본 연구에서는 기계적 합금화 공정을 통하여 평균 10nm의 크기를 가지는 결정립으로 이루어지는 나노구조 Fe-Co 합금분말을 제조하였으며 제조된 합금분말을 PECS 공정으로 소결하여 벌크의 나노구조 Fe-Co 연자성 합금을 제조하고자 하였다. PECS 공정은 소결온도를 700, 800, 900과 1000˚C로 변화시키고 유지시간을 0에서 16분가지 변화시켜주며 수행하였다. PECS 공정의 나노구조 소결체 제조에 관한 효율성을 평가하였으며 소결온도와 유지시간의 변화에 따른 소결밀도와 미세구조의 변화를 관찰하여 최적의 소결조건을 찾고자하였다. 또한 각 소결조건에서 제조된 소결체들의 보자력과 포화자화값을 측정하여 자성특성을 평가하였다.

Ni-36at.%Al을 함유하는 나도 결정립의 NiAl 합금이 기계적 합금화법에 의해 제조되었다. 제조된 분말은 방전 플라즈마 소결법에 의해 만들어졌다. 상변테에 영향을 주는 인자는 냉각속도와 열처리 시간의 조건으로 논의되었다. 소결체의 상변태 거동은 시차 열분석(DSC)과 X-선 회절(XRD) 분석법에 의해 조사되었다. 미세구조는 주사전자현미경(SEM)으로 관찰되었다. 마르텐사이트 격사상수와 체적 분율은 X-선 회절분석법 중 직접비교법에 의해 계산되었다.

In order to enhance sinterability of W-Cu composites used for heat sink materials, mechanical alloying process where both homogeneous mixing of component powders and fine dispersion of minor phase can be easily attained was employed. Nanostructured W-Cu powders prepared by mechanical alloying showed W grain size ranged of 20-50 nm and were able to be efficiently sintered owing to the fine particle size as well as uniform distribution of Cu phase. The thermal properties such as electrical resistivity, coefficient of thermal expansion and thermal conductivity were evaluated as functions of temperature and Cu content. It was found that the coefficient of thermal expansion could be controlled by changing Cu content. The measured electrical resistivities and thermal diffusivities were also varied with Cu content. The thermal conductivities calculated from the values of resistivities and diffusivities showed similar tendency as a function of temperatures. However, this is in contradiction with thermal conductivities of pure W and Cu which decrease with increasing temperature.

In this study, the fabrication of /5vol.%Cu nanocomposite and its mechanical property were discussed. The nanocomposite powders were produced by high energy ball milling of and Cu elemental powders. The ball-milled powders were sintered with Pulse Electric Current Sintering (PECS) facility. The relative densities of specimens sintered at and after soaking process at were 96% and over 97%, respectively. The sintered microstructures were composed of matrix and the nano-sized Cu particles distributed on grain boundaries of matrix. The nanocomposite exhibited the enhanced fracture toughness compared with general monolithic . The toughness increase was explained by the crack deflection and bridging by dispersed Cu particles.

This study was carried out to investigate the possibility whether Metal Injection Molding (MIM) process could be applied to 95wt.%W-3.5wt.%Ni-1.5wt.%Fe heavy alloy in order to obtain an intricate shape. Methylcellulose was used in the injection molding for binder. was added in solvent substituting Fe powder and was doped on W-Ni premixed powder. When was added in solvent, the binder separation occurred for injection molding so that the matrix content was changed. Such problem was solved when was doped. In this study. the debinding process did not affect residual carbon content. The sintered microsouctures as addition methods of Fe element and the sintering temperature from to , which are around the temperature of liquid phase formation, were observed.