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Bio-Based Hyperbranched Toughener From Tannic Acid and Its Enhanced Solvent-Free Epoxy Resin with High Performance 被引量:6
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作者 Jie Xu Jiayao Yang +5 位作者 Hengxu Wang Peng Lin Xiaohuan Liu Jinjie Zhang Shenyuan Fu Yuxun Tang 《Journal of Renewable Materials》 SCIE 2019年第12期1333-1346,共14页
It is essential to design economic and efficient tougheners to prepare high-performance epoxy resin;however,this has remained a huge challenge.Herein,an eco-friendly,low-cost,and facile-fabricated bio-based hyperbranc... It is essential to design economic and efficient tougheners to prepare high-performance epoxy resin;however,this has remained a huge challenge.Herein,an eco-friendly,low-cost,and facile-fabricated bio-based hyperbranched toughener,carboxylic acid-functionalized tannic acid(CATA),was successfully prepared and applicated to the preparation of solvent-free epoxy resins.The mechanical performance,morphology,structural characterization,and thermal characterization of toughened epoxy resin system were studied.The toughened epoxy resin system with only 1.0wt%CATA reached the highest impact strength,111%higher than the neat epoxy resin system.Notably,the tensile strength and elongation at break of toughened epoxy resin systems increased moderately with increasing CATA loading.Nonphase-separated hybrids with significant toughening effect were obtained.Additionally,the thermal stabilities of toughened epoxy resin systems decreased with increasing CATA loading.This study provides an eco-friendly,cost-effective,and facile approach for the preparation of high-performance,solvent-free epoxy resins with potential for practical applications in sealing integrated circuits and electrical devices fields. 展开更多
关键词 Solvent-free epoxy resins bio-based toughener bio-based curing agent mechanical performance thermal properties
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Preparation and Performance of Short Carbon Fiber and Flake Graphene Reinforced Polycarbonate Composites: Effects of Different Tougheners 被引量:2
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作者 Zhixing Yu Yu Bai +2 位作者 Yingcheng Li Wei Wang James H. Wang 《Journal of Materials Science and Chemical Engineering》 2018年第7期81-89,共9页
Different tougheners including methyl methacrylate-butadiene-styrene terpolymer (MBS, core-shell type), maleic anhydride (MAH) grafted ethylene-octene copolymer (EOM), and MAH grafted polyethylene wax (PEM) were inves... Different tougheners including methyl methacrylate-butadiene-styrene terpolymer (MBS, core-shell type), maleic anhydride (MAH) grafted ethylene-octene copolymer (EOM), and MAH grafted polyethylene wax (PEM) were investigated for toughening the polycarbonate (PC) composites reinforced by short carbon fiber (SCF) and flake graphene (FG). The effects of tougheners on the preparation, thermal conductivity and mechanical properties of PC composites were studied. Scanning electron microscopy was used for characterizing the impact fracture surfaces of the composites. The results showed that introducing tougheners into the carbon reinforced PC composites was beneficial to improving the processability, and PEM was more effective than EOM and MBS. Meanwhile, the through-thickness and the in-plan thermal conductivity decreased to some degree due to the isolated island effects of tougheners. Moreover, the brittle PC composites with high flexural stress could be easily toughened by tougheners. In contrast, PEM had better toughening function than EOM and MBS, and correspondingly, the stiffness of the composites was the lowest for the PEM toughened systems. The fractography revealed that dense and uniformly distributed carbon fillers dispersed in matrix PC and circular cavities coexisted in the composites. The naked fiber length gradually increased as the ductility of composite materials improved. 展开更多
关键词 toughener PROCESSABILITY Thermal CONDUCTIVITY Mechanical Property FRACTOGRAPHY
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Influence of Different Tougheners on the Properties of PC/PBT Alloy
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作者 Pengwei Shi Junjie Tang Hao Duan 《Journal of Materials Science and Chemical Engineering》 2021年第11期70-82,共13页
This paper focuses on the influence of glycidyl methacrylate functionalized polyolefin elastomer (SOG-03) on the properties of PC/PBT alloys, and also made a contrastive analysis with ethylene-methyl acrylate-glycidyl... This paper focuses on the influence of glycidyl methacrylate functionalized polyolefin elastomer (SOG-03) on the properties of PC/PBT alloys, and also made a contrastive analysis with ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA-co-GMA) and methyl methacrylate-butadiene-styrene terpolymer (MBS), the common toughener in PC/PBT alloy. The impact performance test results of PC/PBT alloys with different addition of SOG-03 showed that the brittle-ductile transition began when SOG-03 content reached 3 wt%. The microstructure, differential scanning calorimeter (DSC) and multi-extrusion process results of PC/PBT alloys all showed that SOG-03 tends to be dispersed in PBT phase and the dispersed SOG-03 presents typical rubber-toughened polymer morphology. The toughening efficiency of MBS on PC/PBT alloy was much lower than EMA-co-GMA and SOG-03, and showed a worse processing stability after multi-extrusion process and long-term thermal ageing properties. The EMA-co-GMA and SOG-03 toughened PC/PBT alloys showed an equivalent toughness, while the PC/PBT alloy with SOG-03 showed a better processing stability during the multi-extrusion process and long-term thermal ageing property when the thermal aging time is more than 600 h. 展开更多
关键词 PC/PBT Alloy toughener MICROSTRUCTURE Thermal Stability Processing Stability
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MoS_(2)Lubricate‑Toughened MXene/ANF Composites for Multifunctional Electromagnetic Interference Shielding
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作者 Jiaen Wang Wei Ming +8 位作者 Longfu Chen Tianliang Song Moxi Yele Hao Zhang Long Yang Gegen Sarula Benliang Liang Luting Yan Guangsheng Wang 《Nano-Micro Letters》 SCIE EI CAS 2025年第2期358-371,共14页
The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem.Ternary MXene/ANF(ar... The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem.Ternary MXene/ANF(aramid nanofibers)–MoS_(2)composite films with nacre-like layered structure here are fabricated after the introduction of MoS_(2)into binary MXene/ANF composite system.The introduction of MoS_(2)fulfills an impressive“kill three birds with one stone”improvement effect:lubrication toughening mechanical performance,reduction in secondary reflection pollution of electromagnetic wave,and improvement in the performance of photothermal conversion.After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 50:50),the strain to failure and tensile strength increase from 22.1±1.7%and 105.7±6.4 MPa and to 25.8±0.7%and 167.3±9.1 MPa,respectively.The toughness elevates from 13.0±4.1 to 26.3±0.8 MJ m^(−3)(~102.3%)simultaneously.And the reflection shielding effectiveness(SE_(R))of MXene/ANF(mass ratio of 50:50)decreases~10.8%.EMI shielding effectiveness(EMI SE)elevates to 41.0 dB(8.2–12.4 GHz);After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 60:40),the strain to failure increases from 18.3±1.9%to 28.1±0.7%(~53.5%),the SE_(R)decreases~22.2%,and the corresponding EMI SE is 43.9 dB.The MoS_(2)also leads to a more efficient photothermal conversion performance(~45 to~55℃).Additionally,MXene/ANF–MoS_(2)composite films exhibit excellent electric heating performance,quick temperature elevation(15 s),excellent cycle stability(2,2.5,and 3 V),and long-term stability(2520 s).Combining with excellent mechanical performance with high MXene content,electric heating performance,and photothermal conversion performance,EMI shielding ternary MXene/ANF–MoS_(2)composite films could be applied in many industrial areas.This work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers. 展开更多
关键词 MXene-MoS_(2) Lubrication toughening EMI shielding Photothermal conversion Electric heating performance
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SYNTHESIS OF A HYPERBRANCHED POLYETHER EPOXY THROUGH ONE- STEP PROTON TRANSFER POLYMERIZATION AND ITS APPLICATION AS A TOUGHENER FOR EPOXY RESIN DGEBA 被引量:4
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作者 李效玉 王海侨 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2012年第4期493-502,共10页
A novel liquid hyperbranched polyether epoxy (HBPEE) based on commercially available hydroquinone (HQ) and 1,1,1-trihydroxymethylpropane triglycidyl ether (TMPGE) was synthesized through an A2 + B3 one-step pro... A novel liquid hyperbranched polyether epoxy (HBPEE) based on commercially available hydroquinone (HQ) and 1,1,1-trihydroxymethylpropane triglycidyl ether (TMPGE) was synthesized through an A2 + B3 one-step proton transfer polymerization. In order to improve the toughness, the synthesized HBPEE was mixed with diglycidyl ether of bisphenol A (DGEBA) in different ratios to form hybrids and cured with triethylenetetramine (TETA). Thermal and mechanical properties of the cured hybrids were evaluated. Results show that addition of HBPEE can improve the toughness of cured hybrids remarkably at 〈 20 wt% loading, without compromising the tensile strength. However, the glass transition temperature (Tg) of the cured hybrids decreases with increasing HBPEE content. Fracture surface images from scanning electron microscope show oriented fibrils in hybrids containing HBPEE. The formation and orientation of the fibrils can absorb energy under impact and lead to an improvement of toughness. Furthermore, based on the morphology of fractured surfaces and the single Tg in each hybrid, no sign of phase separation was found in the cured hybrid systems. As a result, the toughening mechanism could be explained by in situ homogeneous toughening mechanism rather than phase separation mechanism. 展开更多
关键词 HYPERBRANCHED EPOXY POLYETHER TOUGHENING Proton transfer polymerization.
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Improving the ductility and toughness of nano-TiC/AZ61 composite by optimizing bimodal grain microstructure via extrusion speed
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作者 Lingling Fan Mingyang Zhou +5 位作者 Wulve Lao Yuwenxi Zhang Hajo Dieringa Ying Zeng Yuanding Huang Gaofeng Quan 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第8期3264-3280,共17页
In this study,the nano-TiC/AZ61 composites with different heterogeneous bimodal grain(HBG)structures and uniform structure are obtained by regulating the extrusion speed.The effect of HBG structure on the mechanical p... In this study,the nano-TiC/AZ61 composites with different heterogeneous bimodal grain(HBG)structures and uniform structure are obtained by regulating the extrusion speed.The effect of HBG structure on the mechanical properties of the composites is investigated.The increasing ductility and toughening mechanism of HBG magnesium matrix composites are carefully discussed.When the extrusion speed increases from 0.75 mm/s to 2.5 mm/s or 3.5 mm/s,the microstructure transforms from uniform to HBG structure.Compared with Uniform-0.75 mm/s composite,Heterogeneous-3.5 mm/s composite achieves a 116.7%increase in ductility in the plastic deformation stage and almost no reduction in ultimate tensile strength.This is mainly because the lower plastic deformation inhomogeneity and higher strain hardening due to hetero-deformation induced(HDI)hardening.Moreover,Heterogeneous-3.5 mm/s composite achieves a 108.3%increase in toughness compared with the Uniform-0.75 mm/s composite.It is mainly because coarse grain(CG)bands can capture and blunt cracks,thereby increasing the energy dissipation for crack propagation and improving toughness.In addition,the CG band of the Heterogeneous-3.5 mm/s composite with larger grain size and lower dislocation density is more conducive to obtaining higher strain hardening and superior blunting crack capability.Thus,the increased ductility and toughness of the Heterogeneous-3.5 mm/s composite is more significant than that Heterogeneous-2.5 mm/s composite. 展开更多
关键词 Nano-TiC/AZ61 composite Extrusion speed Heterogeneous bimodal grain structure Increasing ductility mechanism Toughening mechanism
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Progress in Research on Structural Ceramic Materials Toughened by Graphene
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作者 Wenyu Yao Yalong Zhang 《Expert Review of Chinese Chemical》 2024年第2期37-42,共6页
Graphene has excellent mechanical properties and unique physical/chemical properties,which make it have a good strengthening and toughening effect on structural ceramic materials.In recent years,it has received widesp... Graphene has excellent mechanical properties and unique physical/chemical properties,which make it have a good strengthening and toughening effect on structural ceramic materials.In recent years,it has received widespread attention and research.This article reviews the mixing and sintering processes in the preparation of graphene/ceramic com-posites,as well as the toughening mechanism of graphene on ceramic materials.It also looks forward to how to further enhance the toughening effect of graphene. 展开更多
关键词 GRAPHENE CERAMICS mixing materials SINTERING TOUGHENING
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Mechanical properties of calcium carbonate whisker-reinforced high-strength cement mortar 被引量:4
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作者 张聪 曹明莉 《Journal of Southeast University(English Edition)》 EI CAS 2012年第3期331-336,共6页
In order to improve the brittleness of high-strength cement mortar,calcium carbonate(CaCO3) whiskers are incorporated to strengthen and toughen the high-strength cement mortar.The compressive strength,flexural stren... In order to improve the brittleness of high-strength cement mortar,calcium carbonate(CaCO3) whiskers are incorporated to strengthen and toughen the high-strength cement mortar.The compressive strength,flexural strength,split tensile strength and work of fracture are measured.Microstructures and micromechanical behaviors are investigated using scanning electron microscopy.The strengthening and toughening mechanisms and the efficiency of whisker-reinforced high-strength cement mortar are discussed.The results show that the addition of CaCO3 whiskers brings positive effects on the high-strength cement mortar.The strengthening and toughening mechanisms are whisker-cement coalition debonding,whisker peeling,whisker impact breakage and whisker bridging.Crack deflection is one efficient mechanism,but it is hard to be achieved in high-strength cement mortar.And the interfacial bonding strength between whiskers and the cement mortar matrix should be appropriately weak to introduce more crack deflection mechanisms to strengthen and toughen the cement mortar efficiently. 展开更多
关键词 high-strength mortar CaCO3 whisker strengthen-ing TOUGHENING
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Special epoxy silicone adhesive for inertial confinement fusion experiment 被引量:3
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作者 李芝华 李波 郑子樵 《Journal of Central South University of Technology》 EI 2007年第2期153-156,共4页
The effects of toughener and coupling agent on special epoxy silicone adhesive were discussed by researching the surface morphology characters, thermal properties and shear strength of the adhesive. The results indica... The effects of toughener and coupling agent on special epoxy silicone adhesive were discussed by researching the surface morphology characters, thermal properties and shear strength of the adhesive. The results indicate that silicone coupling agent (KH-550) can improve the shear strength of the epoxy silicone adhesive effectively. The mass fraction of the toughener in the epoxy silicone adhesive plays an important role in its properties. When the mass fraction of the toughener is less than 14%, the shear strength of the adhesive is low. When the mass fraction of the toughener is over 33%, thermal properties and shear strength of the adhesive decrease with the increasing of the toughener. The mass fraction of toughener of 25% results in good integral properties of the epoxy silicone adhesive. The morphologic analysis indicates that the micro-phase separation exists in the epoxy molecular chain and the silicone molecular chain of the epoxy silicone adhesive. 展开更多
关键词 inertial confinement fusion experiment epoxy silicone toughener coupling agent micro-phase separation
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MICROSTRUCTURE AND MECHANICAL PROPERTIES OF SiC_W/BAS (BaAl_2Si _2O_8) GLASS-CERAMIC COMPOSITE 被引量:14
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作者 J.M.Yang,J.C.Lei,J.P.Li and P.Cheng Dept. Mater.Sci.and Eng. Xi’an Institute of Technology, Xi’an 710032,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1999年第5期1130-1135,共6页
BAS (BaAl 2Si 2O 8) glass ceramic was prepared by a sol gel process and the SiC W/BAS composites were fabricated by hot pressing. The transformation from hexacelsian to celsian, the microstructure and mechanical prope... BAS (BaAl 2Si 2O 8) glass ceramic was prepared by a sol gel process and the SiC W/BAS composites were fabricated by hot pressing. The transformation from hexacelsian to celsian, the microstructure and mechanical properties of the composites was investigated. The results show that the transformation promoted by adding celsian seeds is retarded in the composite by the presence of SiC whisker. SiC whisker has a good effect of improving the mechanical properties of BAS glass ceramic matrix. The toughening mechanisms are crack deflection and whisker fracture. The strengthening mechanism is loading transition. The amorphous phase at SiC W/BAS matrix interface damages the fracture toughness and high temperature strength of the composites. 展开更多
关键词 GLASS CERAMIC CELSIAN composite TOUGHENING strengthening
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Microstructure-fracture toughness relationships and toughening mechanism of TC21 titanium alloy with lamellar microstructure 被引量:15
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作者 Zhi-feng SHI Hong-zhen GUO +1 位作者 Jian-wei ZHANG Jian-ning YIN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第12期2440-2448,共9页
The independent influence of microstructural features on fracture toughness of TC21alloy with lamellar microstructure was investigated.Triple heat treatments were designed to obtain lamellar microstructures with diffe... The independent influence of microstructural features on fracture toughness of TC21alloy with lamellar microstructure was investigated.Triple heat treatments were designed to obtain lamellar microstructures with different parameters,which were characterized by OM and SEM.The size and content ofαplates were mainly determined by cooling rate from singleβphase field and solution temperature in two-phase field;while the precipitation behavior of secondaryαplatelets was dominantly controlled by aging temperature in two-phase field.The content and thickness ofαplates and the thickness of secondaryαplatelets were important microstructural features influencing the fracture toughness.Both increasing the content ofαplates and thickeningαplates(or secondaryαplatelets)could enhance the fracture toughness of TC21alloy.Based on energy consumption by the plastic zone of crack tip inαplates,a toughening mechanism for titanium alloys was proposed. 展开更多
关键词 titanium alloy lamellar microstructure fracture toughness crack tip plastic zone toughening mechanism
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Effects of material of metallic frame on the penetration resistances of ceramic-metal hybrid structures 被引量:7
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作者 Xuanyi An Chao Tian +1 位作者 Qitian Sun Yongxiang Dong 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第1期77-87,共11页
The effects of metallic material on the penetration resistances of ceramic-metal hybrid structures against vertical long-rod tungsten projectiles were studied by artillery-launched experiments and numerical simulation... The effects of metallic material on the penetration resistances of ceramic-metal hybrid structures against vertical long-rod tungsten projectiles were studied by artillery-launched experiments and numerical simulation.Hybrid structures with rectangular cores in transverse orthogonal arrangement and slidefitting ceramic inserts of zirconia toughened alumina prisms were fabricated with titanium alloy TC4(Ti6 Al4 V),AISI 4340 steel and 7075 aluminum alloy panels,respectively.The results showed that the hybrid structure of Ti6A14V exhibited the highest penetration resistance,followed by that of 7075 aluminum alloy with the same area density.The penetration resistance of the hybrid structure of AISI4340 steel was the lowest.The underlying mechanisms showed that the metallic material of a ceramicmetal hybrid structure can directly affect its energy absorption from the impact projectile,which further affects its penetration resistance.Different metallic frames exhibited different failure characteristics,resulting in different constraint conditions or support conditions for ceramic prisms.The high penetration resistance of the Ti6Al4V hybrid structure was due to its stronger back support to ceramic prisms as compared with that of AISI 4340 steel hybrid structure,and better constraint condition for ceramic prisms by metallic webs as compared with that of 7075 aluminum alloy hybrid structure.The results of mass efficiency and thickness efficiency showed that the Ti6Al4V hybrid structure has advantages in reducing both the thickness and the mass of protective structure.In addition,because the ceramic-metal hybrid structures in the present work were heterogeneous,impact position has slight influence on their penetration resistances. 展开更多
关键词 Hybrid structures ZIRCONIA toughened alumina PENETRATION resistance Long-rod PROJECTILE METALLIC FRAME
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EFFECT OF TRIAXIAL STRESS CONSTRAINT ON THE DEFORMATION AND FRACTURE OF POLYMERS 被引量:6
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作者 王铁军 Kikno Kishimoto Mitsuo Notomi 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2002年第5期480-493,共14页
One purpose of this paper is to give a brief overview on the research status of deformation,fracture and toughening mechanisms of polymers,including experimental,theoretical and numerical studies.Emphasis is on the mo... One purpose of this paper is to give a brief overview on the research status of deformation,fracture and toughening mechanisms of polymers,including experimental,theoretical and numerical studies.Emphasis is on the more recent progresses of micromechanics of rubber particle cavitation and crazing,and the de- velopment of fracture criteria for ductile polymers. The other purpose is to study the effect of triaxial stress constraint on the deforma- tion and fracture behavior of polymers.Polycarbonate(PC),acrylonitrile-butadiene- styrene(ABS)and PC/ABS alloy are considered in this investigation.A series of circumferentially blunt-notched bars are used to experimentally generate different tri- axial stress fields.The fracture surfaces of specimens with different notch radius are examined by scanning electron microscope(SEM)to study the fracture and tough- ening mechanisms of polymer alloy.It is shown that the triaxial stress constraint has a significant effect on the deformation,fracture and toughening of PC,ABS and PC/ABS alloy.We will also discuss the extent to which a micromechanies criterion proposed by the first author can serve as a fracture criterion for ductile polymers. A new ductile fracture parameter is emphasized,which can be employed to evaluate the fracture ductility of polymers.Stress state independence of the parameter for the PC,ABS and PC/ABS alloy has been experimentally verified. 展开更多
关键词 deformation FRACTURE TOUGHENING CAVITATION crazev MICROMECHANICS PC ABS polymer alloy
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Microstructure and Mechanical Properties of CaCO_3 Whisker-reinforced Cement 被引量:11
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作者 曹明莉 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第5期1004-1009,共6页
Composite Portland cement (PC) played an important role in various kinds of construction engineering owing to low hydration heat,low-cost,and application of solid industrial waste,but its brittleness and low strengt... Composite Portland cement (PC) played an important role in various kinds of construction engineering owing to low hydration heat,low-cost,and application of solid industrial waste,but its brittleness and low strength limited its use in stress-bearing locations.The aim of this study is to improve the toughness and fracture resistance by incorporating CaCO3 whisker in cement matrix.Effect of different content of calcium carbonate whiskers on the mechanical properties of PC was investigated.The results showed that the flexural strength,impact strength and split tensile strength were increased by 39.7%,39.25% and 36.34% at maximum,respectively.Microstructure and elements of the whiskers in hardened cement were observed and analyzed by SEM/EDS.The mechanisms of the reinforcement of CaCO3 whisker on cement were also discussed,and the conclusion was that the improvement could be correlated to energy-dissipating processes owing to crack bridging,crack deflection,and whisker pull-out at the crack tips. 展开更多
关键词 CaCO3 whiskers reinforcement composite Portland cement mechanical properties microstructure toughening mechanism
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A Review on Binderless Tungsten Carbide: Development and Application 被引量:12
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作者 Jialin Sun Jun Zhao +7 位作者 Zhifu Huang Ke Yan Xuehui Shen Jiandong Xing Yimin Gao Yongxin Jian Hejie Yang Bo Li 《Nano-Micro Letters》 SCIE EI CAS CSCD 2020年第1期158-194,共37页
WC-Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades.Despite the advantages,however,recently there have been concerns about the challenges associated with ... WC-Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades.Despite the advantages,however,recently there have been concerns about the challenges associated with the use of Co,i.e.price instability,toxicity and properties degeneration,which necessitates the fabrication of binderless tungsten carbide(BTC).On the other hand,BTC or BTC composites,none of them,to date has been commercialized and produced on an industrial scale,but only used to a limited extent for specialized applications,such as mechanical seals undergoing high burthen as well as high temperature electrical contacts.There are two challenges in developing BTC:fully densifying the sintered body together with achieving a high toughness.Thus,this review applies towards comprehensively summarize the current knowledge of sintering behavior,microstructure,and mechanical properties of BTC,highlighting the densification improving strategies as well as toughening methods,so as to provide reference for those who would like to enhance the performance of BTC with better reliability advancing them to further wide applications and prepare the material in a way that is environment friendly,harmless to human health and low in production cost.This paper shows that the fabrication of highly dense and high-performance BTC is economically and technically feasible.The properties of BTC can be tailored by judiciously selecting the chemical composition coupled with taking into careful account the effects of processing techniques and parameters. 展开更多
关键词 Binderless tungsten carbide SINTERING DENSIFICATION TOUGHENING Mechanical properties
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Toughening mechanism of lined Al_2O_3-ZrO_2 multiphaseceramics in SHS composite pipes 被引量:11
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作者 Guibo Yu Wen Yan Shuhai Wang Baoxin Su Baolai Tan 《Journal of University of Science and Technology Beijing》 CSCD 2006年第2期178-182,共5页
Hypoeutectic and hypereutectic Al2O3-ZrO2 multiphase ceramics-lined composite pipes were produced by using the gravitational separation self-propagate high-temperature synthesis (SHS) process. The microstructure of ... Hypoeutectic and hypereutectic Al2O3-ZrO2 multiphase ceramics-lined composite pipes were produced by using the gravitational separation self-propagate high-temperature synthesis (SHS) process. The microstructure of the ceramics was observed by means of SEM and EPMA. The fracture toughness of the multiphase ceramics was tested by using the Vickers indentation method. The fracture toughness of hypoeutectic Al2O3-ZrO2 multiphase ceramics is 15.96 MPa·m^1/2 and that of hypoeutectic Al2O3-ZrO2 multiphase ceramics is 15.23 MPa·m^1/2. The toughening mechanisms were systematically investigated by means of SEM and XRD. The results show that the bridging toughening mechanism, stress induced ZrO2 transformation toughening mechanism, and microcrack toughening mechanism are the predominant toughening mechanism. 展开更多
关键词 SHS multiphase ceramics eutectic structure toughening mechanism
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SPECIAL EFFECT OF ULTRA-FINE RUBBER PARTICLES ON PLASTIC TOUGHENING 被引量:7
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作者 乔金樑 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2002年第2期93-98,共6页
According to the present theories of plastic toughening, it is impossible to enhance the toughness, stiffness and/orheat resistance of plastics simultaneously by using rubber. A series of novel nano-rubber particles (... According to the present theories of plastic toughening, it is impossible to enhance the toughness, stiffness and/orheat resistance of plastics simultaneously by using rubber. A series of novel nano-rubber particles (UFPR) were introduced,which were prepared through irradiating common rubber lattices and spray drying them. Epoxies toughened with UFPRshowed a much better toughening effect than those with CTBN, and the heat resistance of epoxy was unexpectedly elevated.For polypropylene toughening, UFPR can improve the toughness, stiffness and heat resistance of PP simultaneously. Thesespecial toughening effects overcome the deficiencies in rubber toughening technology and are worth further investigating. 展开更多
关键词 powdered rubber NANO-PARTICLES TOUGHENING POLYPROPYLENE epoxy resin
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DESIGN AND PREPARATION OF SILICON NITRIDE COMPOSITE WITH HIGH FRACTURE TOUGHNESS AND NACRE STRUCTURE 被引量:12
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作者 Y Huang H.N Hao Y.L. Chen and B.L.Zhou (1)Department of Materials Science and Engineering, Tsinghua University,Beijing 100084, China 2)Institute of Metal Research, Chinese Academy of Sciences,Shenyang 110015, China ) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1996年第6期479-484,共6页
A new way of designing and preparing silicon nitride ceramic composite with high fracture toughness and nacre structure has been proposed. To mimic the laminated structure of nacre, Si_3N_4 matrix ceramic layer can be... A new way of designing and preparing silicon nitride ceramic composite with high fracture toughness and nacre structure has been proposed. To mimic the laminated structure of nacre, Si_3N_4 matrix ceramic layer can be obtained through compacting rolling method. To mimic the secondary toughening of nacre structure, SiC whisker is added into Si_3N_4 and acts as the secondary toughening phase. Boron nitride (BN)is selected to mimic the organic layer in nacre so as to form the weak interfaces between Si_3N_4 layers. Alumina is added into BN to adjust the bonding strength of the interface.The Si_3N_4 sheets are stacked into the die after coating with BN. After the removal of the organic matter in them, the green body is hot pressed at 1820℃for 1.5 hours under N_2 atmosphere. The fracture toughness of the so-made Si_3N_4 composite at room temperature is 20.36MPa m ̄(1/2), the three-point bending strength at room temperature is 651.47MPa. The crack spreads and deflects along the interface between BN and Si_3N_4 layer and extends through the BN layer into Si_3N_4 layer. The improvement of the fracture toughness may be due to the staircase-shape-like crack which provides the long crack path, the fracture and deformation of Si_3N_4 layer, and the pullout of SiC whiskers from the Si_3N_4 layer. 展开更多
关键词 secondary toughening compact rolling silicon nitride nacre Structure
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Mechanical Properties and Microstructure of CaSO4 Whisker Reinforced Cement Mortar 被引量:4
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作者 WAN Lianjian PAN Ruizhi 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第5期1170-1176,共7页
Calcium sulfate whisker(CaSO4 whiskers), a new type of microfiber material, was used in cement matrix to increase the strength of the cement based composites. Effect of CaSO4 whiskers on the mechanical properties of t... Calcium sulfate whisker(CaSO4 whiskers), a new type of microfiber material, was used in cement matrix to increase the strength of the cement based composites. Effect of CaSO4 whiskers on the mechanical properties of the resulting cement mortar was also studied. The results showed that the flexural strength and compressive strength of the mortar specimen was improved as high as 28.3% and 8.5% by incorporating 5 wt% CaSO4 whiskers. Also, the chemical composition and structural transformation of the hardened cement matrix with CaSO4 whiskers were identified by X-ray diffraction(XRD) and scanning electron microscope(SEM). Conclusion can be drawn that CaSO4 whiskers can effectively retard the formation and restrict the coalescence of micro-crack expansion. The interaction mechanism of CaSO4 whisker on the reinforcement is mainly on three aspects: whisker pullout, crack deflection, and crack bridging. Mercury intrusion porosimetry(MIP) tests have confirmed that for 28 d cement mortar, the harmless pores increased from 9.33% to 10.62%, and the harmful pores decreased from 2.08% to 1.90%. Therefore, the whisker can optimize the pore size distribution of the resulting cement mortar. 展开更多
关键词 calcium SULFATE WHISKER reinforcement mechanical properties MICROSTRUCTURE TOUGHENING mechanism cement PASTE
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Room-temperature mechanical properties of WSi_2/MoSi_2 composites 被引量:5
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作者 ZHANGHouan LIUXinyu 《Rare Metals》 SCIE EI CAS CSCD 2002年第4期304-307,共4页
Five kinds of WSi_2/MoSi_2 composites were successfully prepared bymechanical alloying, IP and high temperature sintering techniques. And their hardness and fracturetoughness were measured by the Vickers indentation f... Five kinds of WSi_2/MoSi_2 composites were successfully prepared bymechanical alloying, IP and high temperature sintering techniques. And their hardness and fracturetoughness were measured by the Vickers indentation fracture mode through an Hv-10A type sclerometer.The microstructure and morphology were investigated by a JSM-56001V scanning electron microscope.Results show that the addition of 50% WSi_2 (in mole fraction) has remarkable hardening andtoughening effects on the MoSi_2 matrix, whose hardness value and fracture toughness value areincreased about 60% and 86%, respectively. For WSi_2/MoSi_2 composite, the hardening mechanisms arefine-grain and the second phase particles strengthening, and the toughening mechanisms includefine-grain, grain drawing, crack deflection, microbridge and bowing toughening. 展开更多
关键词 MoSi_2 WSi_2 hardening and toughening mechanical property
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