All issues
Volume 29, Issue 4
Displaying 1-7 of 7 articles from this issue
- |<
- <
- 1
- >
- >|
-
[in Japanese]1982 Volume 29 Issue 4 Pages 123-126
Published: June 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (3384K) -
Kazuhiko Majima, Yoshio Sohama1982 Volume 29 Issue 4 Pages 127-132
Published: June 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe reaction process of Ti and Ni during sintering process of the Ti-50 at%Ni binary mixed powder compacts was investigated by the model experiment using the synthetic compacts of φ300 μm Ti wire and carbonyl Ni powders, and also the dimensional changes were examined by the dilatometric method both in the press direction and that perpendicular to it.
The results obtained are as follows: The width of growth layers of intermetallic compounds, such as Ti2Ni, TiNi and TiNi3 produced in the press direction by the interdiffusion between Ti and Ni during sintering was thick, while in the direction perpendicular to it, it was thin, and some pores which are thought to he one of the main factors for the expanding phenomenon were observed in the Ni side of the interface between Ti wire and carbonyl Ni powders. On the other hand, the anisotropy of dimensional change was observed by the dilatometric method; i.e., the continuous shrinkage in the press direction and the great expansion especially in the temperatures higher than 955°C of eutectic reaction in the direction perpendicular to it. Judging from the above mentioned results of model experiment, it was confirmed that this anisotropy of dimensional change was deeply related to (1) the contracting phenomenon due to the appearance of thick layer of the intermetallic compounds in the press direction, and (2) the expanding phenomenon due to a reaction between the eutectic liquid and the intermetallic compounds being greater in the direction perpendicular to it where the width of Ti2Ni phase contacting with the eutectic liquid is thin.View full abstractDownload PDF (5592K) -
Masaru Yokota, Izuru Daikoku, Hiroyasu Mitani1982 Volume 29 Issue 4 Pages 133-138
Published: June 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSSome mechanical properties of copper alloy infiltrated iron powder compacts have beeninvestigated.The infiltrants were pure copper, copper alloys containing up to 8wt%Fe, Ni or Mn and a copper alloy containing 2wt%Fe, Ni and Mn. The iron skeletons were used as green compacts and sintered compacts. In addition, the effect of heat treatments on the mechanical properties of the infiltrated specimen has been investigated. The results obtained areas follows:
(1) Tensile strength of the copper infiltrated specimen increased rapidly with increasing infiltration time, and showed the maximum value at about 5 minutes infiltration. Beyond about 10 minutes it increased gradually with increasing infiltration time. Tensile strength of the Cu infiltrated iron green compacts was higher than that of the pre-sintered and Cu infiltrated iron powder compacts.
(2) The addition of up to about 4wt%Ni or Mn to the Cu infiltrant was superior to that of Fe to the Cu infiltrant for the purpose of preventing the surface pitting of the infiltrated specimen.
(3) The effect of various heat treatments after the infiltration and the water quenching of the infiltrated specimen on the mechanical properties has been determined. In general, the aging at 480°C for 30 minutes is desirable for improving the tensile strength, but the furnace cooling or the aging at 700°C for 20 minutes is recommendable for improving the ductility of the products. In addition, the Cu alloy infiltrated iron powder compacts aged at 700°C for 20 minutes showed a comparatively high tensile strength.View full abstractDownload PDF (4903K) -
Shiro Kohara, Kiyohiko Tatsuzawa1982 Volume 29 Issue 4 Pages 139-145
Published: June 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSMechanical properties of Fe-Cu-Ni alloys sintered by using the iron powder plated with nickel and copper were investigated. These sintered alloys showed higher tensile strength and elongation than those of conventional Fe-Cu-Ni alloys sintered with mixed powder. Values of the tensile strength and the elongation of these sintered alloys can be altered in wide range by heat treatments after sintering, that is, quenching and aging. Also it can be expected that the tensile strength of the same level as the Fe-Cu-Ni wrought materials, and the elongation of two times larger than that of the wrought alloys are attainable, when the porosity of these sintered alloys is reduced to several per cent.
The sintered alloys showed the microstructure consisted of two regions. The interglanular region where copper and nickel homogeneously diffused forms a kind of skeleton of Fe-Cu-Ni alloy. However, the inside region of large iron particles remains as pure iron after sintering. This composite structure gives the high tensile strength and the large ductility of Fe-Cu-Ni alloys sintered with plated powder.View full abstractDownload PDF (3121K) -
Keijchi Katayama, Tokuji Akiba, Giichi Sudoh, Masasuke Takata, Hiroaki ...1982 Volume 29 Issue 4 Pages 146-150
Published: June 25, 1982
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe effects of addition of Nb2O5 on rutile have been investigated by electrical measurements, XRD and SEM. The amount of additive and sintering temperatures affect greatly properties of sintered bodies. The specimens with small amounts of Nb2O5 sintered at high temperatures show the inhibition of sintering and the increased electrical conductivity. These phenomena were explained in terms of the principle of controlled valency.View full abstractDownload PDF (1417K) -
Ryuzo Watanabe, Yoshimichi Masuda1982 Volume 29 Issue 4 Pages 151-153
Published: June 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe relation between grain and pore structures in the final stage-sintering of metal powders is discussed in terms of the pinning effect of the residual pores against grain boundary migration. It is shown that Zener's relation holds between the grain size and the pinning force of the pores (oc porosity/pore size) when the porosity is less than 10% and the grain growth is in the steady-state. More thorough study about the conditions for the validity of Zener's relation is considered to be required to make an effective control of the microstructures of the sintered metals.View full abstractDownload PDF (197K) -
[in Japanese]1982 Volume 29 Issue 4 Pages 154-158
Published: June 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (363K)
- |<
- <
- 1
- >
- >|