)与52.9 W/(m K)。 展开更多
关键词 二硼化钛 超高温陶瓷 陶瓷基复合材料 共熔
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共晶焊倒装高压LED的制备及性能分析 预览 被引量:1
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作者 尹越 田婷 +6 位作者 刘志强 王江华 伊晓燕 梁萌 闫建昌 王军喜 李晋闽 《照明工程学报》 2019年第1期26-31,共6页
使用共晶焊替代倒装焊,制备了由10颗LED微晶粒串联而成的共晶焊倒装高压LED。随后通过芯片外观对比及相关光电性能测试证实,共晶焊倒装高压LED在1W电注入下光功率相比倒装焊高压LED可提升10.5%,并且光效下降现象得到缓解。同时,ANSYS热... 使用共晶焊替代倒装焊,制备了由10颗LED微晶粒串联而成的共晶焊倒装高压LED。随后通过芯片外观对比及相关光电性能测试证实,共晶焊倒装高压LED在1W电注入下光功率相比倒装焊高压LED可提升10.5%,并且光效下降现象得到缓解。同时,ANSYS热模拟结果表明:共晶焊倒装结构芯片具有更好的散热特性,适合于大电流驱动。 展开更多
关键词 共晶焊 LED 高压 倒装结构 性能表征
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Application of deep eutectic solvents in biomass pretreatment and conversion 预览
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作者 Yu Chen Tiancheng Mu 《绿色能源与环境:英文版》 CSCD 2019年第2期95-115,共21页
Biomass is renewable,abundant,cheap,biocompatible,and biodegradable materials and has been used to produce chemicals,materials,energy,and fuels.However,most of the biomass,especially most of the biomass polymers are n... Biomass is renewable,abundant,cheap,biocompatible,and biodegradable materials and has been used to produce chemicals,materials,energy,and fuels.However,most of the biomass,especially most of the biomass polymers are not soluble in common solvents,which hinders their pretreatment and conversion.Deep eutectic solvents(DESs)are environmental-friendly,cheap,and highly tunable,with high solubility,which renders them potential applications in biomass pretreatment and conversion.They could be used as solvents or catalysts and so on.This paper intends to review the application of DESs for the pretreatment of biomass and conversion of biomass to value-added products.We focus on the following topics related to biomass and DESs:(1)DESs for the pretreatment of biomass;(2)DESs for the dissolution and separation of biomass or extraction of chemicals from biomass;(3)DESs for biomass conversion;(4)Drawbacks,and recyclability of DESs for pretreatment and conversion of biomass. 展开更多
关键词 DEEP EUTECTIC solvents BIOMASS PRETREATMENT CONVERSION
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New deep eutectic solvents composed of crown ether, hydroxide and polyethylene glycol for extraction of non-basic N-compounds
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作者 Mohammad Chand Ali Ruirui Liu +5 位作者 Jia Chen Tianpei Cai Haijuan Zhang Zhan Li Honglin Zhai Hongdeng Qiu 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第4期871-874,共4页
Here we firstly report a series of new deep eutectic solvents (DESs) induced by small amounts of crown ether complex and mainly formed by polyethylene glycol. These DESs not only presented the ultra-deep extraction of... Here we firstly report a series of new deep eutectic solvents (DESs) induced by small amounts of crown ether complex and mainly formed by polyethylene glycol. These DESs not only presented the ultra-deep extraction of non-basic N-compounds from fuel oils, but also opened up the possibility of other new applications in chemistry and materials science. 展开更多
关键词 Deep EUTECTIC solvents EXTRACTION Non-basic N-compounds Regeneration Selectivity
Deep eutectic ionic liquids based on DABCO-derived quaternary ammonium salts: A promising reaction medium in gaining access to terpyridines
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作者 Muhammad Faisal Azeem Haider +2 位作者 Quret ul Aein Aamer Saeed Fayaz Ali Larik 《化学科学与工程前沿:英文版》 EI CAS CSCD 2019年第3期586-598,共13页
Owing to the directional H-bonding,coordination and π-stacking abilities,terpyridines have been widely used as supramolecular tectons in molecular architectures,skeletons in molecular devices and metallopolymers,and ... Owing to the directional H-bonding,coordination and π-stacking abilities,terpyridines have been widely used as supramolecular tectons in molecular architectures,skeletons in molecular devices and metallopolymers,and are gaining importance in medicinal chemistry.In this paper,we have synthesized,characterized and applied deep eutectic ionic liquids (DEILs) based on 1,4-diazabicyclo[2.2.2]octane;triethylenediamine (DABCO)-derived quatemary ammonium salts for the preparation ofterpyridines.These DEILs were synthesized through N-alkylation of DABCO with haloalkanes (1-bromopentane or 1-bromoheptane) followed by mixing and heating with methanol or polyethylene glycol as a hydrogen bond donor.The synthesized DEILs were structurally characterized by IR and NMR.The formation of deep eutectic solvent was confirmed by freezing point depression,it composition was investigated through phase diagram,and its thermal stability was determined through differential scanning calorimetry,derivative thermogravimetry and thermal gravimetric analysis studies.Further,these DEILs were investigated for their effectiveness towards synthesis of 2,2':6',2"-terpyridine,3,2':6',3"-terpyridineand 4,2':6',4"-terpyridine derivatives through Kr(o)hnke reaction.The results show that these three types ofterpyridines can be obtained in reasonable yields (80%-97%) by the one-pot reaction of 2-,3-or 4-acetylpyridine with a variety of aromatic aldehydes in the presence of DEIL as a reaction medium,sodium hydroxide as a base and ammonium acetate as a cyclizing agent.This methodology is highly efficient and cost-effective for synthesis of symmetrical as well as unsymmetrical terpyridines.Importantly,these DEILs can be reused several times without an obvious loss of activity and are non-toxic,low-volatile,biodegradable and highly thermally stable.Therefore,these DEILs as a non-conventional reaction medium for the synthesis of terpyridines provides appealing opportunities to be investigated in the domain of green synthesis. 展开更多
关键词 TERPYRIDINE DEEP EUTECTIC SOLVENT IONIC liquid Krohnke reaction DABCO
Selective dissolution of rare-earth element carbonates in deep eutectic solvents
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作者 Ali Entezari-ZarANDi Fa??al Larachi 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2019年第5期528-533,共6页
Dissolution in choline-chloride based deep eutectic solvents(DES) of rare earth elements(REE) from high-purity single carbonate salts of Y, La, Ce, Nd and Sm and from their multicomponent mixtures and also bastn€asite... Dissolution in choline-chloride based deep eutectic solvents(DES) of rare earth elements(REE) from high-purity single carbonate salts of Y, La, Ce, Nd and Sm and from their multicomponent mixtures and also bastn€asite mineral was assessed with a prospect to gain an understanding on the leaching behavior of bastn€asite ores as REE source from DES suspensions. Urea, malonic acid and citric acid were used in different proportions with choline chloride in order to form deep eutectic solvents with desired viscosity and functionality. The results obtained prove promising for use insolvato-metallurgical processes in terms of selective dissolution of the higher-atomic-number(Z) rare earth elements at the expense of the lower-ZREEs and the gangue-originating metal impurities, thus initiating separation among the different REE members from the early hydrometallurgical steps. 展开更多
关键词 DEEP EUTECTIC SOLVENT IONIC liquid Bastn€asite Rare earth metals Solvato-metallurgy
Effects of electrode configuration on electroslag remelting process of M2 high-speed steel ingot
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作者 Fu-xing Yin Yu Liang +3 位作者 Zhi-xia Xiao Jian-hang Feng Zhi-bin Xie Yong-wang Mi 《中国铸造:英文版》 SCIE 2019年第2期126-134,共9页
The electrode configuration determines the thermophysical field during the electroslag remelting(ESR) process and affects the final microstructure of the ingot. In this work, ingot with a diameter of 400 mm was prepar... The electrode configuration determines the thermophysical field during the electroslag remelting(ESR) process and affects the final microstructure of the ingot. In this work, ingot with a diameter of 400 mm was prepared with two electrode configuration modes of single power ESR process, namely one electrode(OE) and two series-connected electrodes(TSCE). Finite element simulation was employed to calculate the electromagnetic field, flow field and temperature field of the ESR system. The results show that the temperature of the slag pool and the metal pool of the TSCE process is lower and more uniform than that of the OE process.The calculated temperature distribution of the ingot could be indirectly verified from the shape of the metal pool by the experiment. The experimental results show that the depth of the metal pool in the OE ingot is about 160 mm, while the depth of the TSCE ingot is nearly 40 mm shallower than that of the OE ingot. Microstructural comparisons indicate that coarse eutectic carbides are formed in the center of the OE ingot, whereas more even eutectic carbides appear in the center of the TSCE ingot. In general, compared with the OE process, the TSCE process is preferred to remelt high speed steel ingots. 展开更多
关键词 ELECTROSLAG REMELTING metal POOL shape electromagnetic field EUTECTIC carbides high SPEED steel
激光器芯片烧结用AuSn薄膜焊料制造技术研究 预览
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作者 刘凯 罗燕 +2 位作者 任卫鹏 王立春 彭斌 《电子元件与材料》 CAS CSCD 北大核心 2019年第8期106-110,共5页
共晶成分的金锡合金焊料AuSn20,具有较高的热导率、剪切强度、抗热疲劳性和抗腐蚀性,在高功率电子器件和光电子器件封装中应用广泛.本文在AlN陶瓷基板上,通过分层电镀Au/Sn/Au三层薄膜并合金化的方法,在AlN陶瓷表面制备了一种预制AuSn2... 共晶成分的金锡合金焊料AuSn20,具有较高的热导率、剪切强度、抗热疲劳性和抗腐蚀性,在高功率电子器件和光电子器件封装中应用广泛.本文在AlN陶瓷基板上,通过分层电镀Au/Sn/Au三层薄膜并合金化的方法,在AlN陶瓷表面制备了一种预制AuSn20合金焊料的基板.分析了焊料的成分及性能,结果满足国军标GJB 548B-2005《微电子器件试验方法和程序》的剪切强度要求.用该基板封装激光二极管后达到设计功率,光功率效率为35%. 展开更多
关键词 金锡 薄膜 分层电镀 共晶 合金化 激光二极管
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(准)共晶系相变储能材料的研究进展 预览
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作者 陈涛 孙寒雪 +1 位作者 朱照琪 李安 《化工进展》 EI CAS CSCD 北大核心 2019年第7期3265-3273,共9页
节能技术的发展是当今非常现实的问题,这些技术的发展方向之一是各行业的热能储存。相变储能材料由于其较大的潜热和恒温性,被广泛应用于潜热储能系统和热管理系统中。然而,单一相变材料的相变温度和潜热比较固定,难以同时满足多种储能... 节能技术的发展是当今非常现实的问题,这些技术的发展方向之一是各行业的热能储存。相变储能材料由于其较大的潜热和恒温性,被广泛应用于潜热储能系统和热管理系统中。然而,单一相变材料的相变温度和潜热比较固定,难以同时满足多种储能应用对各种潜热、相变温度等性质的要求。因此,人们开展了关于二元或多元共晶相变体系的研究。本文介绍了近年来国内外(准)共晶相变储能材料及其复合材料的研究进展,探讨了(准)共晶相变储能材料的理论设计机理,指出了(准)共晶相变储能材料存在的不同问题并提出建议,最后指出了(准)共晶系相变储能材料在实际应用领域的局限,提出未来在寻找新型相变储能材料,建立传热理论模型,对(准)共晶系复合相变储能材料的力学性能、耐老化性能、储能密度低和高温条件下的耐久性差等方面需要进一步探索。 展开更多
关键词 共晶 相变 相变材料 复合材料 理论设计 储能
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The interaction and migration of deformation twin in an eutectic high-entropy alloy AlCoCrFeNi2.1
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作者 Yaoli Zhang Jinguo Li +3 位作者 Xinguang Wang Yiping Lu Yizhou Zhou Xiaofeng Sun 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第5期902-906,共5页
An eutectic high-entropy alloy consisting Al, Co, Cr, Fe and Ni elements was prepared by vacuum directional solidification technology. The alloy exhibits excellent comprehensive mechanical performance during tension a... An eutectic high-entropy alloy consisting Al, Co, Cr, Fe and Ni elements was prepared by vacuum directional solidification technology. The alloy exhibits excellent comprehensive mechanical performance during tension at temperature range of 600–700℃. The microstructure reveals the intersection of twintwin is the prevailing deformation mechanism and the twins play a dual role in strengthening and toughening the alloy in the thermomechanical process. The deformation twin variants I and were formed by the edge dislocation 112 and the mixed dislocation 211 on the {111} crystal planes, respectively. Besides, the dislocation jogs and kinks caused by twin intersection on the slip planes can strengthen the alloy, which may contribute to the high strength(the tensile strengths at the 600°and 700°tensile tests are respectively780 MPa and 630 MPa.). Moreover, the coherent twin boundary migration has the function of coordinating deformation and contributes to the high ductility of the alloy. 展开更多
关键词 EUTECTIC high-entropy alloy TENSILE properties Deformation TWIN DISLOCATION jog TWIN MIGRATION
Microstructural evaluation and mechanical properties of 7075 aluminum alloy prepared by controlled diffusion solidification
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作者 Xiong Yang Yuan-dong Li +4 位作者 Xiao-mei Luo Hong-wei Zhou Qi-yong Cai Ming Li Ying Ma 《中国铸造:英文版》 SCIE 2019年第4期238-247,共10页
In the present work, 7075 aluminum alloy(Al-Zn-Mg-Cu) was produced by both conventional casting(CC) and controlled diffusion solidification(CDS) methods. Each sample was subjected to different heat-treatment condition... In the present work, 7075 aluminum alloy(Al-Zn-Mg-Cu) was produced by both conventional casting(CC) and controlled diffusion solidification(CDS) methods. Each sample was subjected to different heat-treatment conditions: as-cast, T4, and T6;and their microstructural and mechanical properties were investigated by optical microscopy(OM), scanning electron microscopy(SEM) and X-ray diffractometry(XRD). It was found that CDS promoted the formation of non-dendritic primary α-Al phase and reduced shrinkage porosity, thus resulting in improved mechanical properties. In addition, the eutectic phase of the CDS samples mainly consisted of T(Al-ZnMg-Cu) phase, which manifested a well-developed lamellar eutectic structure. However, in the CC samples, the T(Al-Zn-Mg-Cu) phase was composed of rod-like eutectics. Moreover, the θ(Al2 Cu) eutectic contents in the CC samples were greater than those in the CDS samples. Each element in the CC samples had an obvious change in the grain boundary, whereas the change in element content in the CDS samples was gradual. Therefore, the non-dendritic morphology of the primary phase and the presence of rod-like eutectics in the matrix of the CDS samples led to enhanced tensile strength and elongation under different heat treatment conditions. 展开更多
关键词 primary α-Al PHASE EUTECTIC PHASE SOLUTE ATOMS tensile strength ELONGATION
Effect of Ca addition on solidification microstructure of hypoeutectic Al-Si casting alloys
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作者 Xiang-yi Jiao Chao-feng Liu +5 位作者 Jun Wang Zhi-peng Guo Jun-you Wang Zhuo-ming Wang Jun-ming Gao Shou-mei Xiong 《中国铸造:英文版》 SCIE 2019年第3期153-160,共8页
The effect of Ca addition on the solidification microstructure of hypoeutectic Al-Si casting alloys was investigated using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) methods with pa... The effect of Ca addition on the solidification microstructure of hypoeutectic Al-Si casting alloys was investigated using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) methods with particular attention focused on the change of morphologies of primary α-Al and eutectic silicon. Meanwhile,solute distribution in solid-liquid was simulated according to Scheil-Gulliver law. Results showed that primary α-Al and eutectic silicon were refined as Ca content increased because of the variation of the solute concentration in liquid. The addition of Ca increased the nucleation sites like Al3Ti or Al2Cu to promote the nucleation of primary α-Al. Affected by modification effect of Ca, the shape of eutectic silicon changed from flake to fibrous structure. In addition, coarse plate Ca-rich phases could be found along the grain boundary with high Ca content. 展开更多
关键词 Ca ADDITION PRIMARY α-Al EUTECTIC silicon REFINEMENT
Eutectic mixture promoted CO2 sorption on MgO-TiO2 composite at elevated temperature
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作者 Vishwanath Hiremath Monica Louise T.Trivino Jeong Gil Seo 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第2期80-88,共9页
The development of carbon dioxide (CO2) sorbents that can operate at elevated temperatures is significant for the advancement of pre-combustion capture technologies. Recently, promoter-based systems composed of alkali... The development of carbon dioxide (CO2) sorbents that can operate at elevated temperatures is significant for the advancement of pre-combustion capture technologies. Recently, promoter-based systems composed of alkali/alkaline earth metal nitrates and/or carbonates have been considered as next-generation solid sorbents due to their improved CO2 uptake and kinetics. However, obtaining stable MgO sorbents against temperature swing regeneration still remained challenging. Herein, we report MgO-TiO2 solid sorbents promoted by eutectic mixture (KNO3 and LiNO3) for elevated temperature CO2 sorption. The developed sorbents show improved CO2 sorption capacity, which may be attributed to the alternative CO2 sorption pathway provided by the ionization of highly dispersed MgO in the eutectic mixture. The MgO-TiO2 framework was also shown to assist in retaining the MgO configuration by constraining its interaction with CO2. Furthermore, it is demonstrated that constructing composite structures is essential to improve the CO2 sorption characteristics, mainly recyclability, at elevated temperatures. The developed promoter integrated sorbents showed exceptionally high CO2 sorption capacity of > 30 wt.% at an elevated temperature (300°C) with pronounced stability under temperature swing operation. 展开更多
关键词 MgO-TiO2 COMPOSITE Elevated temperature CO2 capture EUTECTIC mixture promoter MGO stability
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