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김동원(Dong-Won Kim),조규일(Kyu-Il Cho),김현근(Hyun-Keun Kim),강자연(Ja-Youn Kang),이원혁(Won-Hyuk Rhee),황금철(Keum-Cheol Hwang) 한국표면공학회 2008 한국표면공학회지 Vol.41 No.5
The porous metal material is used for injection metal mold with a great deal of gas production because it makes plenty of gas exhausted through pores formed in the metal mold. A canning HIP method was conventionally used for manufacturing of porous metals, but because of difficulty of process control and high cost of production its application was limited. In this experiment, porous metal mold material was produced by an enhanced vacuum sintering method with simply controlled and economical process and porosities/mechanical properties with variation of sintering temperature and duration time during vacuum sintering were studied. As a result, quality goods were obtained at optimized conditions as follows: sintering temperature of 1230℃, duration time of 2 hr and showed superior properties in wear loss and thermal conductivity and the same properties in hardness, TRS (Transverse Rupture Strength), and thermal expansion coefficient in comparison with those under canning HIP.
TiC 분산된 니켈기 합금의 미세조직 및 기계적 특성에 미치는 열처리 영향
홍성현,황금철,이원혁,진억용,Hong, Seong-Hyeon,Hwang, Keum-Chul,Rhee, Won-Hyuk,Chin, Eog-Yong 한국분말야금학회 2002 한국분말재료학회지 (KPMI) Vol.9 No.6
The microstructures and properties of TiC dispersed nickel-base alloy were studied in this work. The alloy prepared by powder metallurgical processing was solution treated, 1st-aged at $880^{\circ}C$ for 16 hours, and then 2nd-aged at $760^{\circ}C$ for 4 hours. Microstucture of sintered specimen showed that TiC particles are uniformly dispersed in Ni base alloy. In the specimen aged at $880^{\circ}C$ for 8 hours, the fine $\gammaNi_3$(Al,Ti) precipitates with round shape are observed and the very fine $\gammaNi_3$(Al,Ti) particles with round shape are precipitated in the specimen aged at $760^{\circ}C$ for 4 hours. The presence of ${\gamma}$precipitates in TiC/Ni base alloy increased the hardness and wear resistance of the specimen. The hardness and wear resistance of the Ni-base with TiC are higher than those of conventional Ni-base superalloy X-750 because of dispersion strengthening of TiC particles. The hardness, transverse rupture strength and resistance of the specimen 2nd-aged at $760^{\circ}C$ for 4 hours are higher than those of 1st-aged specimen due to ultrafine $\gammaNi_3$(Al,Ti) precipitates.
B<sub>4</sub>C 함량에 따른 6061 Al-B<sub>4</sub>C 복합분말의 소결 특성 연구
박진주,홍성모,김경열,이민구,이창규,이원혁,이양규,Park, Jin-Ju,Hong, Sung-Mo,Kim, Kyoung-Yeol,Lee, Min-Ku,Rhee, Chang-Kyu,Rhee, Won-Hyuk,Lee, Yang Kyu 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.3
In the present work, 6061 Al-$B_4C$ sintered composites containing different $B_4C$ contents were fabricated and their characteristic were investigated as a function of sintering temperature. For this, composite powders and their compacts with $B_4C$ various contents from 0 to 40 wt.% were fabricated using a planetary ball milling equipment and cold isostatic pressing, respectively, and then they were sintered in the temperature ranges of 580 to $660^{\circ}C$. Above sintering temperature of $640^{\circ}C$, real density was decreased due to the occurrence of sweat phenomena. In addition, it was realized that sinterability of 6061Al-$B_4C$ composite material was lowered with increasing $B_4C$ content, resulting in the decrease in its real density and at the same time in the increment of porosity.
피스톤 경량화를 위한 금속복합소재 개발과 기초 특성 평가
백승주(Seungju Beak),이정구(Jungkoo Lee),김지윤(Jiyun Kim),이원혁(Won Rhee),임규철(Gyu Chul Im),이기형(Kihyung Lee) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6
점차 강화되는 자동차 배기규제를 대응하기 위해 엔진의 연비향상 및 배출물 저감 기술이 매우 중요한 시점이다. 다양한 배기 저감 기술 중 소재 및 부품의 경량화는 엔진의 효율을 향상시켜 자동차의 연비 및 배기 성능향상을 기대할 수 있다. 일반적으로 자동차의 중량 10%경량화는 약 3.8%연비 향상 효과를 보이는 것으로 알려져 있다. 이러한 자동차 경량화 연구는 다방면에서 수행되고 있으며, 기존 자동차 부품 경량화의 방안으로 신소재 개발을 통해 동등한 수준의 기계적 강도를 갖는 대체 부품 개발에 대한 연구가 활발하게 진행되고 있다. 엔진의 피스톤은 폭발행정에서 발생되는 고온·고압의 힘을 받아 고속으로 실린더 내부를 왕복운동 하기 때문에 높은 강도와 더불어 경량화가 반드시 필요한 부품이라고 할 수 있다. 기존의 피스톤은 알루미늄(AI) 합금을 사용하여 경량화를 도모하지만, 내마모성이 낮은 문제점 때문에 철강 소재를 사용하여 인서트링의 내마모성을 높이고 있다. 이에 따라, 철강 소재와 알루미늄 합금의 이종소재 접합의 한계로 인하여 계면에서의 기공 혹은 접합 불량 등의 문제가 지속적으로 발생하고 있다. 본 연구에서는 기존 철강 소재의 인서트 링이 적용된 피스톤의 기초 특성을 평가하고, 이와 동등한 수준의 대체품 개발을 위해 AI복합재료의 소재를 선정하고 그에 대한 특성 평가를 수행하였다. 또한, 기계적 특성을 평가하기 위해 인장강도와 내마모성 및 경도 측정을 진행하였다.
이태성,이원혁,조시현,김재오,성기원,리화룡 대한신경외과학회 1986 Journal of Korean neurosurgical society Vol.15 No.4
Recently, the authors experienced the thirty - one cases of cervical fracture and dislocation. Among them, nineteen cases underwent surgical treatment and remained conservative treatment. There are three ways in operation; 1) anterior approach(Cloward, Smith-Robinson method). 2) posterior approach. 3) combined approach(modified Smith-Robinson and posterior fusion). We did a combined approach and the results were excellent.
이태섭,양대동,성기원,김재오,이원혁,리화룡 대한신경외과학회 1986 Journal of Korean neurosurgical society Vol.15 No.4
The authors managed forty cases of chronic subdural hematoma which were diagnosed by carotid angiography and computerized tomographic scanning. Within fortieth-day after onset, only two cases are absorbed without any specific treatment and clearly.