http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
결정립 조대화된 기계적 합금화 ODS NiAl의 Creep 성질
어순철,서성재,Eo, Sun-Cheol,Seo, Seong-Jae 한국재료학회 1997 한국재료학회지 Vol.7 No.11
NiAI기 산화물 분산강화(Oxide Dispersion Strengthende:ODS)합금을 기계적 합금화 (Mechanical Alloying: MA)방법으로 제조하였으며, 열간압축방법으로 성형하였다. 연이어 단순항온처리에 의한 정상결정립성장과 특성조건에서의 thermomechanical treatment 에 의한 이차재결정화를 유도하였다. 결정립 조대화된 ODSD MA NiAI의 creep 성질 및 이에 조대화된 미세조직은 creep 성질이 저하된 반면, 이차재결정화된 MA NiAI의 creep성질은 크게 향상되었다. 이 creep 성질의 향상은 이차재결정화의 특성인 급격한 결정립의 조대화, 분산상의 성장억제 및 grain aspect ratio의 증가에 기인한 것으로 사료되었다. 이차재결정화된 ODS MA NiAI의 creep또는 glide controlled dislocation creep임을 제시하지만, 전체 creep속도가 결정립 크기 및 grain aspect ratio의 영향을 크게 받은 것을 볼 때, 결정립계 미끄럼기구가 주 creep 기구와 조합되어 MA NiAI의 전체 creep기구에 영향을 준 것으로 추정할 수 있었다.
기계적 합금화 Iron Silicide의 열간성형 및 열처리에 의한 상변화
어순철,김일호,황승준,조경원,최재화,Eo, Sun-Cheol,Kim, Il-Ho,Hwang, Seung-Jun,Jo, Gyeong-Won,Choe, Jae-Hwa 한국재료학회 2001 한국재료학회지 Vol.11 No.12
An n-type iron$silicide(Fe_{0.98}Co_{0.02}Si_2)$has been produced by mechanical alloying process and consolidated by vacuum hot pressing. Although as-milled powders after 120 hours of milling did not show an alloying progress,${\beta}-FeSi_2$phase transformation was induced by isothermal annealing at$830{\circ}C$for 1 hour, and the fully transformed${\beta}-FeSi_2$phase was obtained after 4 hours of annealing. Near fully dense specimen was obtained after vacuum hot pressing at$ 1100{\circ}C$with a stress of 60MPa. However, as-consolidated iron silicides were consisted of untransformed mixture of ${\Alpha}-Fe_2Si_5$and ${\varepsilon-FeSi$phases. Thus, isothermal annealing has been carried out to induce the transformation to a thermoelectric semiconducting${\beta}-FeSi_2$phase. The condition for${\beta}-FeSi_2$transformation was investigated by utilizing DTA, SEM, and XRD analysis. The phase transformation was shown to be taken place by a vacuum isothermal annealing at$830{\circ}C$and the transformation behaviour was investigated as a function of annealing time. The mechanical properties of${\beta}-FeSi_2$materials before and after isothermal annealing were characterized in this study.
Half-Heusler TiCoSb1-xSnx 합금계의 기계적 합금화에 의한 합성
어순철 忠州大學校 2012 한국교통대학교 논문집 Vol.47 No.-
Half-heusler TiCoSb1-xSnx (0.00≤x≤0.05) alloys were prepared by mechanical alloying of elemental powders, and consolidated by vacuum hot pressing. Phase transformations during mechanical alloying and hot consolidation were investigated using XRD and SEM. Single phase of Half-heusler phases were successfully produced in all doping ranges in as-milled state, but a little fraction of CoSb phase appeared after hot pressing. The process can be an alternative processing route for the synthesis of thermoelectric Half-heusler compounds.
열간 압축 공정에 의한 Zn<sub>4</sub>Sb<sub>3</sub>의 직접 고상 반응 합성 및 열전특성
어순철,Ur Soon-Chul 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.4
Direct solid state synthesis by hot pressing has been applied in order to produce high efficiency $Zn_4Sb_3$ bulk specimens. Single phase $Zn_4Sb_3$ with 98.5% of theoretical density was successfully produced by direct hot pressing of elemental powders containing 1.2 at.% excess Zn. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of other studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by direct synthesis were measured and are comparable to the published data. Direct solid state synthesis by hot pressing provides a promising processing route in this material.
고상 합성과 진공 압축성형에 의한 Zn<sub>4</sub>Sb<sub>3</sub>의 제조 및 열전특성
어순철,Ur Soon-Chul 한국재료학회 2005 한국재료학회지 Vol.15 No.7
Thermoelectric $Zn_4Sb_3$ alloys were synthesized by a conventional powder metallurgy process consisting of solid state reaction and hot pressing. Single phase $Zn_4Sb_3$ was successfully produced by the annealing of cold compact starting with the mixed elemental powders, and subsequent hot pressing yielded single phase bulk specimens without microcracks. Phase transformations in this alloy system during synthesis were investigated using XRD, SEM and EDS. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of analogue studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by this process are comparable to the published data. Synthesis by solid state reaction and hot pressing offers a potential processing route to produce a bulk $Zn_4Sb_3$.?
어순철 忠州大學校 2003 한국교통대학교 논문집 Vol.38 No.4
Thermoelectric Zn4Sb3 bulk specimens were produced by mechanical alloying using elemental powders and consolidated by hot pressing. Single phase Zn4Sb3 was not obtained using a nominal stoichiometric composition, but near single phase Zn4Sb3 with remnant elemental Zn having a relatively high density was produced using a nominally 11.7 at.% Zn rich powders. Phase transformations during mechanical alloying were systematically investigated using XRD and SEM.
Electronic Transport Properties of Ni-doped CoSb3 Prepared by Hot Pressing
어순철,김일호 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.3
Ni-doped CoSb3 skutterudites (Co1−xNixSb3) were prepared by hot pressing, and their electronic transport properties were examined. Single-phase δ-(Co,Ni)Sb3 was successfully obtained, but it decomposed to δ-(Co,Ni)Sb2 and Sb when x ≥ 0.2, which means that the solubility limit of Ni in Co is x < 0.2. The negative signs of the Seebeck coefficients for all Ni-doped specimens revealed that Ni atoms acted as n-type dopants by substituting for Co atoms. The electrical resistivity and the thermal conductivity decreased with increasing Ni doping level. The ZT (dimensionless figure of merit) value was considerably enhanced by the Ni doping, and the optimum composition was found as Co0.9Ni0.1Sb3 for Ni-doped CoSb3 prepared by hot pressing.
Thermoelectric Properties of Tin-Filled Skutterudites Prepared by Mechanical Alloying Process
어순철,권준철,김일호 대한금속·재료학회 2008 METALS AND MATERIALS International Vol.14 No.5
Sn-filled (Fe,Co)Sb₃ skutterudites of the form of SnyFe3Co5Sb24 (0 ≤ y ≤ 1.5) were synthesized by the mechanical alloying of elemental powders followed by vacuum hot pressing. The phase transformations that occur during both mechanical alloying and vacuum hot pressing were examined by X-ray diffraction. Single-phase Sn-filled skutterudite was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. The thermoelectric properties of the hot-pressed specimens were evaluated as a function of temperature and tin content. The void filling of tin (up to y = 1.0) in Fe₃Co5Sb24 appeared to increase the thermoelectric figure of merit.
기계적 합금화에 의한 Zn<sub>4</sub>Sb<sub>3</sub> 열전소재의 합성 및 열전 특성
어순철,Ur Soon-Chul 한국재료학회 2004 한국재료학회지 Vol.14 No.8
Thermoelectric $Zn_{4}Sb_3$ alloy powders were synthesized from elemental powders by mechanical alloying process and consolidated by hot pressing under controlled atmosphere. Single phase $Zn_{4}Sb_3$ was not obtained using a nominal stoichiometric composition, but near single phase $Zn_{4}Sb_3$ with remnant elemental Zn having a relatively high density was produced using a nominally 11.7 $at.\%$ Zn rich powders. Phase transformations during mechanical alloying were systematically investigated using XRD and SEM. Thermoelectric and transport properties were evaluated for the hot pressed specimens and compared with results of analogous studies.
어순철 忠州大學校 2004 한국교통대학교 논문집 Vol.39 No.1
Solid state synthesis by hot pressing has been used in order to produce high efficiency Zn4Sb3 bulk specimens. Single phase Zn4Sb3 with 98.5% of theoretical density were successfully produced by direct hot pressing of elemental powders containing 1.2 at.% excess Zn. Direct synthesis by hot pressing provides an optional processing route in this material.