Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of 700 μm was formed by a heat treatment at 665˚C for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.

This study was conducted to investigate the effect of parity and region on the live body charateristics of Hanwoo cows. The data used were logissimus muscle area (LMAU), back fat thickness (BFTU), marbling score (MSU), and p8 point fat thickness (P8 FTU), by ultrasound from 1,239 heads of hi-lok branded Hanwoo cows. Based upon ultrasound characteristics of LMAU, BFTU, MSU and P8 FTU were significantly high in Hanwoo cows in Hwacheon area. Live body characteristics were increased with the parity, however estimated value tended to decreased after sixth parturition. Also, comparative of pre or after parturiti- on on the live body characteristics, pre parturition value showed little lower than after parturition

This study was to invesigate the effect of dietary supplemention of Pozzolan, Chromium-methionine chelate and rhus verniciflua stokes additive feed on growth performance and ultrasound live body characteristics in finishing Hanwoo steer. The animal used in the experiment were a total of 17 heads and weighted 577.09±35.90㎏. The experimental diets were basal hi-lok branded only concentrat and rice straw and 4% Rhus, 0.4% Cramin and 2% Pozzolan, which additice in basal diet. Individually average daily gain was tended to decreased with treated group. Ultrasound back fat thickness and marbling score were not significantly different(p<0.05)between teratment, however Pozzolan additive treat was showed tend to increased. Longissimus muscle area was showed tended to decreased in the Pozzolan treatment.

This study was carried out to determine the maintenance and social behavior characteristics of Hanwoo steers by season. Forty eight Hanwoo steers were video-recorded at 15, 17 and 19 months of age for behavior measurement. Hanwoo steers spent more feeding time (p<0.05) in autumn than in summer and/or winter. Standing time was linearly increased (p<0.05) along with seasonal transition, from summer to winter. The rice straw intake speed was the fastest the summer, whereas the concentrate intake speed was relatively fast in winter. Furthermore, Hanwoo steers showed more behavior time and count for lying down (p<0.05) and drinking (p<0.05) in summer than in autumn and winter. Also, Hanwoo steers spent less count (p<0.05) self grooming and scratching in summer.

Ti 과 AI의 고순도 원소 박판을 이용하여 열간프레스장치에서 고온자전합성법으로 TiAI계 금속간화합물을 제조하였다. 원소 박판에서 TiAl3 금속간화합물을 제조하는 데 승온속도, 압력, 온도 등의 변수가 고온자전합성에 영향을 미치는 중요한 인자다. 특히 승온속도는 반응합성온도를 결정하는 인자로서 본 실험에서 DTA 분석을 이용하여 공정변수를 결정하였다. DTA 분석결과에 따르면, Ti와 AI의 계면에서 반응합성은 AI의 용융점 이하와 이상의 온도에서 두 번 발생함을 알 수 있다. 또한 승온속도가 증가할수록 두 반응합성온도는 증가하였다. 10층의 Ti 박판과 9층의 AI 박판을 20˚C/min의 승온속도로 고온자전합성시킨 후, 810˚C와 240MPa의 압력에서 4시간 동안 열처리한 결과 700μm 두께의 TiAI계 금속간화합물 판재를 제조하였으며, XRD 회절과 SEM으로 확인하였다.

Melt-overflow 급냉응고장치를 이용하여 두께 약 300μm, 폭 10mm의 Mg-Zn합급 스트립을 연속적으로 제조하였다. 또한 알루미늄을 첨가하여, 첨가원소에 따른 결정립미세화와 기계적강도에 미치는 영향을 조사하였다. 스트립의 미세응고조직은 전자현미경(TEM, SEM)과 image analyzer를 이용하여 분석하였으며, 경도시험으로 기계적특성을 평가하였다. Mg-5wt%Zn합금 스트립의 경도는 결정립크기의 제곱근에 반비례하여 급냉응고에 의한 결정립미세화 효과로 같은 조성의 일반주조 합금보다 2배 이상의 높은 경도값을 가지며, 알루미늄을 첨가함으로서 2배 정도의 결정립미세화 효과를 얻어 경도가 더욱 증가하였다. 결정입계를 따라 생성된 금속간화합물은 마그네슘화합금의 입계부식을 방지하여 우수한 내식성을 갖는다. 따라서 적절한 합금설계와 급냉응고법을 적용시키면 마그네슘합금의 취약성을 보완하며 경량성의 장점을 최대한 활용할 수 있다.