Nanosized WC and WC-Co powders were synthesised by chemical vapor condensation(CVC) process using the pyrolysis of tungsten hexacarbonyl(W(CO)) and cobalt octacarbonyl(Co(CO)). The microstructural changes and phase evolution of the CVC powders during post heat-treatment were studied using the XRD, FE-SEM, TEM, and ICP-MS. CVC powders were consisted of the loosely agglomerated sub-stoichimetric WC and the long-chain Co nanopowders. The sub-stochiometric CVC WC and WC-Co powders were carburized using the mixture gas of CH-H in the temperature range of 730-85. Carbon content of CVC powder controlled by the gas phase carburization at 85 was well matched with the theoretical carbon sioichiometry of WC, 6.13 wt％. During the gas phase carburization, the particle size of WC increased from 20 nm to 40 nm and the long chain structure of Co powders disappeared.

The microstructures and properties of TiC dispersed nickel-base alloy were studied in this work. The alloy prepared by powder metallurgical processing was solution treated, 1st-aged at for 16 hours, and then 2nd-aged at for 4 hours. Microstucture of sintered specimen showed that TiC particles are uniformly dispersed in Ni base alloy. In the specimen aged at for 8 hours, the fine (Al,Ti) precipitates with round shape are observed and the very fine (Al,Ti) particles with round shape are precipitated in the specimen aged at for 4 hours. The presence of precipitates in TiC/Ni base alloy increased the hardness and wear resistance of the specimen. The hardness and wear resistance of the Ni-base with TiC are higher than those of conventional Ni-base superalloy X-750 because of dispersion strengthening of TiC particles. The hardness, transverse rupture strength and resistance of the specimen 2nd-aged at for 4 hours are higher than those of 1st-aged specimen due to ultrafine (Al,Ti) precipitates.

The effect of tempering temperature on the three point bending fatigue behavior of a P/M high speed steel JYPS-23 (1.28% C, 4.20% Cr, 6.40% W, 5.00% Mo, 3.10% V, bal. Fe) was investigated. The number of cycles to failure of the specimen austenitized at drastically increased with increasing tempering temperature. As tempering temperature increased from 500 to , the volume fraction and average size of carbides (MC or M6C) did not significantly changed, while hardness decreased drastically. The reduced hardness is due to the softening of matrix, which increased the resistance of the fatigue crack propagation. For a practical application, powder compacting test were also conducted with the P/M high speed steel punches tempered at 500, 580, and . The number of compacting cycles to failure of the punches also increased with increasing tempering temperature.

광 변조량, 광학밀도, 응답시간, 순환전위전류특성을 조사하여 열처리 효과에 따른 MoO3박막의 일렉트로크로믹 특성을 연구하였다. XRD 분석 결과 as-deposited MoO3박막과 350˚C 이하로 열처리된 박막은 비정질로 밝혀졌으며, 450˚C에서열처리한 MoO3박막은 결정질로 나타났다. As-deposited MoO3박막을 사용한 일렉트로크로믹 소자가 열처리된 박막을 사용한 소자에비하여 광변조 특성과 전기화학적 특성에서 좋은 일렉트로크로믹 현상을 보여주었다. MoO3박막의 열처리 온도에 따른 효과는 일렉트로크로믹 특성과 가역변색에서 광변조특성과 전기화학적 특성을 감소시키며, 열화현상을 촉진하는 것으로 나타났다.

분말야금법으로 제조된 Cu-7.5Ni-5Sn 합금의 용체화 및 시효 열처리 조건에 따른 기계적 특성의 변화를 관찰하였다. As-received 상태의 Cu-7.5Ni-5Sn 합금을 시효한 경우에는 시효 20분 후에 γ' 상의 석출에 의한 강도 증가를 나타내는데 반해, 재용체화 처리된 시편에서는 시효 수십초부터 스피노달 분해에 의한 급격한 강도의 증가를 나타내고 있다. 그러나 전체적인 인장강도는 재용체화 처리를 행한 경우에 비해 as-received 상태에서 등온 시효한 경우가 더욱 우수한 것으로 나타났다. 이러한 현상은 재용체화 처리에 의한 결정립 성장에 기인한 것으로 사료된다. As-received 상태의 Cu-7.5Ni-5Sn 합금을 장시간 시효하게 되면 결정립계에 불연속 석출물이 생성되었으며, 이러한 불연속 석출물의 생성과 성장은 열처리 조건에 영향을 받는 것으로 관찰되었으며, 합금의 최종 기계적 성질에 크게 영향을 미치는 것으로 판단된다.

The effect of β-heat treatment on th microstructure, mechanical properties and texture in the nuclear fuel cladding of Zircaloy-4 tubes was chosen at 1000, 1100 and 1200˚C, and the tubes were heat-treated by a high frequency vacuum induction furnace. Morphology of the second phase particles and α-grain of as-received tubes were markedly changed by heat treatment. The average sizes of second phase particles of as-received and β-heat treated tubes were 0.1μm and 0.076μm, respectively. However, the average sizes of second phase particles were not much changed in the β-heated temperatures. With increasing heat treatment temperatures, the 0.2% yield strength and the hoop strength were decreased because of changes in preferred orientation as will as α-plate width. Heat treated Zircaloy-4 tubes exhibited texture changes but the preferred orientation of grains still remained.