http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
초초임계압 발전용 소재의 장시간 열처리에 따른 미세조직 변화와 기계적 특성의 상관관계 연구
주성욱,유정훈,신기삼,허성강,이재현,석진익,김정태,김병훈,Joo Sungwook,Yoo Junghoon,Shin Keesam,Hur Sung Kang,Lee Je-Hyun,Suk Jin Ik,Kim Jeong Tae,Kim Byung Hoon 한국재료학회 2005 한국재료학회지 Vol.15 No.1
For the good combination of high-temperature strength, toughness and creep property, $9-12\%$ chromium steels are often used for gas turbine compressors, steam turbine rotors, blade and casing. In this study, the correlation of microstructural evolution and mechanical properties was investigated fur the specimens heat-treated at 600, 650 and $700^{\circ}C$ for 1000, 3000 and 5000 hrs. The microstructure of as-received specimen was tempered martensite with a high dislocation density, small sub-grains and fine secondary phase such as $M_23C_6$. Aging for long-time at high temperature caused the growth of martensite lath and the decrease of dislocation density resulting in the decrease in strength. However, the evolution of secondary phases had influence on hardness, yield strength and impact property. In the group A specimen aged at $600^{\circ}C\;and\;650^{\circ}C$, Laves phase was observed. The Laves phase caused the increase of the hardness and the decrease of the impact property. In addition, the abrupt growth of secondary phases caused decrease of the impact property in both A and B group specimens.
흑연 함량에 따른 알루미늄 기지 복합재료의 방전플라즈마소결 거동 및 방열 특성
권한상,박재홍,주성욱,홍상휘,문지훈,Kwon, Hansang,Park, Jehong,Joo, Sungwook,Hong, Sanghwui,Mun, Jihoon 한국분말야금학회 2016 한국분말재료학회지 (KPMI) Vol.23 No.3
Composite materials consisting of pure aluminum matrix reinforced with different amounts of graphite particles are successfully fabricated by mechanical ball milling and spark plasma sintering (SPS) processes. The shrinkage rates of the composite powders vary with the amount of graphite particles and the lowest shrinkage value is observed for the composite with the highest amount of graphite particles. The current slopes of time increase with increase in the amount of graphite particles whereas the current slopes of temperature show the opposite trend. The highest thermal conductivity is achieved for the composite with the least amount of graphite particles. Therefore, the thermal properties of the composite materials can be controlled by controlling the amount of the graphite particles during the SPS process.
이준숭 ( Jun Soong Lee ),문지훈 ( Ji Hun Mun ),주성욱 ( Sungwook Joo ),이승욱 ( Seung Uk Lee ),김민일 ( Min Il Kim ) 한국공업화학회 2023 공업화학 Vol.34 No.6
탄소블록의 열전도도를 증가시키기 위하여 탄소블록 제조 공정 중 nano-diamond (ND)를 첨가하였다. 첨가된 ND는 탄화 과정에서 바인더 피치의 휘발로 인하여 생성된 탄소블록의 기공을 제어하였다. ND의 첨가는 코크스 및 바인더 피치의 혼련 공정에 추가하였으며, 성형, 탄화를 거쳐 탄소블록을 제조하였다. 첨가된 ND의 양이 증가할수록 탄소블록의 ND 비율이 증가하였다. 첨가된 ND는 탄화 과정에서 바인더 피치의 휘발로 인하여 발생하는 가스의 이동 통로역할을 하여 탄소블록의 밀도를 높이고, 기공률을 감소시켰다. ND의 첨가를 통하여 높아진 밀도, 낮아진 기공률, ND의 높은 열전도도를 통하여 탄소블록의 열전도도를 향상시킬 수 있었다. Nano-diamond (ND) was added during the carbon block preparation process to increase the thermal conductivity of the carbon block. Added ND controlled the generated pore of carbon block due to the volatilization of the binder pitch during the carbonization process. The ND was added to the kneading process of coke and binder pitch, and carbon blocks were prepared by pressing and carbonization. As the amount of added ND increased, the ND ratio of the carbon block increased. The added ND made a pass-way for generated gas by volatilizing the binder pitch during the carbonization process, increasing the density of the carbon block and reducing the porosity. The thermal conductivity of the carbon block was improved by increased density, lowered porosity, and the high thermal conductivity of added ND.
자동차 시동용 LFP 배터리 팩의 혹한기 시동성 향상을 위한 열선 시스템 적용에 따른 열 유동 해석
우영한(Younghan Woo),강석원(Seokwon Kang),이준숭(Junsoong Lee),박문식(Moonsic Park),김성진(Sungjin Kim),성동길(Donggil Sung),주성욱(Sungwook Joo) 한국생산제조학회 2021 한국생산제조학회지 Vol.30 No.1
A numerical simulation for evaluating thermal performance was performed to determine the possibility of replacing existing lead-acid 12 V batteries with lithium-ion batteries. In batteries used for starting vehicles, low-temperature (≤–20℃) starting performance and lifespan decrease significantly. Therefore, a lithium iron phosphate (LFP) battery system with a relatively high energy density at low temperatures was studied. A system for self-energy heating was designed to improve operability under cold-weather conditions. In particular, the battery pack case, battery cell array, and heating system of the proposed system were designed to be compatible. Furthermore, a thermal performance simulation was performed using computational fluid dynamics and heat transfer techniques based on the estimated thermal properties of each component. The results showed that the self-heating LFP battery pack system reached its startable temperature (–3℃) after 75 s when 249 W of power was applied in a low-temperature (–20℃) environment.
가스터빈용 소재 IN 738LC 합금의 미세조직 열화거동
유정훈,주성욱,신기삼,김의현,정진성,장성호,송기욱,하정수 국립7개대학공동논문집간행위원회 2002 공업기술연구 Vol.2 No.-
IN 738LC, used as gas-turbine for power generation, was heat treated at 750℃, 850℃, 950℃ for 1000, 2000, and 4000 hrs. and the microstructural evolution are examined using optical microscope, XRD, SEM/EDS. For comparison, part of gas turbine used for 18439 hours for power generation was also examined. The results showed γ´, the main strengthening elements in this alloy, was about 300 nm and was about 56% in as-cast samples. The volume fraction of γ´peaked at 2000 hours at 750℃ and then decreased at further or longer heat treatment. The average diameter of the γ´ which was about 200 nm increased to about 1㎛. Carbides were formed at dendrite, cell, or grain boundaries which was ascribed to the segregation caused by solute redistribution during solidification. It was found that the at low temperature, M_6C type carbides formed, whereas carbides of M_23C_6 type formed at higher temperature, or at longer degradation.