http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
ECAP법에 의해 제조된 6061 알루미늄 합금의 미세조직과 기계적 특성에 미치는 기공온도의 영향
강효경,김형욱,강석봉 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.2
Equal Channel Angular Pressing(ECAP) was carried out on the 6061 aluminum alloy at room temperature, 373K, 423K, and 473K. The microstructures and mechanical properties of specimens pressed at different temperatures and cycles were investigated. All specimens pressed at different temperatures show ultra fine-grained microstructures with the average grain size less than 0.5 ㎛ and dislocation cell structure. When the pressing temperature increased higher than 423K, the tensile strength of the specimens decreased and the total elongation increased. In case of specimens pressed for 4 cycles at 473K, the fraction of grains having high angle grain boundaries is higher than that pressed at room temperature. The specimen pressed for 4 cycles at room temperature shows higher increase of the 0.2% yield strength, ultimate tensile strength and hardness, and much higher decrease of work hardening index.
카올린으로부터 알루미나 졸의 형성에 미치는 반응인자의 영향
강효경,박홍채,박희찬 ( Hyo Kyoung Kang,Hong Chae Park,Hee Chan Park ) 한국공업화학회 1997 공업화학 Vol.8 No.4
카올린에서 추출된 황산알루미늄 용액을 이용하여 정밀화학 분야에서 많은 이용이 기대되고있는 알루미나 졸의 제조에 대하여 연구하였다. 교반을 하면서 황산알루미늄용액에 암모니아수를 첨가하여 비정질의 일수산화알루미늄(AlO(OH))를 제조하고, 제조된 입자의 표면에 전기이중층을 형성하기 위해서 초산(CH₃COOH)을 투입하여 안정한 알루미나 졸을 제조하였다. 안정한 알루미나 졸의 제조에 미치는 반응온도, 반응시간, 초산의 농도 등의 영향을 조사하였다. 반응온도 50∼90℃, A/C(건조된 알루미나 량/첨가된 초산의 량) 1.6 (몰비)에서 안정한 졸의 합성이 가능하였으며, 반응시간에는 거의 영향을 받지않았다. 또한, 알루미나의 함량이 1-5vol%까지의 범위에서 안정한 졸이 제조되었고, 이때 졸의 입자크기는 약 5-l0nm 정도이었다. The preparation of alumina sol for fine chemical field from kaolin-derived aluminum sulfate solution is performed. Noncrystalline Al0(OH) was prepared by dropping ammonia water into aluminum sufate solution with stirring. Acetetic acid was added to form the electrical double layers on the particle surface of the slurry, which resulted in a stable sol. The influence of the reaction temperature, reaction time, acetetic acid concentration on the preparation of alumina sol were investigated. Dispersed colloid particles of AlO(OH) were prepared at the reaction temperature of 50-90℃ and 1.6 A / C =1.6 (molar ratio), regardless of the reaction time. Stable alumina sol having a particle size of about 5∼10nm was prepared in the range 1∼5vol% alumina content.
AC4C 합금의 기계적 성질에 미치는 주조조건과 열처리의 영향에 관한 연구
강효경,천병욱,최창옥 ( Hyo Gyoung Kang,Byung Wook Cheon,Chang Ock Choi ) 한국주조공학회 1993 한국주조공학회지 Vol.13 No.5
N/A AC4C alloy casts in the metallic mold, zircon sand mold, silica sand mold and shell mold with the pouring temperatures of 680, 710 and 740℃ have been investigated. The tensile strength, elongation and hardness of AC4C alloy castings have been influenced by the kind of molds used. The mechanical properties in zircon sand mold castings were greater than those in other sand mold castings, but were inferior to the properties in metallic mold castings. Eutectic Si particle size and DAS were increased in the order of metallic mold, ziron sand mold, silica sand mold and shell mold. Also, they were increased with the increase of pouring temperatures. DAS, eutectic Si particle size and grain size decreased with the increase of mechanical properties as the cooling rate increased. The eutectic Si particle size and DAS of AC4C alloy castings after T6 treatment were decreased in as-cast. The variation of eutectic Si particle size has been effected on the tensile strength, elongation and fractured surface.