• Title, Summary, Keyword: Volume Fraction

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Effect of Deformation Induced Martensite on the Damping Capacity of Fe-26Mn-4Co-2Al Alloy (Fe-26Mn-4Co-2Al 합금의 감쇠능에 미치는 가공 유기 마르텐사이트의 영향)

  • Jeong, Kyu-Seong;Kang, Chang-Yong
    • Korean Journal of Materials Research
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    • v.26 no.9
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    • pp.493-497
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    • 2016
  • This study was carried out to investigate the effect of deformation induced martensite on the damping capacity of Fe-26Mn-4Co-2Al damping alloy. ${\alpha}^{\prime}$ and ${\varepsilon}$-martensite were formed by cold working, and; deformation induced martensite was formed with according to the specific direction and the surface relief. With an increasing degree of cold rolling, the volume fraction of ${\alpha}^{\prime}$-martensite increased rapidly, while the volume fraction of ${\varepsilon}$-martensite decreased after rising to a maximum value at a specific level of cold rolling. Damping capacity was increased, and then decreased with an increasing of the degree of cold rolling. Damping capacity was influenced greatly by the volume fraction of ${\varepsilon}$-martensite formed by cold working, but the effect of the volume fraction of ${\alpha}^{\prime}$-martensite have a actually on effect on the damping capacity.

Effect of Microstructure on the Characteristics of Fatigue Crack Propagation of Super Duplex Stainless Steel (수퍼 2상 스테인리스강의 피로균열진전 특성에 미치는 미세조직의 영향)

  • 도재윤
    • Journal of Ocean Engineering and Technology
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    • v.14 no.2
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    • pp.65-69
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    • 2000
  • This study is to investigate the characteristics of fatigue crack propagation in rolled super duplex stainless steel that was changed austenite-ferrite volume fraction by heat treatment. It was used two kinds of specimen the rolling and the transverse directions δ-phase fraction affected sound velocity hardness and Young's modulus. Characteristics of fatigue crack propagation was affected by anisotropy and (δ+γ) phase volume fractions.

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Improvement of Plastic Deformation in Hetrogeneous Atomic Cu-Zr Amorphous Alloy with Distributed Nanocrystals

  • Park, Jun-Young;Shibutani, Yoji;Wakeda, Masato
    • Proceedings of the KSME Conference
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    • pp.1718-1722
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    • 2008
  • This study explores the influence of volume fraction of nanocrystals of Cu-Zr amorphous alloys on shear band formation. As the number of crystals with very tiny size increases, the strain localization, i.e. shear band, decreases without large drop of flow stress. The DPRs also depict no sudden drop and relatively high values. The strain state during the deformation represents a few shear bands at low volume fraction while there are no distinguishable shear bands at high volume fraction of nanocrystals.

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An Experimental Study on the Engineering Properties of HPFRCC According to Kinds, Shapes and Volume Fraction of Fibers (섬유의 종류, 형상 및 치환율에 따른 HPFRCC의 공학적 특성에 관한 실험적 연구)

  • 김영덕;조봉석;김재환;김규용;최경렬;김무한
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.59-62
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    • 2003
  • Kinds, shapes and fraction ratios of fibers have influence on properties of HPFRCC(High-Performance Fiver Reinforced Cementitious Concrete ) like bending strength, strain capacity and fracture toughness. For example, hydrophilic fibers have different chemical bond strength from hydrophobic fibers, fiber shapes influence on fiber pull-out and rupture, and fiber volume fraction influence on bending strength. In this study, to estimate influences of kinds, shapes and fraction ratios of fibers, we make HFRCC with 3 kind of fiber in various volume fraction of fiber and compare cracking, bending strength and fracture toughness. As the results, bending strength of HPFRCC was increased as fiber volume fraction was Increase and fiber tensile strength was increase, and strain capacity and fracture toughness of HFRCC was higher in fiber pull-out fracture than in fiber rupture fracture. And HFRCC showing pseudo strain hardening has higher fiber reinforce efficiency than others.

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A Study on Strain-Void Growth Mechanism of Dual Phase Steel by Statistical Method (통계적 방법을 이용한 복합조직강의 변형률과 보이드 성장거동에 관한 연구)

  • 오경훈;유용석;오택열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.533-538
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    • 2000
  • Ductile fracture of dual phase steel begins with void nucleation, at martensite-ferrite interface of deformed martensite particle. In this study, void nucleation, growth, and coalescence under various strain were studied in dual phase steel. Therefore, by means of the heat treatment of low carbon steel, the study deals with void nucleation and growth for ferrite grain size and martensite volume fraction of dual phase steel using statistical method. Void nucleation and growth with increasing strain are shown depend upon the ferrite grain size. Voids volume fraction generally increase as ferrite grain size decease.

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The Preparation and Electrical Properties of 2-2 Type Piezocomposites (2-2형 압전복합재료의 제작 및 전기적 특성)

  • Lee, Sang-Wook;Go, Young-Jun;Nam, Hyo-Duk;Ryu, Jeong-Tak;Kim, Yeon-Bo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.146-149
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    • 2002
  • In this study, 2-2 type piezocomposites were made and characteristics as volume fraction of PZT were investigated. The accoustic impedance of 2-2 piezoelectric composites was linearly decreased with decreasing PZT volume fraction. when the volume fraction of PZT was 0.2 the acoustic impedance was 3.2 Mrayl. The electromechanical coupling factor was favourable in comparison with the single phase PZT, and that was about uniformed about 0.68 in the 0.2 to 0.6 of PZT volume fraction.

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Differential Molecular Diffusion Effects in $H_{2}-SF_{6}$ Mixture ($H_{2}-SF_{6}$ 혼합 기체 연료에서 분자 차등 확산 효과)

  • Oh, Kwang-Cheul;Choi, Jae-Joon;Shin, Hyun-Dong
    • 한국연소학회:학술대회논문집
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    • pp.16-25
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    • 2000
  • The differential diffusion of two species in jet is considered. The direct photo images of $H_{2}/SF_{6}$ flame are taken and the non-react jets of $H_{2}/SF_{6}$ mixture are visualized with Rayleigh scattering method. The structures of Dual flame are found in the photography. As the volume fraction of $H_2$ in mixture is increased, the flame at side is long and as the volume fraction of $SF_{6}$ in mixture is increased, the flame at center is long. This phenomena are deduced from the non-react mixture using Rayleigh scattering method. Result show that the volume fraction in the mixture is important in differential diffusion.

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A Study on Reduction of Thermal Interlaminar Forces of Fiber-Reinforced Laminate Composites Using Volume Fraction Gradient (체적비구배를 이용한 섬유강화 적층 복합재의 열하중에 의한 층건력 감소에 대한 연구)

  • Choe, Deok-Gi;Sin, Jong-Han
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.5
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    • pp.1115-1122
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    • 2000
  • This paper addresses an application of a fiber volume fraction gradients to reduce the interlaminar forces of fiber reinforced composites subjected to thermal loadings. The degree of the reduction in the interlaminar forces may be expressed by introducing a new parameter, so called, the interlaminar force parameter. Several cases of stacking sequences and models for fiber volume fraction gradients prove the availability of the new parameter which is defined in this study.

Study on the unidirectional compaction of terminal cables in the CICC joint

  • 남현일;이호진;박재학;홍계원
    • Progress in Superconductivity
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    • v.3 no.2
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    • pp.218-223
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    • 2002
  • The void volume fraction of cables is one of the effective parameters to characterize the joints of superconducting magnet. Because electrical resistance and cooling stability in the CICC (Cable-in-Conduit Conductors) joint are governed by the void volume fraction, it should be controlled constantly in the termination of cable. The change of cross-section shape in the cable was fecund during the unidirectional compaction of terminal sleeve. The non-uniform thickness of the sleeve after compaction is expected because the loading is not taxi-symmetric, and the plastic flow is also not axi-symmetric. The CICC was compacted from 45% void volume fraction to 15% by using two-piece compaction jig, which could be pressed mini-directionally. Commercial code, ABAQUS, was used to analyze the plastic flow in the sleeve during the unidirectional compaction. The increment of radius of curvature of compaction jig could minimize the change of the deformed shape of cables. The calculated results were agreed with the experimental observations.

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Effects on PZT volume fraction on the dielectric and piezoelectric properties with PZT/PVDF O-3 composites (PZT/PVDF O-3형 복합전체에 있어서 PZT 체적비 변화가 유전 및 압전특성에 미치는 영향)

  • 이덕출;김용혁
    • Electrical & Electronic Materials
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    • v.1 no.1
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    • pp.44-53
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    • 1988
  • In this study, PZT/PVDF composites with O-3 phase connectivity were prepared by hot pressing method, and the dielectric and piezoelectric properties as a function of PZT volume fraction were investigated. A modified cubic model was introduced to explain the influence of the PZT volume fraction on the experimentally determined dielectric constant. As A n=0.125, the measured dielectric constant values agreed with the calculated values. It was found that dielectric constant .xi.$_{33}$ and piezoelectric coefficient d$_{33}$ increased with indreasing PZT volume fraction, and hydrostatic piezoelectric figure of merit d/aub h/.g$_{h}$ was improved relative to that of the PZT single phase material.l.l.l.

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