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신광선,정화철,나영기(Kwang Seon Shin),Hwa Chul Jung,Young Gee Na 한국자동차공학회 2003 한국자동차공학회 Symposium Vol.2003 No.5
As the global concern increases rapidly on environmental protection associated CO₂emissions, the major car manufacturers in U.S.A., Europe and Japan have continuously strived to improve the automotive fuel efficiency for the past two decades. Vehicle weight reduction is one of the major methods for improvement of the automotive fuel efficiency. In recent years, there has been an increasing trend to use light metals and alloys for automotive components. Magnesium alloys have the lowest density (1.8g/cm³)among the commercially available structural metals and the excellent specific strength and stiffness. Magnesium alloys also have exceptional dimensional stability, excellent machinability, high damping capacity, high electrical and thermal conductivities, and good fatigue resistance. In the past decade, the demand and usage of the magnesium alloys have increased drastically for structural applications, particularly in the automotive industry. Most of the magnesium automotive industry. Most of the magnesium automotive components are manufactured by die casting process and, therefore, active researches are being carried out on melt protection, die design, and corrosion and mechanical property characterization. Furthermore, new alloys are being developed for improved corrosion resistance and mechanical properties and new processes including semi-solid processing are also under development for better production efficiency and product quality. In the present paper, the application status and manufacturing technologies of magnesium alloys for the automotive component are reviewed.
기계적 밀링 공정을 이용한 준결정 강화 알루미늄 복합재료의 제조
장우길,신광선,Jang Woo Kil,Shin Kwang Seon 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.3
Aluminum matrix composites strengthened by the quasi-crystalline (QC) phase were developed in the present study. The icosahedral $Al_{65}Cu_{20}Fe_{15}$ phase was produced by gravity casting and subsequent heat treatment. The mechanical milling process was utilized in order to produce the Al/QC composite powders. The microstructures of the composite powders were examined by optical microscopy (OM) and scanning electron microscopy (SEM). The composite powders were subsequently canned, degassed and extruded in order to produce the bulk composite extrusions with various volume fractions of QC. The microstructure and mechanical properties of the extrusions were examined by OM, SEM, Vickers hardness tests and compression tests. It was found that the microstructures of the Al/QC composites were uniform and the mechanical properties could be significantly improved by the addition of the QC phase.
중력주조 AM60 마그네슘 합금의 강화 거동에 미치는 Si 및 Ca 첨가영향
김재우,김도향,신광선 ( Jae Woo Kim,Do Hyang Kim,Kwang Seon Shin ) 한국주조공학회 1998 한국주조공학회지 Vol.18 No.4
N/A Effects of Si and Ca additions on the mechanical properties of AM60 based Mg alloys have been investigated. Hardness of the AM60 based Mg alloys reached a maximum value after aging for approximately 33 hours but the amount of hardness increase was negligible. The poor age hardening response of the alloys was due to low Al content, which implies that Al content must be >6 wt.% to observe age hardening effect. The tensile and yield strength increased with increasing AI, Si, and Ca content but elongation decreased with increasing Al and Si content. The best mechanical properties obtained in AM 40-2.5Si-0.2Ca alloy after T4 heat treatment were as follows; tensile strength 193.4 MPa, yield strength 79.2 MPa, and elongation 11.2%. High temperature property obtained from creep test was also improved by introducing Mg₂Si which has high hardness, high melting temperature and low thermal expansion coefficient. (Received February 6, 1998)