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Volume 47, Issue 4
Displaying 1-14 of 14 articles from this issue
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Yoshinobu Tahara, Kensuke Oki, Tetsuo Eguchi1983 Volume 47 Issue 4 Pages 279-284
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSKinetics of isochronal ordering in FeCo alloy was investigated with the measurement of temperature derivative of electrical resistivity αR. The temperature derivative of electrical resistivity caused by only the ordering or disordering, ΔαR, was estimated by eliminating other effects such as the magnetic and phonon scattering effect.
On the other hand, the kinetic equation of ordering which was derived in our previous papers from the two physical conditions was applied to the case of ordering on heating with constant velocity. The variations of ΔαR of the alloy on heating with various rates, initially quenched from various temperatures, were analyzed using the expanded rate equation. In the analysis the values of 230 kJ/mol and 0.98×1013 s−1 were taken for the activation energy and the atomic frequency, respectively. Kinetic behaviors of ΔαR were interpreted satisfactorily by the present rate equation.View full abstractDownload PDF (629K) -
Hideki Tonda, Tatsuo Kawasaki1983 Volume 47 Issue 4 Pages 284-293
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe tensile deformation behavior of zinc thin sheet crystals was investigated at the temperature range from 207 to 333 K. The tensile axis of specimens is parallel to ⟨11\bar20⟩, and the surface is parallel to {0001} (A specimens) or {00\bar10} (B specimens). B specimens showed such anomalous dependence that the yield stress increased from 11 to 13 MPa with increasing temperature, in contrast with the yield stress of A specimens decreasing from 13 to 9 MPa. The length of slip bands which appeared just after yielding decreased from 3 to 0.3 mm, and the mean free path of edge dislocations evaluated by the etch pit technique decreased from 300 to 10 μm with increasing temperature. The stress-strain curves of both A and B specimens exhibited stage I having the small work hardening ratio and then stage II having the large ratio. Stage II began just after the bundle of slip bands widening with strain filled up the whole of specimen. With increasing temperature, the strain of stage I decreased and the work hardening ratio at stage II increased rapidly.
From the standpoint of propagation of dislocation multiplication, the above results were explained by structural peculiarity of edge dislocation core, prismatic loops as barriers and dislocation reaction.View full abstractDownload PDF (1665K) -
Hideki Matsui, Hiroshi Kimura1983 Volume 47 Issue 4 Pages 294-300
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn spite of much effort, the effect of oxygen on the intergranular fracture (IGF) of iron has not been clarified as yet. There are at least three reasons for this; (i) the specimens were not pure enough, (ii) the irons so far used showed IGF at low temperatures even without oxygen, and (iii) the solubility of oxygen in iron is not known accurately.
We have prepared a high purity iron which in a form of smooth wire does not show IGF in tensile test at 4.2 K. Polycrystalline specimens of this iron was doped with oxygen; a thin oxide film was formed on the surface and a concentration (<several mass ppm) of oxygen was dissolved in equilibrium with the oxide. Thereafter, the oxide film was removed and tensile test was performed between 4.2 and 20 K. Results are as follows:
(1) As the oxygen concentration is increased by increasing the doping temperature (873, 973 and 1073 K), the elongation to fracture at 4.2 K is decreased.
(2) Specimens, which are doped with oxygen at 973 and 1073 K and fracture at 4.2 K along grain boundaries without any appreciable elongation, are completely ductile at 20 K.
(3) If well-decarburized and not doped with oxygen, a commercial high purity iron (the Johnson-Matthey iron) is more susceptible to IGF than our high purity iron.
The above results show that oxygen segregated at grain boundaries weakens the grain boundary cohesion of iron to some extent, but that the effect is not so large as considered before. Some previous researches have shown that smooth specimens fracture along grain boundaries by tension at 77 K. These results should be interpreted as due to oxide particles or to interactions between oxygen and other impurities, and not due solely to the oxygen segregated at grain boundaries.View full abstractDownload PDF (971K) -
Sumiko Sanuki, Toshio Izaki, Hiroshi Majima1983 Volume 47 Issue 4 Pages 301-307
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe role of sodium chloride in the extraction of Pb2+, Cu2+ and Zn2+ with Versatic Acid 10 from aqueous sodium chloride solution was studied. The extracted species of these metal ions from their sodium chloride solutions were found to be the same with those extracted from perchlorate or nitrate solutions. The plots of logD versus pH for Pb2+ and Zn2+ extraction simply shift towards a higher pH side with the increase in sodium chloride concentrations, while those for Cu2+ extraction exhibit the maximum pH values at a certain sodium chloride concentration. The extraction curves still show a considerably big deviation, after removing the effect of the formation of chloro-complexes of these metal ions. This suggests that the other factors except complex formation affect the extraction reactions.
The salting-out effect due to the presense of sodium chloride in an aqueous phase was examined to explain such a big deviation. The pH values at 50% extraction experimentally determined for these metal ions coincide well with those calculated by using the pH values at 50% extraction determined for the extraction of these metal ions from aqueous perchlorate or nitrate solutions and respective by-reaction coefficients, although a slight deviation is observed for Pb2+ extraction.
Based on the findings obtained by the fundamental study mentioned above, the separation of Pb2+, Cu2+ and Zn2+ from a mixed solution of these metal ions containing sodium chloride was studied. It was found that the separation of Pb2+ from Cu2+ became easier by adding sodium chloride to an aqueous phase.View full abstractDownload PDF (860K) -
Sumiko Sanuki, Toshio Izaki, Hiroshi Majima1983 Volume 47 Issue 4 Pages 308-313
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of chlorides including KCl, NaCl, LiCl, CaCl2 and MgCl2 on the extraction of Cu2+ with Versatic Acid 10 was studied to elucidate the salting-out effect due to the addition of chlorides to an aqueous phase.
The extracted species of Cu2+ with Versatic Acid 10 from aqueous chloride solutions were found to be the same with those extracted from perchlorate solutions. The extraction curves of Cu2+ from KCl solution of pH 4.0 represented in a form of logD-logaCl- plots show a simple decreasing tendency of D values with the increase in aCl-values. This indicates that the masking effect due to the formation of Cu(II) chloro-complexes is a main factor for a decrease of the extraction. On the other hand, the values of logD for the extraction of Cu2+ from other chloride solutions except KCl exhibit an increasing tendency at the higher range of logaCl- than −0.75. The increasing tendency for the Cu2+ extraction from LiCl, CaCl2 or MgCl2 solutions was found to be of the same order, while the tendency from NaCl solution was slightly weaker compared with that from the former three chlorides.
It was observed that a mutual relation existed between logK2,1 and loghMClnCMCln. The finding that the extraction of Cu2+ is directly determined by the amount of hydrated water with added chloride, suggests an importaut role of the amount of free water in the extraction of Cu2+ with Versatic Acid 10.View full abstractDownload PDF (806K) -
Itsuo Ishigami, Eiji Tsunasawa, Kyuhiko Yamanaka1983 Volume 47 Issue 4 Pages 314-321
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn equation describing the dependence of the critical quenching temperature upon size and shape of a specimen is developed as follows:
(This article is not displayable. Please see full text pdf.)
\ oindentwhere Tcf is the finishing temperature of carburizing, Tqc the critical quenching temperature, Tb and T1 the boiling temperature and the temperature of oil, respectively, V and S the volume and the surface area of a specimen, respectively and n′ the size factor. The suffix i is used to indicate a notation for a reference specimen i and the suffix j for other specimens. Iron specimens were quenched in eleven kinds of oils. Tqc was measured, and Tcf was calculated by means of the analytical method which had been previously developed. n′ was calculated to be 0.287 as a mean value. A regression analysis is carried out for the results and gives the following equations to a 17 mm×25 mm×1.75 mm iron plate used as a reference specimen i (Vi⁄Si=0.875 mm):
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\ oindentwhere T2 (K) is the characteristic temperature measured at the surface of a silver specimen (φ10 mm×30 mm), X (μm) the case depth of the iron plate quenched from 1473 K. Tqc estimated with this method agrees well with Tqc measured for S15C and SUS304.View full abstractDownload PDF (1154K) -
Akira Chiba, Takashi Saito, Keishi Yamaguchi1983 Volume 47 Issue 4 Pages 321-328
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe formation of carbide-dispersed layer (CD layer) by carburizing various vanadium steels at temperatures between 923 and 1273 K was studied, and the wear characteristics of these vanadium steels were examined.
Results obtained are as follows:
(1) A CD layer formed by carburizing below A1 point contains fine platelet V4C3 carbides in ferrite matrix. The crystal orientation relationships between ferrite and V4C3 carbide are (100)V4C3\varparallel(100)α-Fe, [010]V4C3\varparallel[011]α-Fe and [001]V4C3\varparallel[0\bar11]α-Fe, known as Baker-Nutting relationship.
(2) A CD layer grew in proportion to the square root of time, and the growth rate below A1 point was explained by a kinetic equation proposed by Wagner for the internal oxidation. The permeability for carbon in Fe-V alloys is expressed as follows;
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(3) Vanadium steels carburized and quench-tempered shows good wear resistance at both low and high sliding speeds, and a steel containing 2.3%V shows better wear resistance than SKD 11 steel. It is concluded from these results that fine-dispersed carbides are very effective in improving wear resistance.View full abstractDownload PDF (2129K) -
Sadao Watanabe, Takashi Sato, Shuji Hanada1983 Volume 47 Issue 4 Pages 329-335
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDeformability by hot rolling of Sendust with the nominal composition of 9.6% silicon, 5.4% aluminum and balance iron has been investigated as a function of hot rolling temperature and reduction per pass. It was found that under the optimum rolling conditions Sendust became ductile and was hot rolled without grain boundary cracking or cleavage cracking. The optimum rolling conditions are consistently derived from conditions of ductile deformation in tensile or bending tests at the lower strain rate region.View full abstractDownload PDF (3942K) -
Shuji Hanada, Sadao Watanabe, Takashi Sato, Sakai Ono, Osamu Izumi1983 Volume 47 Issue 4 Pages 336-342
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe brittleness of Sendust with the nominal composition of 9.6% silicon, 5.4% aluminum and the balance of iron has been studied experimentally. By high thermal stress due to temperature gradient in the crystal, cleavage cracks along {001} plane or grain boundary cracks are easily introduced during either solidification after casting or subsequent heat treatments. The {001} cleavage cracks are also formed under applied external stress. Fracture stress of hot rolled Sendust examined by bending tests is higher than that of cast one, indicating the removal of internal defects by hot rolling. The single crystal which was prepared by zone-melting, and therefore, less-stressed thermally can be bent plastically even at room temperature, showing a lack of internal defects acting as the origin of cracking.View full abstractDownload PDF (2672K) -
Akihiko Nagata, Shuji Hanada, Shoji Den, Osamu Izumi1983 Volume 47 Issue 4 Pages 343-350
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe improvement of the critical current density (JC) of a Nb-50 mass%Ti alloy in high magnetic fields by means of repeated heat treatment and cold working has been studied from a metallurgical viewpoint.
The cycle of heat treatment and working is found to be effective in improving JC. The final drawing after intermediate heat treatment enhances JC, especially in high magnetic fields. The fine dislocation network structure introduced by the final drawing after heat treatment may be responsible for the increment of JC in higher magnetic fields.View full abstractDownload PDF (2362K) -
Sadao Watanabe, Zenkichi Nakamura, Shuji Hanada, Takashi Sato, Osamu I ...1983 Volume 47 Issue 4 Pages 351-358
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDeformability by hot rolling of Sendust and magnetic properties of hot rolled Sendust have been investigated as a function of composition. With increasing silicon content at a constant aluminum content, deformability decreases, while it is not changed by increasing aluminum content at a constant silicon content. These results are qualitatively explained on the basis of mechanical tests at lower strain rates. Magnetic properties are improved by hot rolling, and especially the initial permeability is raised in the low frequency range. Molding and μi-temperature characteristics of cast and hot rolled Sendust are quite sensitive to composition. Segregation of alloying elements introduced during solidification is removed by hot rolling.View full abstractDownload PDF (1883K) -
Shin-ichi Kamada, Kokichi Hashiura, Taiji Nishizawa1983 Volume 47 Issue 4 Pages 359-364
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCarburized parts have been usually quenched twice; from above Ac3 of the core for grain refinement, then from above Ac1 for full hardening of the case. This two-step quenching often causes cracking and distortion. In the present work, the applicability of dual-phase steel to case hardening material has been investigated, because these kinds of steels generally have a fine grain size at high temperatures, so that it has been expected to skip the 1st step quenching.
1-2%Si-0.3%Cr-0.01-0.25%C steels were prepared for examining the grain size and the mechanical properties after carburizing at 950°C, quenching being made from 850°C and tempering at 150°C. It has been found that the grain coarsening in the core scarcely occurs if the steel has the two-phase structure of α+γ at the carburizing temperature. While the depth and hardness of the case are somewhat reduced by the addition of 2%Si, the core shows the outstanding strength-ductility combination characteristic of dual-phase steel.View full abstractDownload PDF (2083K) -
Munetaka Kuribayashi, Hisaki Okabayashi1983 Volume 47 Issue 4 Pages 365-372
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe influences of heat-treatment and cold-work on the mechanical properties at low temperatures of cathodically-hydrogen-charged austenitic stainless steels were investigated.
Results obtained are as follows.
(1) Austenitic stainless steels heat-treated at 1073 K exhibit hydrogen embrittlemet on a low temperature testing at 77 K.
(2) The susceptibility to low temperature hydrogen embrittlement (LTHE) of seven kinds of austenitic stainless steels, heat treated at 1073 K for 86.4 ks, can be arrenged in the following order;
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(3) In the case of SUS304, the materials which were heat-treated at 923-1223 K, especially at 1073-1173 K, exhibit the LTHE.
(4) Cold-work shows harmful effect on the LTHE.View full abstractDownload PDF (2010K) -
Hideki Tonda, Tatsuo Kawasaki1983 Volume 47 Issue 4 Pages 373-374
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (202K)
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