• 제목/요약/키워드: annealing temperatures

검색결과 734건 처리시간 0.025초

NITINOL 형상기억합금의 열적/기계적 특성 평가 (Evaluation of Thermomechanical Characteristics of NITINOL Shape Memory Alloy)

  • 윤성호
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2001년도 춘계학술대회 논문집
    • /
    • pp.683-686
    • /
    • 2001
  • The thermomechanical characteristics of NITINOL shape memory alloy were evaluated using DSC with small samples and DMA with three-point bending specimens. The shape memory alloy of 54.4Ni/45.5Ti wt.% was used so that the austenite finish temperature was in the range of $50~100^{\circ}C$. Two types of sample were tested in the experiments corresponding to as-received and annealed conditions. Simple beam bending theory was used to calculate the dynamic moduli of the shape memory alloy. According to the results, a large discrepancy in transformation temperatures was found between DSC and DMA techniques. Annealing treatment was found to suppress the R-phase transformation during cooling and the secondary plateau in the austenite transformation. Such a heat treatment was also significantly influenced to raise the transformation temperatures and the moduli of the shape memory alloy.

  • PDF

Ni-Ti 형상기억합금의 상변환 거동 연구 (Phase Transformation Behaviors of Ni-Ti shape memory Alloys)

  • 조보;오진오;윤성호
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2006년도 춘계학술대회 논문집
    • /
    • pp.87-88
    • /
    • 2006
  • The phase transformation behaviors of Ni-Ti shape memory alloys were investigated through a DSC(Differential Scanning Calorimetry). The annealing temperatures were applied from $600^{\circ}C,\;700^{\circ}C,\;800^{\circ}C,\;and\;900^{\circ}C$ for their effects on the phase transformation behaviors. Based on the results of DSC, phase transformation behaviors of shape memory alloys can be predicted by Liang's phase transformation model or Tanaka's phase transformation model.

  • PDF

정수압 압출 소재의 열처리 조건에 따른 마그네슘합금(AZ31)의 특성 변화 (Characteristics of Extruded Mg alloy(AZ31) for various annealing temperatures)

  • 서영원;최호준;윤덕재
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2005년도 추계학술대회 논문집
    • /
    • pp.463-466
    • /
    • 2005
  • Restoring ductility or removing residual stresses is a necessary operation when a large amount of cold working is to be performed, such as in a cold-forging or warm forging process. The advantage of annealing temperatures was investigated. After Hydrostatic Extrusion process, extruded materials were annealed at $200^{\circ}C,\;350^{\circ}C,\;450^{\circ}C$ for 1 hour. Microstructure of the annealed material was observed to make an understand about the difference in mechanical properties.

  • PDF

Structural and Optical Properties of CdS Thin Films Deposited by R.F. Magnetron Sputtering

  • 황동현;안정훈;손영국
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
    • /
    • pp.149-149
    • /
    • 2011
  • CdS films were deposited on glass substrates by R.F. magnetron sputtering method and the films were annealed at various substrate temperatures ranging from room temperature to $300^{\circ}C$. Structural properties of the films were studied by X-ray diffraction analysis. The structural parameters as crystallite size have been evaluated. The crystallite sizes were found to increase, and the X-ray diffraction patterns were seen to sharpen by increasing substrate temperatures. X-ray diffraction patterns of these films indicated that they contain both cubic (zincblende) and hexagonal (wurtzite) structures as a mixture. Optical properties of the films were measured at room temperature by using UV/VIS spectrometer in the wavelength range of 190 to 1100nm and optical absorption coefficients were calculated using these data. The energy gap of the films was found to decrease, and the band edge sharpness of the optical absorption was seen to oscillate by annealing. The results show that heat treatments under optimal annealing condition can provide significant improvements in the properties of CdS thin films.

  • PDF

Selection of RAPD Markers for Phytophthora infestans and PCR Detection of Phytophthora infestans from Potatoes

  • Kim, Kyung-Su;Lee, Youn-Su
    • Journal of Microbiology
    • /
    • 제39권2호
    • /
    • pp.126-132
    • /
    • 2001
  • For rapid and secure differentiation of P. infestans from other Phytophthora species, two fragments obtained from randomly amplified polymorphic DNA (RAPD) profiles were selected as markers. Also, primers for in polymerase chain reaction (PCR) to detect P. infestans specifically were developed by analyzing the sequences of ITSII regions in rDNA of Phytophthora species. The primers, PISP-1 and ITS3 amplified a single. Fragment 450 bp of about in P. infestans, but not in other fungal or bacterial isolates. Annealing temperatures and template DNA quantities were varied for the optimization of PCR conditions. From the result of the PCR detection study, species-specific primers were selected under annealing temperatures ranging from 55$^{\circ}C$ to 61$^{\circ}C$, and template DNA levels ranging from 10 pg to 100 ng.

  • PDF

펄스레이저 증착법으로 성장된 ZnO 박막의 어닐링 온도변화에 따른 구조적, 광학적 특성에 관한 연구 (Annealing Effect on the structural and optical properties of ZnO thin films prepared by Pulsed Laser Deposition)

  • 김재홍;이천
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
    • /
    • pp.54-57
    • /
    • 2004
  • ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition(PLD) technique using an Nd:YAG laser with a wavelength of 266 m. During deposition, the experiment of the deposition of ZnO thin films has been performed for substrate temperatures in the range of $400^{\circ}C$ and flow rate of 350 sccm, films have been annealed at various substrate temperatures after deposition. After post-annealing treatment in the oxygen ambient, the structural properties of ZnO thin films were characterized by diffraction (XRD), SEM and the optical of the ZnO were characterized by photoluminescence (PL).

  • PDF

AZ31 판재에서 소둔처리가 상온성형성에 미치는 영향 (Effect of Annealing Treatment on Cold Formability of AZ31 Sheets)

  • 황범규;이영선;문영훈;김대용
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2009년도 추계학술대회 논문집
    • /
    • pp.395-398
    • /
    • 2009
  • The purpose of this paper is to investigate the effect of annealing treatment on cold formability of magnesium alloy sheet AZ31. The AZ31 sheets with three different thickness (1.0t, 1.6t, 2.0t) were annealed at three different temperatures ($345^{\circ}C$, $400^{\circ}C$ and $450^{\circ}C$). The mechanical properties and microstructure evolution of the annealed AZ31 were examined as well as limit dome height (LDH) and compared with those of as received one. The cold formability was enhanced but the strength was deteriorated by the annealing treatment.

  • PDF

Optimized Local Relocation for VLSI Circuit Modification Using Mean-Field Annealing

  • Karimi, Gholam Reza;Verki, Ahmad Azizi;Mirzakuchaki, Sattar
    • ETRI Journal
    • /
    • 제32권6호
    • /
    • pp.932-939
    • /
    • 2010
  • In this paper, a fast migration method is proposed. Our method executes local relocation on a model placement where an additional module is added to it for modification with a minimum number of displacements. This method is based on mean-field annealing (MFA), which produces a solution as reliable as a previously used method called simulated annealing. The proposed method requires substantially less time and hardware, and it is less sensitive to the initial and final temperatures. In addition, the solution runtime is mostly independent of the size and complexity of the input model placement. Our proposed MFA algorithm is optimized by enabling module rotation inside an energy function called permissible distances preservation energy. This, in turn, allows more options in moving the engaged modules. Finally, a three-phase cooling process governs the convergence of problem variables called neurons or spins.

$90\%$ 단면감소율로 인발된 전해동의 어닐링시 집합조직과 미세조직 발달에 미치는 전단 변형의 영향 (Effects of Shear Strains on the Developement of Texture and Microstructure of $90\%$ Drawn Copper Wire during Annealing)

  • 박현;이동녕
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2001년도 제4회 압출 및 인발가공 심포지엄
    • /
    • pp.55-62
    • /
    • 2001
  • An electrolytic copper rod was drawn up to $90\%$ in area reduction and annealed under various conditions. The EBSD measurement of the drawn wire showed that in the center region the <111> + <100> fiber duplex texture was dominant, while in the middle and surface regions relatively defused textures developed with a little higher density in <11w>//wire axis. The inhomogeneous texture in the deformed wire gave rise to the inhomogeneous microstructure and texture after annealing. The annealing texture could be classified into the recrystallization texture developed during low temperatures and at the early stage at a high temperature and the growth texture developed after a prolonged annealing at the high temperature. The recrystallization temperature could be explained by the strain energy release maximization model and the growth texture was discussed based on the grain boundary mobility anisotropy.

  • PDF

Annealing Temperature Dependence on the Physicochemical Properties of Copper Oxide Thin Films

  • Park, J.Y.;Kwon, T.H.;Koh, S.W.;Kang, Y.C.
    • Bulletin of the Korean Chemical Society
    • /
    • 제32권4호
    • /
    • pp.1331-1335
    • /
    • 2011
  • We report the results of the characterization of Cu oxide thin films deposited by radio frequency (r.f.) magnetron sputtering at different annealing temperatures. The deposited Cu oxide thin films were investigated by scanning electron microscopy, spectroscopic ellipsometry, X-ray diffraction, atomic force microscopy, Xray photoelectron spectroscopy, and contact angle measurements. The thickness of the films was about 180 nm and the monoclinic CuO phase was detected. The $CuO_2$ and $Cu(OH)_2$ phases were grown as amorphous phase and the ratio of the three phases were independent on the annealing temperature. The surface of Cu oxide films changed from hydrophilic to hydrophobic as the annealing temperature increased. This phenomenon is due to the increase of the surface roughness. The direct optical band gap was also obtained and laid in the range between 2.36 and 3.06 eV.