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Volume 19, Issue 8
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]1973 Volume 19 Issue 8 Pages 325-334
Published: March 25, 1973
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSDownload PDF (581K) -
Hiroshi Sekito, Toshio Kaneko, Hiroshi Kuno1973 Volume 19 Issue 8 Pages 335-339
Published: March 25, 1973
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSPressure sintering processes on powder crystals of Adipic acid, β-Naphthol, Phthalic acid anhydride and Salicylic acid have been studied.
All of these processes were expressed by the equation, log(1+k1logε)=k2t+k3, which was derived assuming a viscous flow mechanism of a Bingham solid. Where ε is the porosity of the powder bed at time t.
Temperature and applied pressure dependencies of the constants k1 and k3 were studied. It was found that the effective stress on pores is proportional to the applied pressure, and the decrease of the yield stress with the temperature becomes sharp at the temperature of approximately thirty degrees below the melting-point.View full abstractDownload PDF (2177K) -
Hisashi Suzuki, Kozi Hayashi, Osamu Terada1973 Volume 19 Issue 8 Pages 340-345
Published: March 25, 1973
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe mechanism of formation of anomalous carbide (named here for the carbide occluding plate-shaped titanium carbide) in TiC-Mo2C-Ni alloy was in detail studied. The factors affecting the mean grain size of carbide in the alloy, controlled by the mean grain size of two sorts of carbides, that is, normal carbide (occluding granular titanium carbide) and the anomalous carbide were also studied.
The results obtained were as follows: (1) It was found that the anomalous carbide formed by solutionreprecipitation of titanium carbide in the localized region of TiC-Ni alloy; such a region has been formed by the non-uniform distribution of Mo2C particles due to inadequate milling. (2) Therefore, the mechanism of formation and the composition of the anomalous carbide were believed to be essentially different from those of normal carbide. (3) The mean grain size of carbides in the alloy has been explained by taking into account the mechanisms of formation of both carbides, alloy compositions and manufacturing conditions, etc.View full abstractDownload PDF (7189K) -
Hisashi Suzuki, Kozi Hayashi, Yasunori Fuke1973 Volume 19 Issue 8 Pages 346-353
Published: March 25, 1973
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe methods of revealing grain-structures of binder-phase (γ-phase) in WC-Co alloy, effects of various factors on the grain size of γ-phase, the composition changes near the grain boundary of γ-phase and the mechanical properties affected by the grain size were in detail investigated. The results obtained were as follows; (1) The grain-structure of γ-phase in WC-Co alloy was confirmed to be succesfully revealed by either chemical etching or thermal etching under a certain suitable condition. The reasons why the γ-phase grain could be revealed by these methods were discussed. The surface-pattern of as-sintered alloy was also confirmed to reflect well the γ-phase grain. (2) The grain size of γ-phase increased with increasing cobalt contents and mean grain size of WC in the alloy, and increased with decreasing carbon contents and cooling rates. (3) The grain-structure of γ-phase consisted of equiaxed grains regardless of cooling rates or cobalt contents so that any kinds of anisotropy due to solidification did not exist in the cemented carbide. (4) The region deficient in cobalt contents (or execs in WC contents) existed near γ-phase grain boundary. The amount of this segregation increased with increasing cobalt contents in the alloy and grain size of γ-phase. (5) The strength of the alloy increased, in particular in high cobalt alloy, with decreasing grain size of γ-phase.View full abstractDownload PDF (9089K)
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