In order to broaden the range of application of light weight aluminum alloys, it is necessary to enhance the mechanical properties of the alloys and combine them with other materials, such as cast iron. In this study, the effects of adding small amounts of Cu and Zr to the Al-Si-Mg based alloy on tensile properties and corrosion characteristics were investigated, and the effect of the addition on the interfacial compounds layer with the cast iron was also analyzed. Although the tensile strength of the Al-Si-Mg alloy was not significantly affected by the additions of Cu and Zr, the corrosion resistance in 3.5 %NaCl solution was found to be somewhat lowered in this research. The influence of Cu and Zr addition on the type and thickness of the interfacial compounds layer formed during compound casting with cast iron was not significant, and the main interfacial compounds were identified to be Al5FeSi and Al8Fe2Si phases, as in the case of the Al-Si-Mg alloys.
In the present work, Inconel 718 alloy is additively manufactured on the Ti-6Al-4V alloy, and a functionally graded material is built between Inconel 718 and Ti-6Al-4V alloys. The vanadium interlayer is applied to prevent the formation of detrimental intermetallic compounds between Ti-6Al-4V and Inconel 718 by direct joining. The additive manufacturing of Inconel 718 alloy is performed by changing the laser power and scan speed. The microstructures of the joint interface are characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and micro X-ray diffraction. Additive manufacturing is successfully performed by changing the energy input. The micro Vickers hardness of the additive manufactured Inconel 718 dramatically increased owing to the presence of the Cr-oxide phase, which is formed by the difference in energy input.
인삼의 안정적인 생산 및 합리적인 병해방제에 기여하기 위하여 연구를 실시한 결과 갈잎 퇴비에서 분리된 Streptomyces lauretii B8180과 Bacillus subtilis B8856, Burkholderia cepacia B7944 세 균주의 인삼병원균 5종에 대한 항균력이 인정되었으며, 특히 실내실험을 통하여 높은 역병 방제효과가 인정되었다. 그러나 이 실험에서와 같이 식물의 지상부에 길항균을 살포하는 방법을 통하여 역병 방제효과를 높일 수 있을 것으로 생각된다. 이 길항균들은 갈잎 퇴비에서 분리되었기 때문에, 갈잎 퇴비에서 증식시켜 인삼재배 예정지에 투입하면, 억제형 토양 (suppressive soil) 조성을 통한 주요병해 방제가능성도 클 것으로 생각된다.