The mother Ni-W (1-5 wt.%) alloy billets for coated conductor substrate were fabricated by powder metallurgy process. The tensile test results for the sintered Ni-W rods showed the increase of mechanical strength and decrease of ductility with increasing W content due to the solid solution hardening. All the fracture surfaces of the tested specimens showed the typical ductile fracture mode of dimple rupture due to the local necking. The Ni-W alloy billets were made into tape by cold rolling. After the appropriate heat treatment for recrystallization, the brass texture formed by the cold rolling was converted to the complete cube texture. The in-plane and out of plane texture of the tapes estimated by x-ray pole figure were smaller than 9 degree and 7 degree, respectively. The effect of the W addition on the texture development seems not to be significant.

새로운 급속소결방법인 고주파유도가열 소결법과 펄스전류활성 소결법을 이용하여 습식 볼밀링으로 혼합한 WC-8wt.%Co분말에 60MPa의 압력과 90%의 고주파출력 또는 2800A의 필스전류를 가하여 상대밀도가 98.6% 이상인 초경재료를 2분이내의 짧은 시간에 제조하였다. 초기의 WC분말의 입도가 미세해짐에 따라 고주파유도가열 소결법과 펄스전류활성 소결법 모두 소결시간이 단축되는 경향을 보였으며 그 소결체의 결정립 크기도 감소하였다. 고주파유도가열 소결

고주파유도가열 연소합성법으로 60MPa의 기계적 압력과 고주파유도가열 장치의 총용량 (15KW)의 90%의 출력을 가해 75초의 짧은 시간에 97%이상의 상대밀도를 갖는 복합체를 제조하였으며, 제조된 시편의 미세조직 사진으로부터 선형분석법으로 측정한 의 평균 결정립크기는 각각 250nm 과 60nm 이었다. 또한 제조된 시편을 연마하여 비커스 경도계를 이용하여 기계적 특성평가를 한 결과 경도 와 파괴인성은 각각 와 이었다.

The effect of Cu content on microstructure and mechanical properties of nano-sized Cu dispersed nanocomposites was investigated. The nanocomposites with Cu content of 2.5 to were prepared by reduction and hot-pressing of powder mixtures. The nanocomposites with Cu content of 2.5 and exhibited the maximum fracture strength of 820MPa and enhanced toughness compared with monolithic . The strengthening was mainly attributed to the refinement of matrix grains. The toughening mechanism was discussed by the observed microstructural feature based on crack bridging

Aluminum based metal matrix composite reinforced with SiC particles was fabricated by the powder-in sheath rolling method. A stainless steel tube with outer diameter of 12 mm and wall thickness of 1mm was used as a sheath. Mixture of aluminum powder and SiC particles of which volume content was varied from 5 to 20vol.% was filled in the tube by tap filling and then rolled to 75% reduction at ambient temperature. The rolled specimen was sintered at 56 for 0.5hr. The tensile strength of the (SiC)/Al composite increased with the volume content of SiC particles, and at 20vol.% it reached a maximum of 100㎫ which is 1.6 times higher than unreinforced material. The elongation decreased with the volume content of O particles. The mechanical properties of the (SiC)/Al composite fabricated by the powder-in sheath rolling is compared with that of (AlO)/Al composite by the same process.ess.