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Volume 22, Issue 4
Displaying 1-4 of 4 articles from this issue
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On the Basis of Measurement of Linear InterceptsH.E. Rose1975 Volume 22 Issue 4 Pages 121-130
Published: June 25, 1975
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn this paper the problem of the evaluation of the grain-size distribution of a spherical material embedded in a matrix is studied and a solution, based upon the measured distribution of the intercepts upon a random line cut off by the particles, is developed.
There are no limitations on the method, with respect to the type of particle-size distribution involved and, in theory, the grain size distribution may be established to any desired degree of accuracy by the use of a conversion table.
Conversion tables, sufficiently comprehensive for many practical purposes, are provided and the necessary calculations involve only a knowledge of multiplication and addition.
The work suggests that the method based upon the measurement of intercepts is experimentally simpler than is the case when the diameters of the circular intersection figures are measured. Furthermore, since the conversion tables contain fewer terms than is the case for measurements based upon diameters, the labour of application is much less than in the method based upon the measurement of the diameters of the intersection figures.View full abstractDownload PDF (407K) -
Hisashi Suzuki, Kôji Hayashi, Osamu Terada1975 Volume 22 Issue 4 Pages 131-135
Published: June 25, 1975
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSA peculiar structure was found to develop around Vickers hardness indentation in TiC base cermets, whereas it has never developed in WC base cemented carbides. Therefore, in this report, the above structure was investigated at room temperature using various cermets with various Ni, C and Mo contents and carbide grain size.
As the result, it was made clear that the structure was mainly associated with trans- and intergranular cracks of carbide under the heavy stress generated by Vickers impression, so that it was considerably influenced by various factors as shown above. The fractured structure was considered to be due to lower strength and plasticity of titanium carbide solid solution than those of WC. These results would be a help for understanding the mechanical properties of cermets.View full abstractDownload PDF (6008K) -
Isao Konda, Kumao Ôkita, Yoshikazu Tabata1975 Volume 22 Issue 4 Pages 136-140
Published: June 25, 1975
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSMedium and low-density sintered iron compacts usually have many pores, which size and shape are various. In the present paper the influence of these pores upon the fatigue strength has been investigated.
For the fatigue fracture of the medium and low-density sintered iron compacts, the following conclusions were obtained from microscopic observations.
1) Cracks generate from the pores with sharp edges and from the pseudo boundaries, without generation of slip bands in a crystal grain.
2) These cracks generate later than in the case with high density sintered iron compacts and once the cracks generate, they grow rapidly.
This tendency becomes stronger, in the case of fatigue fracture under low stress.View full abstractDownload PDF (4194K) -
Shiro Kohara, Kiyohiko Tatsuzawa1975 Volume 22 Issue 4 Pages 141-146
Published: June 25, 1975
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThe relationship between the tensile strength and porosity in sintered compacts has been investigated by using electrolytic iron powders. It was shown that the variation in the tensile strength with the porosity (or density) could be expressed separately in three stages, that is, the low density region, the middle density region, and the high density region. The relations of tensile strength and porosity in those three regions can be represented by the following forms.
For the low density region,
S=S'0-k1P (P1<P≤PO)
where S is the tensile strength, P, the porosity, PO, the green porosity, and S'0, k1 and P1, empirical constants. For the middle density region,
S=S'0 exp(-bP) (P2<P≤P1)
where S is the tensile strength, P, the porosity, and SO, b, P1 and P2, empirical constants. For the high density region,
S=(S s+k 2G-1/2)exp(-bP) (P≤P 2)
where S is the tensile strength, G, the grain size, P, the porosity, and S8, K2, b and P2, empirical constants, if the grain size can be represented as a function of porosity,
S=(Ss+k3Pa)exp(-bP) (P≤P2)
where S is the tensile strength, P, the porosity, and S8 k3, a, b and P2, empirical constants.
The empirical constants contained in the above forms were determined by the experimental results. Then, the following forms representing the relations of tensile strength and porosity for the sintered electrolytic iron powder were obtained. When the compressing pressure is 4 t/cm2, for the low density region,
S=132-495P [kg/mm2] (0.23<P≤0.27).
For the middle density region,
S=43.0 exp(-4.4P) [kg/mm2] (0.085<P≤0.23).
For the high density region,
S=(29.5+1.05G-1/2) exp(-4.4P) [kg/mm2] (P≤0.085)
where C is in mm, and
S=(29.5+62.5P0.62) exp(-4.4P) [kg/mm2] (P≤0.085).View full abstractDownload PDF (389K)
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