• 한국항행학회논문지
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• 제7권2호
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• pp.211-216
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• 2003

본 논문에서는 오래 전부터 NMOS의 게이트 전극으로 사용된 폴리실리콘을 대체할 수 있는 Ta-Ti 합금의 특성에 대해 연구하였다. 실리콘 기판 위에 열적으로 성장된 $SiO_2$ 위에 Ta과 Ti의 두 타깃을 사용하여 co-sputterring 방법으로 Ta-Ti 합금을 증착하였다. 각각의 타깃은 100W의 sputtering power로 증착하여 시편을 제작하였다. 또한 비교 분석을 위하여 Ta을 100W의 sputtering power로 증착한 시편도 제작하였다. 제작된 Ta-Ti 합금 게이트의 열적/화학적 안정성을 검토하기 위하여 $600^{\circ}C$에서 급속열처리를 수행한 결과 소자의 성능 저하는 나타나지 않았다. 또한 전기적 특성 분석 결과 Ta-Ti 합금은 NMOS에 적합한 일함수인 4.13eV를 산출해 낼 수 있었고, 면저항 역시 폴리실리콘에 비해 낮은 값을 얻을 수 있었다.

• 한국수소및신에너지학회논문집
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• 제18권1호
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• pp.52-59
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• 2007

We investigated the effects of the addition of Mn and $AB_5$ type alloy on the electrochemical characteristics of Ti-Cr-V BCC type alloys as anode materials for Ni-MH battery. The activation behavior and discharge capacity of the BCC type alloys were significantly improved by ball-milling with the $LmNi_{4.1}Al_{0.25}Mn_{0.3}Co_{0.65}$ alloy, because the $AB_5$ type alloy acted as hydrogen path on the surface of the BCC type alloy. Among the Mn substituted alloys($Mn=0.03%{\sim}0.08%$), the $Ti_{0.32}Cr_{0.38}Mn_{0.05}V_{0.25}$ alloy ball-milled with $AB_5$ type alloy exhibited the greatest discharge capacity of $336\;mAh{\cdot}g^{-1}$. In addition, Mn substituted alloys exhibited the lower plateau pressure in P-C- T curve, the better hydrogen storage capacity and faster surface activation compared with the alloy without Mn.

• 소성∙가공
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• 제28권1호
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• pp.27-33
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• 2019

The effect of hardening methods and process parameters on surface hardening of a Ti-6Al-4V Alloy has been investigated in this study. To characterize the effectiveness of the respective surface hardening methods, samples of a Ti-6Al-4V alloy were self-quenched, laser-nitrided, laser-carburized, laser-carbonitrided at the same laser irradiation conditions. This experimental procedure was followed by comparing the microstructural evolutions and mechanical properties of the respective samples after the laser surface hardenings. The hardening characteristics of the respective laser surface hardenings were well defined in this study, and the hardness was significantly influenced by the reaction compounds and laser energy density.

• 한국재료학회지
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• 제10권6호
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• pp.409-414
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• 2000

3%C-10%Cr-5%Mo-5%W, 3%C-10%V-5%Mo-5%W 및 3%C-17%Cr-3%V의 3종류 고합금백주철에 있어서 열처리후의 기지조직의 변태거동을 연구하였다. 15kg 용량의 고주파 유도용해로에 선철, 고철, Fe-Cr, Fe-V, Fe-Mo 및 Fe-W 등을 장입시켜 용해시킨 후 슬래그를 제거시키고 $1550^{\circ}C$에서 Y-block의 펩 주형에 주입시켰다. 적당한 크기로 절단한 시편을 진공분위기하에$950^{\circ}C$에서 5시간동안 우선 균질화처리를 실시하였다. 그 후 다시 이 시편을 $1050^{\circ}C$에서 2시간동안 오스테나이징시킨 후 강제공냉을 행하였다. 강제공냉된 시편을 $300^{\circ}C$에서 3시간 유지시킨 후 템퍼링을 실시하였다. 주방상태에서의 기지조직은 3합금 공히 퍼얼라이트이었으며 강제공냉후에는 마르텐사이트 및 오스테나이트로 변태하였다. 또한 기지조직내에 무수히 많은 이차탄화물 입자들의 석출되었다. 템프링 후 일부 오스테나이트 및 마르텐사이트는 템퍼드마르텐사이트로 변태하였다. 변태하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제37회 하계학술대회 초록집
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• pp.338-338
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• 2009

• 소성∙가공
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• 제27권3호
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• pp.177-183
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• 2018

The influence of electric current on the springback characteristics of AZX311 magnesium alloy and martensitic steel after V-bending test is investigated. Various pulsed electric currents are applied into the specimens followed by a V-bending test, and the changes in the springback angle are measured. In order to evaluate not only the thermal effect but also the athermal effect of electric current on the springback angle, the temperature rises resulting from the applied electric current are measured for all test conditions. As a result, it was found that the springback is significantly decreased as the current density increases. As for the martensitic steel, since the dislocation recovery immoderately occurs at a high electric current density condition of $80A/mm^2$, the optimal current density condition should be required.

• 한국수소및신에너지학회논문집
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• 제17권1호
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• pp.31-38
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• 2006

There are two types of metal hydride electrodes as a negative electrode in a Ni-MH battery, $AB_2$ Zr-based Laves phases and $AB_5$ LM(La-rich mischmetal)-based alloys. The $AB_5$ alloy electrodes have characteristic properties such as a large discharge capacity per volume, easiness in activation, long cycle life and a low cost of alloy. However they have a relatively small discharge capacity per weight. The $AB_2$alloy electrodes have a much higher discharge capacity per weight than $AB_5$ alloy electrodes, however they have some disadvantages of poor activation behavior and cycle life. Therefore, in order to improve the discharge capacity of the $AB_5$ alloy electrode the Zr, Ti and V which are the alloying elements of the $AB_2$ alloys were added to the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}$ alloy which was chosen as a $AB_5$ alloy with a high capacity. The addition of Zr, Ti and V to $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}$ alloy improved the activation to be completed in two cycles. The discharge capacities of Zr 0.02, Ti 0.02 and V 0.1 alloys in $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) were respectively 346, 348 and 366 mAh/g alloy. The alloy electrodes, Zr 0.02, Ti 0.05 and V 0.1 in $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V), have shown good cycle property after 200 cycles. The rate capability of the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) alloy electrodes were very good until 0.6 C rate and the alloys, Zr 0.02, Ti 0.05 and V 0.1, have shown the best result as 92 % at 2.4 C rate. The charge retention property of the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) alloys was not good and the alloys with M content from 0.02 to 0.05 showed better charge retention properties.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.126-129
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• 2005

Microstructures and tensile properties of low carbon steels, 5083 Al alloy and Ti-6Al-4V alloy fabricated by equal channel angular pressing (ECAP) were examined in order to understand their deformation response associated with a formation of an ultrafine grained (UFG) structure. Room temperature tensile properties of UFG low carbon ferrite/pearlite steels and UFG ferrite/martensite dual phase steel were compared for exploring a feasibility enhancing the strain hardening capability of UFG materials. In addition, low temperature and high strain rate superplasticity of the two grades of the UFG 5083 Al alloy, and Ti-6Al-4V alloy were presented. From the analysis of a series of experiments, it was found that UFG materials exhibited the enhanced mechanical properties compared to coarse grained counterparts.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1023-1024
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• 2006

Al-8Fe-2Mo-2V-1Zr alloys were prepared by the gas atomization/hot extrusion and the melt spinning/hot extrusion. For the gas atomized and extruded alloy, equiaxed grains with the average size of 400 nm and finely distributed dispersoids with their particle sizes ranging from 50nm to 200nm were observed. For the melt spun and hot extrusion processed alloy, refined microstructural feature consisting of equiaxed grains with the average size of 200nm and fine dispersoids with their particle sizes under 50nm appeared to exhibit a difference in microstructure. Strength of the latter alloy was higher than that for the former alloy up to elevated temperatures.

• 소성∙가공
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• 제15권2호
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• pp.105-111
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• 2006

A study was made to investigate the microstructure and the mechanical properties of low-carbon steel, Al-Mg alloy and Ti-6Al-4V alloy each representing bcc, fcc and hcp crystal structures, respectively fabricated by equal-channel angular(ECA) pressing. After a series of ECA pressings was performed, most grains were significantly refined below ${\mu}m$ in diameter with high mis-orientation of grain boundaries irrespective of different crystal structure used. Regarding the strain hardening capability, tensile tests of ultrafine grain (UFG) dual-phase (ferrite/martensite) steel which was different from UFG ferrite-pearlite steel were carried out at ambient temperature, and corresponding mechanical properties were discussed in relation to modified C-J analysis. Low-temperature and/or high strain-rate superplasticity of the UFG Al-Mg alloy and UFG Ti-6Al-4V alloy were also studied. Based on the analysis used in this study, it was concluded that UFG alloys exhibited the enhanced mechanical properties as compared to coarse-grained (CG) counterparts.