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Volume 36, Issue 1
Displaying 1-15 of 15 articles from this issue
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Osamu Kimura, Toshio Kawashima1989 Volume 36 Issue 1 Pages 1-6
Published: February 10, 1989
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIt is well known that large thermal stress arises in a ceramic-metal joint through thermal expansion mismatch. We have dealt with analytically a "compressive" joint in which thermal expansion coefficient of the ceramic part is smaller than that of the metal part.
In this paper, we apply the theory to other joints composed of three layers with different thermal expansion coefficients. One of them is a ceramic-metal-ceramic joint, and the other is a ceramic-metal-metal joint. The former is prepared by bonding two ceramic rods through a metal layer. The latter is also prepared by placing another metal layer between a ceramic-metal joint to diminish thermal stress. Thermal stress occurring in the ceramic part of the joints is discussed as a function of the interlayer thickness. The result is found in qualitative agreement with a finite element calculation conducted by other authors.View full abstractDownload PDF (373K) -
Shuji Wanikawa, Tohru Takeda1989 Volume 36 Issue 1 Pages 7-11
Published: February 10, 1989
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIn order to estimate mechanical alloying properties of Cr-based alloy, as the master alloy for preparing MA6000 superalloy, milling characteristics of Cr-Al-Ti-Ta-based alloy were examined by using vibration ball mill. Results were summarized as follows:
1) Best results were obtained from a milled 60 wt% Cr-based alloy. Mean particle size of this alloy was of 3.2 μm when milled for 18 ks.
2) The 60 wt% Cr-based alloy is apt to the master alloy for MA6000 superalloy, because milling charac-teristics of it are superior to those of Ni-17Al-28Ti alloy.
3) The oxygen content of the 60 wt% Cr-based alloy crushed into +100 mesh was less than 0.04 wt%, of which the value increased with decreasing particle size, and came to a value of 1.1 wt% at milled into 2.7 μm (Fsss).View full abstractDownload PDF (2638K) -
1989 Volume 36 Issue 1 Pages 11b
Published: 1989
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (23K) -
1989 Volume 36 Issue 1 Pages 11a
Published: 1989
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (23K) -
Shuji Wanikawa, Teruo Takahashi, Tohru Takeda1989 Volume 36 Issue 1 Pages 12-17
Published: February 10, 1989
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe feature of mechanical alloying of Ni-W-Mo, Cr-Al-Ti-Ta based alloy (Ex 1 : 3.2μm, Ex 2: -325 mesh, Ex 3: 20/32 mesh) and Y2O3 powders mixed for preparing MA6000 superalloy were investigated by using screw disc type ball mill. Results were summarized as follows:
1) Mean particle size of milled powder were influenced by initial particle size of Cr-based alloy powder.
2) In either case, the lattice constants of milled powder increased with the milling time, and an ultimate value was 0.358 nm. For obtaining the same value, milling time of Ex 1 and Ex 2, 3 were of over 60 ks and 84 ks respectively.
3) This value of lattice constants corresponds to the value of identical superalloy produced by arc methods.View full abstractDownload PDF (2844K) -
The Effects of Silane Treatment on the Sintering Behavior of Injection Molded Fe Powder and Fe-Si Mixed Powder CompactsJunjiro Takekawa1989 Volume 36 Issue 1 Pages 18-23
Published: February 10, 1989
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe effects of silane treatment on the sintering behavior of injection molded Fe and Fe-Si powder compacts were investigated. This treatment was done in such a manner as to coat the surface of a powder particle with the silane coupling agent, or to add it directly to the organic binder in the injection molding process. The results obtained were as follows:
It was shown that the densification of injection molded Fe and Fe-Si compacts during sintering was markedly accelerated by the silane treatment. In the sintering of injection molded Fe-Si compacts, an activating effect of the silane treatment was observed mainly in the temperature range between 1100-1180°C, where no liquid phases appeared.
As another effect, it was also shown that linear shrinkage of silane treated powder compacts during sintering occurred more isotropically than that of nontreated. The optimum quantity of the silane agent in the injection molding process of Fe and Fe-Si was about 0.2 wt%.View full abstractDownload PDF (3932K) -
Hiroyuki Ichinose, Hitoshi Igarashi1989 Volume 36 Issue 1 Pages 24-27
Published: February 10, 1989
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe contributions of volume and surface diffusion in high temperature sintering of copper were evaluated experimenta11y, using the sintering model compact developed by Ichinose and Kuczynski. A fine copper wire was plated with molybdenum, and then plated with copper, the thickness of which was varied to 3, 1 and 0.5 μm. Three wires thus treated with the same thick copper layer were twisted and then sintered in the slightly reducing nitrogen atmosphere.
In this case, the molybdenum layer acts as an inert marker. The neck boundaries were eliminated in this model compact, thus the operating diffusion mechanisms would be volume and/or surface diffusion. The aim of this experiment is as follows; if surface diffusion prevails, the neck growth rate would not be dependent on the thickness of plated copper layer, but if volume diffusion is predominant, it would be dependent on the thickness.
The observed neck growth follows Kuczynski's 5th power relation for volume diffusion. The neck growth rate is greatly dependent on the thickness of plated copper layer, and the expected value at thin layer is extremely small. In the case of 0.5 and 1 μm platedlayer, the neck growth was observed to stop in the latter stage, and the plated copper near the neck was exhausted. These results strongly support that volume diffusion controls the process. (Received February 25, 1988)View full abstractDownload PDF (1607K) -
Experiments on 3 Wire Model CompactHiroyuki Ichinose, Hitoshi Igarashi1989 Volume 36 Issue 1 Pages 28-32
Published: February 10, 1989
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSRole of grain boundaries in high temperature sintering of fcc metals such as nickel and copper, i.e., the effect of the presence or the absence of grain boundaries on neck growth still remains obscure.
In order to clarify this problem, a series of experiments were carried out on nickel, by using various model compacts. This first paper describes the experimental results on 3 wire model compact.
Neck growth follows Kuczynski's 5th power relation for volume diffusion. Rate of approach of centers of wires was proportional to time to 2/5 power. The data of neck growth and shrinkage were analyzed by volume diffusion mechanism with vacancy sink at the neck grain-boundary. The obtained frequency factor for self diffusion was about 1 cm2/sec and the activation energy about 61 Kcal/mol in both cases, which are in good agreement with the reported values for self diffusion.View full abstractDownload PDF (1417K) -
Experiments on 3 Tube Model Compact and Spool Model CompactHiroyuki Ichinose, Hitoshi Igarashi1989 Volume 36 Issue 1 Pages 33-37
Published: February 10, 1989
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIn order to eliminate neck grain-boundaries, a special 3 tube model compact was prepared. The neck growth behavior was observed on this model compact as well as on ordinary spool model compact. The obtained experimental results were analyzed and compared with those on 3 wire model compact reported in the first paper.
The neck growth on 3 tube model compact without neck grain-boundaries follows Kuczynski's 5th power relation for volume diffusion mechanism with vacancy sink at adjacent free surface.
The neck growth rate in the scale of x5/a2 (x: half width of neck, a: radius of wire) on 3 wire model compact with grain boundaries was 2.5 times faster than that on 3 tube model compact without grain boundaries, which is close to theex pected value of 2.83.
The neck growth rate on spool model compact, in which neck grain-boundaries were present, was the same as that on 3 tube model compact. This implies that grain boundaries in spool model compact are not effective sink for vacancies. The reason maybe due to strong restriction to shrinkage in spool model compact.View full abstractDownload PDF (2776K) -
Tsuneyuki Ide, Kazunori Nakano1989 Volume 36 Issue 1 Pages 38-42
Published: February 10, 1989
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe liquid phase sintering of Fe-6 wt%B-(38-53) wt%Mo-(0-10) wt%Cr alloys is studied by means of DTA, dilatometric measurements and microstructural observations. In addition, the mechanical properties of the sintered alloys are discussed. The results can be summarized as follows.
(1) With the increase of the Cr content, the temperature ranges of L1 and L2 reactions, γ-Fe+Fe2B→L1 and γ-Fe+Mo2FeB2→L2, shift to higher temperature.
(2) As the Mo content increases, the temperature ranges of the L1 and the L2 reactions rise up when the Cr content is fixed.
(3) The Cr distributes uniformly in Mo2FeB2, in the hard phases containing a small amount of Fe2B and in a ferrous binder.
(4) Transverse-rupture strength values around 2.0 GPa are obtained for the Cr content up to 5 wt%.View full abstractDownload PDF (1528K) -
Takeshi Kaneko1989 Volume 36 Issue 1 Pages 43-48
Published: February 10, 1989
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSEffect of heat-treatment in vacuo and hydrogen on ductility and tensile strength of the sintered 95.5W-3.0Ni-1.5Fe and 9l.3W-5.8Ni-2.9Fe (by wt%) heavy alloys has been studied for a high strain rate, using high speed impact tension testing machine (a constant speed type).
These materials were heated at 620-1200°C in hydrogen atmosphere and in vacuo for fixed time (about 9 hrs), respectively, and the mechanical properties of heat treated alloys were tested.
A high speed uniaxial tensile test of these alloys was carried out to obtain the relation between tensile strength and tensile speed in a range up to 13 m/s.
Also, strength and ductilities of these alloys have been measured.
These experimental results seem to suggest that the dynamic tensile strength is larger than the static tensile strength. The elongation also seems to show lower than static one with tensile speed.
The scanning electron micrographs of the fractured surfaces were also compared between the hydrogen treated specimens and the vacuum-treated specimens in order to examine the effect of hydrogen on fracture mode.View full abstractDownload PDF (2894K) -
Effect of Tool Shape on Roughness of Machined SurfaceEiichi Sentoku, Yoshio Fujimura, Takahiro Satoh1989 Volume 36 Issue 1 Pages 49-55
Published: February 10, 1989
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn recent years, many ceramics with various kinds of properties have appeared on the market. These ceramics are employed for a few mechanical and electronic parts. The purpose of this paper is to clarify the machining performance of machinable ceramics which have been newly developed. The machining performance of machinable ceramics is investigated and is discussed from view point of the relation between the flank wear of tool edge and the roughness of machined surface on the workpiece. The tools were K10 sintered carbide and CBN. In cutting tests by turning, the cutting speed was varied from 50 m/min to 200 m/min. The flank wear was measured by a tool makers microscope, and worn parts of the tools were observed with the SEM.
The results obtained are as follows:
(1) In the finish cutting for machinable ceramics, the best cutting condition was obtained as cutting speed of 50 m/min, feed 0.025 mm/rev, depth of cut 0.2 mm by tool of WC sintered carbide, and these condition for CBN tool was cutting speed of 100 m/min, feed 0.025 mm/rev, depth of cut 0.1 mm.
(2) Tool life of CBN tool was larger than WC sintered carbide.
(3) The cutting force increased at high speed cutting.
(4) The chamfer angle of -15 on the tool edge gives the best surface-finish and the long tool life.View full abstractDownload PDF (4169K) -
Toshihiko Shigematsu, Masato Ohtsuki, Kohji Watanabe, Yoshichika Bando ...1989 Volume 36 Issue 1 Pages 56-60
Published: February 10, 1989
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSBehavior of Fe1-xNix alloy catalysts during the hydrogenation of CO was studied by Mossbauer spectroscopy and X-ray diffraction analysis. The behavior depends on the crystal structure and composition of the alloy. In a case x=0, α Fe was converted into ε' Fe2.2C and χ Fe5C2, and after a long period of catalyst utilization χ Fe5C2 became a majority of the catalyst. Bcc Fe1-xNix (0<x≤0.20) was converted into ε' (Fe1-xNix)2.2C, whereas no carbides were formed from fcc Fe1-xNix (0.55≤x≤0.85). Carbon atoms solved into the fcc lattice and formed a fcc solid solution, Fe1-xNixCy. Ni was stable during the catalyst utilization.View full abstractDownload PDF (337K) -
Nobuyuki Hiratsuka, Mitsuo Sugimoto1989 Volume 36 Issue 1 Pages 61-64
Published: February 10, 1989
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSSmall-crystallite Ge-Fe-Ox films, of 0.6-1.0 μm thick, were made from Ge and Fe as the starting materials by vacuum evaporation under Po2=10-2 torr. Crystal phases and perpendicular magnetic anisotropy of these films were investigated. Two phases having small-crystallite irons and amorphous GeO2⋅Fe2O3 coexisted in these films where GeO2 contents (Ge/Ge+Fe) are in the region between 22 and 48 wt%. The films containing more than 48 wt% of GeO2 content were characterized by amorphous structure. GeO2 was inferior to P2O5 in the capability of making the iron oxide amorphous, because amorphous iron oxides were prepared by the addition of 16 wt% of P2O5. When Ge and Fe were evaporated under Po2=10-2 torr simultaneously, small-crystallite irons were accumulated in the films because of the incomplete reaction between GeO2 and FeOx on the glass substratre. The ferromagnetic properties of the films were originated in these small-crystallite irons. The perpendicular magnetic anisotropy films were prepared in the limited region from 22 to 32 wt% of GeO2 content. The perpendicular magnetic anisotropy constant (Ku) was 2×104 erg/cm3, that was less than those of BaFe12O19 film, CoFe2O4 film and amorphous GdFe alloy film. The perpendicular magnetic anisotropy seemed to be induced by the shape anisotropy of the columnar structure having small-crystallite irons.View full abstractDownload PDF (1375K) -
Yuji Katsumura, Tetsuya Mitsuda, Keiichi Kobori, Hisashi Suzuki1989 Volume 36 Issue 1 Pages 65-70
Published: February 10, 1989
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIt was previously reported by the present authors that, comparing the cutting performance of Al2O3-SiC powder ceramics tool with Al2O3-SiC whisker one, the flank wear of the former became smaller than that of the latter. Then, the study was undertaken to describe this reason, paying attention to the difference in the interfacial reaction between works and two sorts of ceramics. Diffusion couples consisting of pure nickel and ceramics were prepared in Ar at 1173-1573 K under 33 MPa, and microstructures near the interface were closely investigated.
Reaction (diffusion) layer containing an array of thin compound (Ni3Si, Ni5Si2, etc.)-layers was clearly observed inside the ceramics commonly in both ceramics. In SiC whisker (SiC(w)) added ceramics, the thickness of diffusion layer became larger, and that of compound layer and the spacing of this layer became smaller, compared with those of SiC powder (SiC(p)) added ceramics. The above phenomena in SiC(w) added ceramics were considered to be due to the fact that diffusion of Ni into ceramics was enhanced owing to the anisotropic array of SiC(w). The increase in the flank wear was assumed to be related to the phenomena.View full abstractDownload PDF (4060K)
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