http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
반응고 Al-Zn-Mg계 합금의 반용융 압출을 위한 재가열 시 결정립 성장 억제에 미치는 Ca 첨가의 영향
박형원 ( Hyung Won Park ),김대환 ( Dae Hwan Kim ),심성용 ( Sung Yong Shim ),김희경 ( Hee Kyung Kim ),성봉학 ( Bong Hak Seong ),최창옥 ( Chang Ock Choi ),임수근 ( Su Gun Lim ) 한국주조공학회 2011 한국주조공학회지 Vol.31 No.6
There is thixo-extrusion to form high strength aluminum alloy. But, it is a problem that grains become grain coarsening during reheating process because the alloy was exposed at high temperature. In order to solve grain growth during reheating process, calcium was added in Al-Zn-Mg alloys. Primary a grain sizes of semi-solid Al-Zn-Mg-(0, 0.4, 0.6 and 0.9, wt.%)Ca were measured with image analyzer after reheating. Measured primary a grain sizes were applied to LSW(Lifshitz-Slyozov and Wagner) equation to check the effect of Ca on grain coarsening. Coarsening rate constant K values of semi-solid Al-Zn-Mg-(0, 0.4, 0.6 and 0.9, wt.%)Ca alloys were 371 mm3s-1, 247 mm3s-1, 198 mm3s-1 and 166 mm3s-1, respectively. As increasing calcium content, K value decreased which means grains are refined. Also, grains of calcium addition were more spherical than that of calcium free.
김대환 ( Dae Hwan Kim ),정현주 ( Hyun Ju Jung ),심성용 ( Sung Yong Shim ),임수근 ( Su Gun Lim ),이상용 ( Sang Yong Lee ) 한국주조공학회 2014 한국주조공학회지 Vol.34 No.4
This work presents the results of a thixo-extrusion process applied to aluminum alloy and and reheating characteristics of semisolid A356 Alloy using have been discussed. The reheating experiment was performed using an electric resistance furnace and multistage heating for uniform reheating. The thixo-extrusion was performed at the optimal reheating conditions of the semi-solid A356 alloy, the the extrusion conditions were an extrusion ratio of 33 and ram speed of 6 mm/sec. The results showed that the thixoextrusion of semi-solid A356 alloy fabricated by the cooling slope reduced the extrusion pressure by 180% in comparison with hot extrusion, and that a sound extrusion could be obtained in spite of the same extrusion ratio and strain rate.
Mg 첨가에 따른 A356 합금의 열처리 및 기계적 특성 변화
조재찬 ( Jae-chan Jo ),김광삼 ( Kwang-sam Kim ),임인택 ( In-taek Im ),김대환 ( Dae-hwan Kim ),심성용 ( Sung-yong Shim ),임수근 ( Su-gun Lim ) 한국주조공학회 2016 한국주조공학회지 Vol.36 No.6
The effects of Mg addition on heat treatment and mechanical properties of A356 alloy were investigated. With increased amounts of Mg addition to A356 alloy, the grain size decreased and eutectic Si was refined. And, this process can improve the mechanical properties. Solid solution heat treatment causes the spheroidizing of eutectic Si. In this study, although eutectic Si was refined with Mg addition, solid solution time increased from 2 hours to 6 hours with Mg addition, and aging time also increased, from 4 hours to 8 hours. After heat treatment, Mg2Si remained in a formation of Chinese script. And, Chinese script Mg2Si formed with Mg addition caused a reduction of the elongation of the alloys according to the stress concentration.
Al-8.7Zn-2.8Mg-2.6Cu+0.1wt.%Sc Al 합금 압출재의 시효 거동 및 기계적 성질
김광삼,심성용,임수근,이상용 慶尙大學校 經營行政大學院 2004 工學硏究院論文集 Vol.20 No.-
7000계 알루미늄 합금은 시효경화에 의해 기계적 성질이 크게 향상됨으로 항공기 등 수송기기의 구조재료로서 이용되고 있으며, 합금이 개발된 이후 지속적인 성능향상을 위한 연구가 진행중이다. Al 합금에 있어 Sc 첨가는 Al_(3)Sc 상의 생성에 의한 결정립 미세화 및 분산 강화에 의해 효과적으로 강도를 향상 시킬 수 있다. 따라서 본 연구에서는 Al-8.7Zn-2.8Mg-2.6Cu+0.1wt.%Sc 합금 압출제를 이용하여 시효 열처리를 실시하여 시효 거동과 기계적 성질을 조사하였으며, 열처리에 따른 기계적 성질을 조사하였다. 압출재의 미세 조직 관찰 결과 Al_(3)Sc상이 기지 전반에 압출 방향으로 분포되어 있음을 알 수 있었고, 시효 거동 관찰 결과 최대경도 지점이 2400분에서 나타났으며, 시효 경화성 또한 기존의 Al7075 합금 보다 우수하였으며, 강도 증가에 있어서도 T6 처리한 경우 인장강도 657MPa로 나타났으며, 연신율의 경우 5%이었다.