• Title, Summary, Keyword: Dual Matrix Composites

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Interfacial Evaluation and Microfailure Mechanisms of Carbon Fiber/Bismaleimide (BMI) Composites using Tensile/compressive Fragmentation Tests and Acoustic Emission (인장/압축 Fragmentation 시험법과 음향방출을 이용한 Carbon Fiber/Bismaleimide (BMI) Composites 의 계면 평가와 미세파괴 메커니즘 연구)

  • 김진원;박종만;윤동진
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.79-83
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    • 2000
  • Interfacial and microfailure properties of carbon liber/bismaleimide (BMI) composites were evaluated using both tensile fragmentation and compressive Broutman tests with acoustic emission (AE). Since BMI is rather difficult matrix to apply for the conventional fragmentation test because of its too low elongation and too brittle and high modulus properties, dual matrix composite system was applied. After carbon fiber/BMI composite was prepared for rod shape by controlling differing curing stage, composites rod was embedded in toughened epoxy as outer matrix. The typical microfailure modes including fiber break, matrix cracking, and interlayer failure were observed during tensile testing, whereas the diagonal slippage in fiber ends was observed during compressive test. On the other hand, AE amplitudes of BMI matrix fracture were higher than carbon fiber tincture under tensile test because BMI matrix has very brittle and high modulus. The waveform of signals coming from BMI matrix fractures was consistent with AE amplitude result under tensile tests.

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The Thermal Shock Behaviors of Y-TZP/Y-TZP-Al2O3 Composites having Dual Microstructure (이중조직을 갖는 Y-TZP/Y-TZP-$Al_2O_3$ 복합체의 열충격 거동)

  • Hwang, K.H.;Kim, E.H.;Kim, Hwan
    • Journal of the Korean Ceramic Society
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    • v.29 no.4
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    • pp.283-292
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    • 1992
  • Duplex composites such as Y-TZP/Y-TZP-20 wt.% Al2O3 and Y-TZP/Y-TZP- 40 wt.% Al2O3 were made by mixing the sieve-shaked granules followed by isostatic pressing and sintering at 150$0^{\circ}C$ for 1 hour. So Y-TZP became matrix region and Y-TZP-20 wt.% Al2O3 or Y-TZP-40 wt.% Al2O3 became dispersed regions. In these composites, propagating cracks due to thermal shock always run into the dispersed region because these regions act as compressive zone due to low thermal expansion than matrix region. So duplexes having dispersed regions of Y-TZP-40 wt.% Al2O3 showed higher retained strength after thermal shock than matrix only composites because crack propagations were stopped more or less in the dispersed region. But when crack propagations were much more easy than matrix like Y-TZP-20 wt.% Al2O3 region, retained strength was decreased than the matrix only composites despite of the low initial strength.

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Nondestructive Evaluation and Microfailure Modes of Single Fibers/Cement Composites using Electro-Micromechanical Technique and Acoustic Emission (Electro-Micromechanical 시험법과 음향방출을 이용한 단섬유시멘트복합재료의 미세파괴구조와 비파괴적 평가)

  • Lee, Sang-Il;Kim, Jin-Won;Park, Joung-Man;Yoon, Dong-Jin
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.258-262
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    • 2001
  • The contact resistivity was correlated with IFSS and microfailure modes in conductive fiber/cement composites electro-pullout and AE. As IFSS increased, the number of AE signals increased and the contact resistivity increased latter to the infinity. In dual matrix composite (DMC) test and AE, the number of signals with high amplitude and energy in g]ass fiber composite is significantly larger than that of no-fiber composite. Many vertical and diagonal cracks were observed in glass fiber and no-fiber composite under tensile test, respectively. Electro-micromechanical technique and AE can be used efficiently for sensitive nondestructive (NDT) evaluation and to detect microfailure mechanisms in various conductive fibers reinforced brittle and nontransparent cement composites.

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Fabrication of Metallic Glass/metallic Glass Composites by Spark Plasma Sintering (방전플라즈마 소결법에 의한 비정질/비정질 복합재의 제조)

  • Lee, Jin-Kyu
    • Journal of Korean Powder Metallurgy Institute
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    • v.14 no.6
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    • pp.405-409
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    • 2007
  • The Cu-based bulk metallic glass (BMG) composites containing Zr-based metallic glass phase have been consolidated by spark plasma sintering using the mixture of Cu-based and Zr-based metallic glass powders in their overlapped supercooled liquid region. The Zr-based metallic glass phases are well distributed homogeneously in the Cu-based metallic glass matrix after consolidation process. The successful consolidation of BMG composites with dual amorphous phases was corresponding to the sound viscous flow of the two kinds of metallic glass powders in their overlapped supercooled liquid region.

Acoustically-enhanced particle dispersion in polystyrene/alumina nanocomposites

  • Philip, Mercy A.;Natarajan, Upendra;Nagarajan, Ramamurthy
    • Advances in nano research
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    • v.2 no.2
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    • pp.121-133
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    • 2014
  • Polymer nanocomposites are advanced nanomaterials which exhibit dramatic improvements in various mechanical, thermal and barrier properties as compared with the neat polymer. Polystyrene/ alumina nanocomposites were prepared by an ultrasound-assisted solution casting method at filler loadings ranging from 0.2 to 2% and also at different ultrasonic frequencies, viz. 58 kHz, 192/58 kHz, 430 kHz, 470 kHz and 1 MHz. The composites were subjected to mechanical property tests (tensile and impact tests) and cavitation erosion tests to study the enhancement in functional properties. Filler dispersion in the polymer matrix was observed by SEM analysis. The effect of frequency on filler dispersion in the matrix was studied by SEM analysis and functional property enhancement of the composite material. The composites prepared at dual (high/ low) frequency (192/58 kHz) were found to show better property enhancement at low filler loadings as compared with neat polymer and also with composites prepared without ultrasound, thus reinforcing the finding that ultrasound-assisted synthesis is a promising method for the synthesis of nanocomposites.

Microfailure Degradation Mechanisms and Interfacial Properties of Bioabsorbable Composites for Implant Materials using Micromechanical Technique and Acoustic Emission (Micromechanical 시험법과 음향방출을 이용한 Implant용 Bioabsorbable 복합재료의 미세파괴 분해메커니즘과 계면물성)

  • 박종만;김대식
    • Composites Research
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    • v.14 no.4
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    • pp.15-26
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    • 2001
  • Interfacial properties and microfailure degradation mechanisms of the bioabsorbable composites fur implant materials were investigated using micromechanical technique and nondestructive acoustic emission (AE). As hydrolysis time increased, the tensile strength, the modulus and the elongation of poly(ester-amide) (PEA) and bioactive glass fibers decreased, whereas these of chitosan fiber almost did not change. Interfacial shear strength (IFSS) between bioactive glass fiber and poly-L-lactide (PLLA) was much higher than PEA or chitosan fiber/PLLA systems using dual matrix composite (DMC) specimen. The decreasing rate of IFSS was the fastest in bioactive glass fiber/PLLA composites whereas that of chitosan fiber/PLLA composites was the slowest. AE amplitude and AE energy of PEA fiber decreased gradually, and their distributions became narrower than those in the initial state with hydrolysis time. In case of bioactive glass fiber, AE amplitude and AE energy in tensile failure were much higher than in compression. In addition, AE parameters at the initial state were much higher than those after degradation under both tensile and compressive tests. In this work, interfacial properties and microfailure degradation mechanisms can be important factors to control bioabsorbable composite performance.

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Plasma Treatment of Carbon Nanotubes and Interfacial Evaluation of CNT-Phenolic Composites by Acoustic Emission and Dual Matrix Techniques (음향 방출과 이중 기지 기술을 이용한 탄소나노튜브의 플라즈마 처리 효과에 따른 탄소나노튜브-페놀 복합재료의 계면특성 평가)

  • Wang, Zuo-Jia;Kwon, Dong-Jun;Gu, Ga-Young;Lee, Woo-Il;Park, Jong-Kyoo;Park, Joung-Man
    • Composites Research
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    • v.25 no.3
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    • pp.76-81
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    • 2012
  • Atmospheric pressure plasma treatment on carbon nanotube (CNT) surfaces was performed to modify reinforcement effect and interfacial adhesion of carbon fiber reinforced CNT-phenolic composites. The surface changes occurring on CNT treated with plasma were analyzed by using Fourier transform infrared spectroscope (FT-IR). The significant improvement of wettability on CNT was confirmed by static contact angle test after plasma treatment. Such plasma treatment resulted in a decrease in the advancing contact angle from $118^{\circ}$ to $60^{\circ}$. The interfacial adhesion between carbon fiber and CNT-phenolic composites increased by plasma treatment based on apparent modulus test results during quasi-static tensile strength. Furthermore, the proposed database offers valuable knowledge for evaluating interfacial shear strength (IFSS).

Single Fiber Composite(SFC) 시험법과 Acoustic Emission(AE)를 이용한 고분자 복합재료 계면전단강도 및 미세파손기구의 해석

  • 이준현;박종만;윤동진
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.656-659
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    • 1993
  • The failure phenomenon of Dual Basalt Fibers Reinforced Epoxy Composites(DFC) under tensile load was studied using acoustic emission(AE) technique. AE amplitude and AE energy were mainly associated with the internal microscopic failure mechanism of DFC specimen, such as fiber fracture, matrix cracking, and fiber/matrix debonding. Fiber failures in the DFC specimens were distinguishable by showing the highest AE energy amplitude. They were dependant on the fiber diameters. Matrix cracking was determined from the relatively lower AE amplitude and AE energy, whereas fiber/matrix debonding could not be successfully isolated. AE method, however, can be applicable to the fragmentation method for interfacial strength(IFSS) in DFC specimens with adjusting the threshold to isolate fiber breaks from matrix crack and debonding.

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A New Mixing Method of SiC Nanoparticle Reinforced Epoxy Composites with Large Concentration of SiC Nanoparticle (대용량 SiC 나노입자 강화 에폭시 복합재료의 새로운 분산방법)

  • Kwon, Dong-Jun;Shin, Pyeong-Su;Kim, Jong-Hyun;Park, Joung-Man
    • Composites Research
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    • v.29 no.4
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    • pp.223-229
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    • 2016
  • SiC nanoparticles were used to increase flexural properties of polymer matrix. This study was to manufacture huge concentration SiC nanoparticle/epoxy composites and to evaluate the dispersion. During mixing SiC nanoparticle and epoxy, 20 wt% SiC nanoparticle in total composites was used with both stirrer and sonication equipment together. Mixing speed and dispersion were improved with the method by using both stirrer and sonication equipment at the same time via mechanical test and FE-SEM. Based on the results, modeling of SiC nanoparticle dispersion could be established. Ultimately, unidirectional carbon fiber reinforced composites was manufactured using 20 wt% SiC nanoparticle/epoxy. Mechanical property of CFRP using dual stirrer and sonication mixing method was better than composites by single sonication mixing method.

A Study on the Interfacial Properties of Bioabsorbable Fibers/PoIy-L-Lactide Composites using Micromechanical Tests and Surface Wettability Measurement (Micromechanical 시험법과 표면 젖음성 측정을 이용한 생흡수성 섬유 강화 Poly-L-Lactide 복합재료의 계면물성 연구)

  • Park, Joung-Man;Kim, Dae-Sik;Kim, Sung-Ryong
    • Journal of Adhesion and Interface
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    • v.3 no.2
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    • pp.17-29
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    • 2002
  • Interfacial properties and microfailure degradation mechanisms of the bioabsorbable composites for implant materials were investigated using micromechanical technique and measurement of surface wettability. As hydrolysis time increased, the tensile strength, the modulus and the elongation of poly(ester-amide) (PEA) and bioactive glass fibers decreased, whereas those of chitosan fiber almost did not change. Interfacial shear strength (IFSS) between bioactive glass fiber and poly-L-lactide (PLLA) was much higher than PEA or chitosan fiber/PLLA systems using dual matrix composite (DMC) specimen. The decreasing rate of IFSS was the fastest in bioactive glass fiber/PLLA composites whereas that of chitosan fiber/PLLA composites was the slowest. Work of adhesion, $W_a$ between bioactive glass fiber and PLLA was the highest, and the wettability results were consistent with the IFSS. Interfacial properties and microfailure degradation mechanisms can be important factors to control bioabsorbable composite performance.

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