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Volume 34, Issue 8
Displaying 1-7 of 7 articles from this issue
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Osamu Kimura, Toshio Kawashima1987 Volume 34 Issue 8 Pages 325-330
Published: October 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIt is well known that large thermal stresses arise in a ceramic-metal joint because of thermal expansion mismatch. To avoid fracture of a joint, therefore, a ceramic with a smaller thermal expansion coefficient than metal has been recommended. The joint is called a "compressive joint, because it is believed that only compressive stresses arise in the ceramic part. A finite element calculation, however, has shown that a large tensile stress acts even in a ceramic part of a compressive joint. The aim of this study is to clarify stress distribution in a compressive joint by solving analytically the stress equation of the joint
We have dealt with a special joint in which the elastic constants of the ceramic are assumed to be the same as those of the metal, for convenience. The calculated tensile stress agrees fairly well withthat obtained by the finite element method and also the stress distributions by both the methods are more or less the same.View full abstractDownload PDF (345K) -
Shinjiro Tashiro, Yukio Oikawa, Hideji Igarashi, Kiyoshi Okazaki1987 Volume 34 Issue 8 Pages 331-336
Published: October 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSLead titanate ceramics modified by (Bi, Na) as A site ion in the perovskite structure were fabricated by a conventional firing. Partial substitution to that ceramics by the 3rd component such as Pb(Mg, Nb)O3 or Pb(Fe, Nb)O3 was also investigated. Their lattice parameters, dielectric constants, piezoelectric constants and elastic constants were measured as a function of PbTiO3 content.
Some compositions with low relative permittivity (εs??200), high Curie point (Tc??390°C) and with high anisotropy in electromechanical coupling coefficient (kt/kp-6) were found among PbTiO3-(Bi1/2Na1/2)TiO3-Pb(Fe1/2Nb1/2)O3 system ceramics. Piezoelctric anisotropy was discussed on the basis of the tetragonality of crystal and the elastic properties of the poled ceramics.View full abstractDownload PDF (360K) -
Tsuneyuki Ide, Kazunori Nakano, Kennichi Takagi1987 Volume 34 Issue 8 Pages 337-343
Published: October 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe liquid phase sintering of an Fe-6 wt%B-(38-53) wt%Mo ternary alloys is studied by means of DTA, dilatometric measurements, microstructural observations and transverse rupture testing. Effects of Mo content on the liquid phase sintering are discussed. Also, the relationship between the sintering mechanisms and transverse rupture strength of Fe-6 wt%B-48 wt%Mo alloy is discussed.
The results can be summarized as follows: The liquid phase sintering of the alloy is accomplished by the formation of two liquid phases produced by two different reactions. As the Mo content increases, the temperature range of the first reaction, γ-Fe+Fe2B→L1, falls slightly and the amount of L1 decreases. On the other hand, the temperature range of the second reaction, γ-Fe+Mo2FeB2→L2, rises up to 1282°C with an attendant increase in the amount of L2.View full abstractDownload PDF (3361K) -
Masahide Fukuda, Nobujiro Tsuchiya, Hisashi Suzuki1987 Volume 34 Issue 8 Pages 344-348
Published: October 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe purpose of this study is to describe, whether the life time of WC-Co cemented carbide tools for hot glasses is poor or not, as expected, even in the application in inert atmospheres. The interfacial reaction between WC-Co cemented carbide and two sorts of glasses, that is, generally known flint and crown glasses, was studied at 1023-1223 K in Ar of 0.1 MPa. It was found that the flint glass reacted sharply with binder and WC phases in cemented carbide, mostly with binder phase in the early stage of reaction; on the other hand, the crown glass never reacted. In case of the former, pore formation and precipitation of Pb phase, etc. were observed inside the glass near the interface, owing to the reaction as above. It was suggested that the life time of cemented carbide tools for flint glass can be improved, when the alloy having low carbon, low cobalt and fine carbide grains was used.View full abstractDownload PDF (5828K) -
Kazuhiko Majima, Takahiro Isono, Keiichiro Shoji1987 Volume 34 Issue 8 Pages 349-354
Published: October 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe effect of an (α+β)-quenching on the mechanical properties of sintered Ti-(2-6) wt%Fe alloys was investigated, and the results obtained are summarized as follows: The remarkable improvement of the mechanical properties ofsintered Ti-Fe alloys was observed by both the (α+β)-quenching from the temperature being 50 K below β-transus and from 913 K being 50 K above the eutectoid reaction, and the well refined microstructure was observed in both of the above mentoned two cases. The mechanical properties of Ti-4 wt% Fe specimen quenched from both of the above mentioned (α+β)-regions are also confirmed to be comparable with those of HIP'ed Ti-6A1-4V alloy.View full abstractDownload PDF (3627K) -
Kazuhiko Majima, Takahiro Isono, Keiichiro Shoji1987 Volume 34 Issue 8 Pages 355-360
Published: October 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe effect of an (α+TiFe) -tempering on the static tensile properties of sintered Ti-Fe binary alloys was investigated in relation to the holding time in the (α+TiFe)-region, and the results obtained are summarized as follows. The unexpected increment of elongation was observed during the (α+TiFe)-tempering for both the two (α+β)-quenched Ti-2 wt% and 4 wt% Fe sintered alloys, and the brittleness was not noticed, where the precipitation of TiFe was not detected by SEM observation and X-ray diffraction analysis. It was also confirmed by the X-ray diffraction analysis that the iron content in the β-phase shifted from 11-12 wt% for the as (α+β)-quenched specimen to 14-15 wt% for the specimen (α+TiFe)-tempered after (α+β)-quenching.View full abstractDownload PDF (3986K) -
Masaru Nakayama, Hiroshi Ito, Masaharu Shiroyama, Ken Sato1987 Volume 34 Issue 8 Pages 361-365
Published: October 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe sintered iron compacts will be able to be applied to selflubricating porous bearing, filter and metallic mold for casting, etc., because they have useful porosity. However, they do not have oxidation resistance, wear resistance and good mechanical properties. The chemical vapor deposition process (CVD process) is expected to give them good oxidation resistance and wear resistance. In this paper, the properties of the porous sintered iron compacts coated with TiC and Al2O3 by CVD process were investigated. The results obtained are as follows:
The CVD coatings of the porous sintered iron compact are thinner from the surface forward the inside. The TiC coatings are smooth throughout the sintered compact, while the laminated coatings of TiC and Al2O3 are smooth in the surface part and granular toward the inside. The granular products on coatings are Al2O3. The hardness and the transverse rupture strength of the porous sintered iron compacts are remarkably increased and the intercommunicating porosity is decreased by the CVD treatment. The oxidation resistance is improved when the laminated coating of TiC and Al2O3 is repeated more than twice. The transverse rupture strength is not decreased and the intercommunicating porosity is decreased by oxidation.View full abstractDownload PDF (3547K)
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