• Title, Summary, Keyword: Tensile properties

Search Result 5,378, Processing Time 0.046 seconds

Measurement of Micro-Tensile Properties using ESPI technique (ESPI 기법을 이용한 미소 인장 특성 추정)

  • Huh, Yong-Hak;Kim, Dong-Il;Yoon, Kyung-Jin;Kim, Koung-Suk;Oh, Chung-Seog
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.18 no.5
    • /
    • pp.90-97
    • /
    • 2001
  • An electronic speckle pattern interferometry (ESPI) system for measuring tensile properties under micro-tensile testing has been developed. The system consists of an optical system and an image processing system. In the optical system, optical components for measurement of in-plane deformation are arranged on the path of He-Ne laser. In the image processing system, the window-based program for acquiring speckle pattern interferometric image was developed and deformation in a small specimen is continuously evaluated during the test. Using this system, tensile strain of copper foil was measured during tensile testing. Tensile specimen had the thickness and width of 22 and 500 ${\mu}{\textrm}{m}$, respectively. Tensile properties, including the elastic modulus, yielding strength and tensile strength, of the copper were evaluated and also plastic exponent and coefficient in the Ramberg-Osgood relationship were evaluated from the stress-strain curve.

  • PDF

Evaluation of the Tensile Properties of Fuel Cladding at High Temperatures Using a Ring Specimen (링 시험편을 이용한 피복관의 고온 인장특성 평가)

  • Bae Bong-Kook;Koo Jae-Mean;Seok Chang-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.29 no.4
    • /
    • pp.600-605
    • /
    • 2005
  • In this study, the ring tensile test at high temperature was suggested to evaluate the hoop tensile properties of small tube such as the cladding in the nuclear reactor Using the Arsene's ring model, the ring tensile test was performed and the test data were calibrated. From the result of the ring test with strain gauge and the numerical analysis with 1/8 model, LCRR(load-displacement conversion relationship of ring specimen) was determined. We could obtain the hoop tensile properties by means of applying the LCRR to the calibrated data of the ring tensile test. A few difference was observed in view of the shape of fractured surface and the fracture mechanism between at the high temperature and at the room temperature.

Elevated Temperature Tensile Properties of Austempered Ductile Irom (Mo-Ni-Cu계 오스템퍼 구상흑연주철의 고온특성)

  • Yi, Young-Sang;Kang, In-Chan
    • Journal of Korea Foundry Society
    • /
    • v.11 no.4
    • /
    • pp.323-330
    • /
    • 1991
  • The relationships between the microstructure changes, retained austenite volume and elevated temperature tensile properties of Mo-Ni-Cu ADI corresponding to various austempering temperatures and time were investigated, After the $250^{\circ}C$ tensile test for the test piece austempered at $270^{\circ}C$ the accicular bainite structure was observed blunted under room temperature microscope. In the case of $370^{\circ}C$ austempering, the feathery bainite lath spacing was observed broadened. But after the $450^{\circ}C$ tensile test, bainitic features could not be observed. As the testing temperature increased, retained austenite volume tested at room temperature decreased. Especially, after the $450^{\circ}C$ tensile test retained austenite volume approached nearly to zero. A little higher tensile properties appeared at $250^{\circ}C$ testing than those at room temperature.

  • PDF

Effect of Mold Materials on the Microstructure and Tensile Properties of Al-Si based Lost Foam Casting Alloy (Al-Si계 소실모형주조합금의 미세조직 및 인장성질에 미치는 주형재료의 영향)

  • Kim, Jeong-Min;Lee, Gang-Rae;Choe, Kyeong-Hwan
    • Journal of Korea Foundry Society
    • /
    • v.39 no.5
    • /
    • pp.87-93
    • /
    • 2019
  • The effects of mold materials on the microstructure and tensile properties were investigated to develop a mass production technique of aluminum alloy parts with excellent mechanical properties using a lost foam casting method. The microstructures of the plate-shaped cast alloy showed a tendency to be finer in proportion to the thickness of the plate, and a remarkably fine structure was obtained by applying a steel chill or a ball as a mold material compared to general sand. When a steel ball was used, it was observed that the larger the ball, the finer the cast structure and the better the tensile properties. The microstructure and tensile properties of the cast parts with complex shapes were greatly affected by the gating system, but the positive effects of the steel chill and the steel ball as a mold material were clear.

Microstructure and Mechanical Properties of AZ91 Magnesium Alloy Containing a Small Amount of Sn (미량 Sn을 함유한 AZ91 마그네슘 합금의 미세조직 및 기계적 특성)

  • Jun, Joong-Hwan
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.27 no.3
    • /
    • pp.115-120
    • /
    • 2014
  • Microstructural features were comparatively investigated in AZ91 (Mg-9%Al-1%Zn) and AZ91-0.5%Sn alloys, in order to clarify the reason for the enhancement in room temperature tensile properties by the addition of small amount of Sn in Mg-Al-based alloy. In as-cast state, the Sn-containing alloy showed increased YS, UTS and elongation than the Sn-free alloy. The microstructural examination revealed that various factors including finer cell size, reduction of lamellar (${\alpha}+{\beta}$) phase and morphological change of bulky ${\beta}$ phase from partially divorced shape to fully divorced shape, are likely to be responsible for the improvement in tensile properties for the Sn-containing alloy. It is noted that two alloys showed similar tensile properties after solution treatment. This implies that microstructural evolution related to the ${\beta}$ phase plays a key role in better tensile properties in the Sn-containing alloy.

Effects of Surface Roughness and Microstructure on Tensile Properties of As-Casted Ni-Al Bronze (Ni-Al 청동 주물의 인장 특성에 미치는 표면 조도 및 미세 조직의 영향)

  • Park, Tae-Dong;Kim, Dae-Young
    • Journal of Korea Foundry Society
    • /
    • v.20 no.5
    • /
    • pp.316-322
    • /
    • 2000
  • Effect of surface roughness and microstructure of the specimen on tensile properties of Ni-Al bronze casting has been investigated. surface roughnesses of the tensile test specimen of interest are in range of 0.1 to 2.0 ${\mu}m$ in Ra obtained by changing machining conditions. Fracture of the Ni-Al bronze casting initiated at the surface and propagated in a brittle manner during tensile tests. Tensile elongation value of the casting was strongly dependent on the surface roughness range studied, while tensile and yield strengths were almost independent on it. The elongation value was almost constant up to the surface roughness of 1.0 ${\mu}m$ in Ra, and then decreased in a linear manner with an increase in Ra value up to 2.0 ${\mu}m$. However, tensile strength and hardness were strongly dependent on the microstructure, especially ${\alpha}$ phase fraction, and were decreased with increasing ${\alpha}$ phase fraction in microstructure. It is, therefore, recommended that decrease of surface roughness up to 1.0 ${\mu}m$ in Ra, shrinkage porosity and ${\alpha}$ phase are required in order to obtain good tensile properties for Ni-Al bronze casting.

  • PDF

A Study on the Tensile Properties of Polyester Warp Knitted Fabrics (폴리에스테르 경편포의 신장특성에 관한 연구)

  • 김석근;최재우;남은우
    • Textile Coloration and Finishing
    • /
    • v.12 no.1
    • /
    • pp.17-24
    • /
    • 2000
  • The tensile properties of polyester warp knitted fabrics of satin and reverse satin structure with various lengths of underlap were studied. In the range of low tension, the satin warp knitted fabric showed larger tensile energy and elongation in the direction of $0^\circ$ and larger tensile linearity, tensile resilience and initial modulus in $90^\circ$. Meanwhile, reverse satin one showed larger initial moduli in 0$^{\circ}$ and larger the others in $90^\circ$. In the range of high tension, the tendencies of both fabrics in $0^\circ$ direction were almost the same as those in all direction. As the under laps were shorter for both fabrics, tensile linearity, tensile energy and elongation increased, but tensile resilience decreased in all directions. However initial moduli were changed little.

  • PDF

Polymerization and Optical Properties of Polymers with High Tensile Strength Added Isocyanate Group

  • Sung, A-Young;Ye, Ki-Hun
    • Journal of the Chosun Natural Science
    • /
    • v.6 no.1
    • /
    • pp.1-7
    • /
    • 2013
  • Polyurethane resin containing isocyanate is marked by excellent tensile and mechanical strengths and this test aims to gauge its applicability as a medical high polymer. Tris [2-(acryloyloxy)ethyl]isocyanurate and hexamethylenediisocyanate were added to a basic mixing ratio of HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), NVP (n-vinyl-2-pyrrolidone) and crosslink agent, EGDMA (ethylene glycol dimethacrylate) with increasing proportions and copolymerized respectively. Also, the basic physical properties of the polymerized high polymers including refraction rate, tensile strength, light transmission and water content were measured to confirm that they are appropriate as hydrogelcontact lenses. After measuring the physical properties of high performance polymers produced by adding tris [2-(acryloyloxy) ethyl]isocyanurate, it was found that the average tensile strengths of sample TRIS1 to TRIS10 were between 0.285 and 0.612 kgf, while the average values of refractive index were ranged from 1.441 to 1.449 with water content from 30.00 to 37.35%.The measurement of physical properties of the copolymers generated by adding hexamethylenediisocyanate showed that the average tensile strength of sample HEXA1 to HEXA10 ranged from 0.267 to 1.742 kgf, the refractive index ranged from 1.443 to 1.475 and water contents were in the range of 21.22 to 35.58%. In all combinations the transmission rates satisfied the transmittance of general hydrogel contact lenses. From theresults, it is possible to conclude that the produced copolymers can be used as contact lens materials with excellent tensile strength.

Effect of Austenitizing and Quenching·Tempering Temperatures on Tensile and Impact Properties of AISI 51B20 (AISI 51B20강의 인장 및 충격특성에 미치는 오스테나이트화 온도와 퀜칭·템퍼링 온도의 영향)

  • Kim, Heon-Joo
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.24 no.6
    • /
    • pp.327-337
    • /
    • 2011
  • Effects of microstructural change, tensile properties and impact property according to the change of austenitizing temperature and tempering temperature of AISI 51B20 steel were examined. Regardless of austenite grain size, lath martensite with needle and packet shapes was found at tempering temperature of $300^{\circ}C{\sim}400^{\circ}C$. The needles of lath martensite changed to parallel packet at tempering temperature of $450^{\circ}C{\sim}600^{\circ}C$. As tempering temperature increased, tensile strength, yield strength and hardness decreased, while elongation, ratio of reduction area and Charpy impact energy increased. Grain size increased when quenching temperature was $930^{\circ}C$. Grain size had prominent effect on the mechanical properties of AISI 51B20 steel. Ratio of tensile strength/yield strength and yield strength autenitized at $880^{\circ}C$ followed by tempering at $350^{\circ}C{\sim}450^{\circ}C$ showed higher values than that of autenization at $930^{\circ}C$ due to fine grain size.

Creep & Tensile Properties of Thermally Grown Alumina Films (열 생성 알루미나 박막의 크리프 및 인장 특성)

  • Ko, Gyoung-Dek;Sun, Shin-Kyu;Kang, Ki-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.31 no.6
    • /
    • pp.665-670
    • /
    • 2007
  • Alpha-phase alumina TGO(Thermally Grown Oxide) forms on the interface between zirconia top coat and bond coat of thermal barrier coating system for superalloys during exposure to high temperature over $1000^{\circ}C$. It is known to provide a good protection against hot corrosion and to cause surface failure such as rumpling and cracking due to difference in thermal expansion coefficient from the substrate metal and the lateral growth. Consequently, mechanical properties of the alumina TGO at the high temperature are the key parameters determining the integrity of TBC system. In this work, by using Fecralloy foils as the alumina forming substrate, creep tests and tensile tests have been performed with various TGO thicknesses$(h=0{\sim}4{\mu}m)$ and yttrium contents(0, 200ppm) at $1200^{\circ}C$. Displacement-time curves and load-displacement curves for each TGO thickness(h=1,2,..) were measured from the creep and tensile tests, respectively, and compared with the curves without TGO thickness(h=0). As the result, the intrinsic tensile and creep properties of TGO itself were determined.