The microstructure and mechanical property of hot-pressed composites with a different temperature for atmosphere changing from H to Ar have been studied. When atmosphere-changed from H to Ar gas at 145, the hot-pressed composite was characterized by inhomogeneous microstructure and low fracture strength. On the contrary, when atmosphere-changed at low temperature of 110 the composite showed more homogeneous microstructure, higher fracture strength and smaller deviation in strength. Based on the thermodynamic consideration and microstructural analysis, it was interpreted that the Cu wetting behavior relating to the formation of CuAlO is probably responsible for strong dependence of microstructure on atmosphere changing temperature. The reason for a strong sensitivity of fracture strength and especially of its deviation to atmosphere changing temperature was explained by the microstructural inhomogeneity and by the role of CuAlO phase on the interfacial bonding strength.

Mechanically-alloyed NiAl powder was sintered by Spark-Plasma Sintering (SPS) process. Densification and behavior mechanical property were determined from the experimental results and analysis ,such as changes in linear shrinkage, shrinkage rate, microstructure, and phase during sintering process, Victors hardness, and transver.ie-rupture-strength (TRS). Above 97% relative density was obtained after sintering at 115 for 5 min. Crystallite size determined by the Scherrer method was approximately 50 nm. From the X-ray diffraction analysis it was confirmed that the sintered bodies were composed mainly of NiAl phase together with NiAl phase. Measured Vickers hardness and TRS value were 55510 and 139375 MPa , respectively.

A nitrogen gas atomized aluminum powder was consolidated by powder-in sheath rolling method. A pure aluminum tube with outer diameter of 12 mm and wall thickness of 1mm was used as a sheath. The aluminum tube filled with the aluminum powder, first, was cold-rolled to the thickness of 6mm for performing, and then consolidated by the cold rolling and/or subsequent hot rolling at 360, 460 and . The aluminum powder compact fabricated by the sheath rolling showed high relative density more than 0.96 at any rolling conditions. The 0.2% proof stress increased with increasing hot rolling reduction and hot rolling temperature. Tensile strength was hardly affected by change in the hot rolling reduction, whereas it decreased with increasing hot rolling temperature. The powder compact showed the large elongation when cold rolling or hot rolling reduction was large. It was found that the sheath rolling was an effective method for consolidation of aluminum powder.

A study on the improvement of the impact energy in 93W heavy alloy with a Ni/Fe ratio of 9/1 has been carried out as a function of heat treatment temperature. The obtained results were compared to that of the traditional alloy system in which the Ni/Fe ratio is 7/3 or 8/2. With increasing heat treatment temperature from 1150 to 125, the impact energy of the alloy with the Ni/Fe ratio of 9/1 is remarkably increased from 42 to 72 J, which is higher than that of traditional alloy, up to 118 and then saturated. Fracture mode was also changed from brittle W/W boundary failure to W cleavage. The temperature showing the dramatic shrinkage by dilatometric anaysis of the heavy alloy with Ni/Fe ratio of 9/1 was found to be 1483 , which is higher than that (146) of the heavy alloy with Ni/Fe ratio of 7/3. Auger Electron Spectroscopy showed that the segregation of impurities, such as S, P, and C in W/W grain boundary was considerably decreased with increasing heat treatment temperature from 1150 to l18. From the above results, it was found that the impurity segregation in W/W grain boundary played an important role on the decrease of impact properties, and the heat treatment temperature should be appropriately chosen, as considering the Ni/Fe ratio of the alloy, in order to get good impact properties.

Succinonitrile을 첨가한 새로운 에폭시 수지, diglycidyl ether of bisphenol A(DGEBA)/4, 4'-methylene dianiline(MDA)/succinonitrile(SN)계의 역학적 성질을 충격 저항실험과 응력 변형실험을 통하여 곁화반응 특성과 반응기구를 근거로 하여 고찰하였다. DGEBA/MDA계에 각각 다른 succinonitrile의 함량을 포함하는 계를 80˚C에서 1.5시간 동안 경화시킨 후 완전히 경화를 이루기 위하여 150˚C에서 1시간 동안 경화시킨 후 시험한 결과 Succinonitrile의 함량이 증가함에 따라 본 계의 충격강도는 점차적으로 증가하였으나 인장강도는 감소하였다. 그리고 Young률은 거의 일정하게 나타났으며, 신도는 succinonitrile의 함량이 10phr에서 최대값을 보였다. 본 실험으고부터 얻은 결과는 succinonitrile이 첨가됨으로써 주 사슬간의 결합길이가 연장되었기 때문임을 알았고, 적당량의 succinonitrile을 첨가함으로 에폭시 수지의 유연성이 개선됨을 알 수 있었다.

섬유보강콘크리트의 균열발생 평가는 보통 인장강도나 휨강도가 지표가 되지만 시험체 제작 과정 시에 이루어지는 양생의 영향도 좌우된다. 일반적으로 콘크리트 시험체는 20±3°C의 온도에서 수중양생을 실시한 후 강도 평가를 수행하나 실구조물은 습윤양생을 소정의 기 간 동안 실시한 후 건조 상태로 된다. 이러한 기술적인 진보가 이루어지고 있는 경향과는 달리 양생방법의 차이가 균열발생 강도에 미치는 영향 은 아직 명확하지 않고 있는 실정이다. 따라서 본 연구에서는 섬유보강콘크리트의 역학적 특성, 특히 균열발생강도에 미치는 양생방법의 영향 에 대해서 검토하였다.

Purpose of this study is investigates mechanical property of Chemically Bonded Phosphate Ceramic(CBPC). For the purpose of the investigation of mechanical property, compressive stress and length change ratio were evaluated. Evaluated results of compressive stress was shown that compressive stress increased depending on aging time. On the other hand, length change ratio decrease depending on aging time.