巻号一覧
32 巻, 4 号
選択された号の論文の6件中1～6を表示しています
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藤浦 和夫, 渡 孝則, 加藤 昭夫1985 年 32 巻 4 号 p. 136-140
発行日: 1985/06/25
公開日: 2009/05/22
ジャーナル フリーA-15 phases in Nb-Sn-Si and Nb-Al-Si systems were prepared at 1400 or 1600°C and the superconducting transition temperatures (Tc) were measured. In Nb3Sn1-xSix, Tc decreased linearly with increasing the content of Si in samples prepared at 1400°C, but showed a maximum in samples prepared at 1600°C. Nb5Si3 was formed besides A-15 phase at both preparation temperatures, resulting in the formation of a Nb-rich A-15 phase. The Nb-rich A-15 phases had the defect structures in which Nb atoms substitute So atoms on 2a sites at 1400°C and, both Nb and Si atoms locate on 2a sites at 1600°C. In Nb3Al1-xSix system, Tc decreased with increasing the content of Si in samples prepared at 1400 and 1600°C.抄録全体を表示PDF形式でダウンロード (334K) -
宮沢 俊彦, 満田 宏通, 鳥井 秀雄, 沖中 秀行1985 年 32 巻 4 号 p. 141-144
発行日: 1985/06/25
公開日: 2009/12/04
ジャーナル フリーIn a partially stabilized zirconia ceramic (ZrO2-Y2O3 solid solution) sintered above 1600°C, a resistance to mechanical stress becomes small when it is kept at a certain low temperature, such as 200°C. The cause of the deterioration of the ceramic was found by bending strength measurement, SEM observation, x-ray analysis and thermal expansion measurement. The results are as follows:
1) The remarkable deterioration of the ceramic occurs especially between 200°C and 300°C.
2) The deterioration is due to the growth of cracks caused by the expansion of its volume, when a tetragonal phase which is metastable at room temperature transforms to a monoclinic phase.
3) The transformation occurs most intensely at about 250°C and progresses from surface to inside of the ceramic.抄録全体を表示PDF形式でダウンロード (1428K) -
三浦 秀士, 徳永 洋一1985 年 32 巻 4 号 p. 145-151
発行日: 1985/06/25
公開日: 2009/12/04
ジャーナル フリーThe sintering process and spheroidization of the pores of iron and ferrophosphorus (27 wt%P) mixed powder compacts were investigated by means of photomicroscopic examination, DTA and EPMA. The results obtained were as follows:
On sintering at higher temperatures than the eutectic temperature (1050°C), the liquid of iron-phosphorus was formed and penetrated into inherent pores in the compact. As a consequence, new large rounded pores were formed at the original location of the ferrophosphorus particles, and the size and shape of the pores became small and spherical with an increase of compacting pressure even in short-time sintering. Therefore, it was considered that the appearance of spherical pores was mainly attributed to the occurrence of a liquid phase. The α-phase sintering due to the result of the diffusion of P arround 1100°C did not show any remarkable effect on the spheroidization of the pore. A model of sintering process of iron and ferrophosphorus mixed powder compacts was proposed, using the diffusion data obtained from the model experiment. And the size of spherical pore was successfully explained by the model.抄録全体を表示PDF形式でダウンロード (6815K) -
鈴木 寿, 徳本 啓1985 年 32 巻 4 号 p. 152-157
発行日: 1985/06/25
公開日: 2009/05/22
ジャーナル フリーThe WC-(10, 20)%Co medium carbon alloys with a carbide grain-size smaller than about 0.6 μm (which is the common size in commercially available micrograined alloys) were sintered by using starting WC powder of 0.20μm and adding VC to check grain growth during sintering. The microstructure and transverse-rupture strength of the alloys were mainly studied as functions of grain-size and cobalt content, or mean free path of binder phase (λ).
The strength and hardness of micro-grained alloys with the grain-size from 0.38 to 0.55 μm, which were obtained by adding 3-5% VC in binder, increased and decreased, respectively, with increasing A. Taking an example of the HIP-ed alloy, the strength became higher and it reached the value from 3.3 to 3.9 GPa, depending on A, when the size of structural defects acting as a fracture source was deminished to the size of about 6 μm. The structural defects in micro-grained alloys were often associated with an agglomerated area consisting of CaS and CaO.抄録全体を表示PDF形式でダウンロード (4954K) -
表面変化真島 一彦, 徳田 章博, 庄司 啓一郎1985 年 32 巻 4 号 p. 158-163
発行日: 1985/06/25
公開日: 2009/05/22
ジャーナル フリーA study has been carried out on the fatigue behaviour of sintered titanium powder compact compared with the case of wrought titanium specimen. In this report, especially, the surface deformation mode was observed by Nomarsky technique by using a polarization microscope and by scanning electron microscope.
The slip band formation spreading all over the specimen surface was observed during fatigue test of wrought titanium specimen in the high cycle fatigue region, and the extrusion was also noticed in some regions of slip band. Besides the above mentioned slip band, twin formation was also recognized to have a great effect on the fatigue behaviour in the low cycle fatigue region. In the case of sintered specimen, however, only a few slip bands were observed in the limited area, during the fatigue test, and any other surface deformations were not noticed in almost all part of the specimen surface.抄録全体を表示PDF形式でダウンロード (6846K) -
破面観察真島 一彦, 徳田 章博, 庄司 啓一郎1985 年 32 巻 4 号 p. 164-168
発行日: 1985/06/25
公開日: 2009/05/22
ジャーナル フリーA fractographic study has been made on the fatigue fracture behaviour of sintered titanium compact compared with the case of wrought titanium specimen.
The fractograph of wrought titanium specimen showed the typical fatigue crack propagation mode, namely, a crack nucleation along the active slip plane oriented at 45°to the applied stress axis (stage I), a crack propagation normal to the stress axis accompanied with striations and tire-tracks (stage II), and the dimple pattern owing to the final fracture (stage III). The similar fatigue crack propagation mode composed of the above mentioned three stages was also recognized in a sintered titanium specimen, however, in this case, the river pattern was noticed in any three crack propagation stages.
Owing to the much more brittleness than expected from the oxygen content in P/M specimen, the fatigue ratio of 0.26 for the P/M Ti specimen is confirmed to be extremely low, compared with the value of 0.48 for I/M Ti specimen.抄録全体を表示PDF形式でダウンロード (4637K)
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