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Volume 47, Issue 10
Displaying 1-16 of 16 articles from this issue
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Akihiko Kimura, Hiroshi Kimura1983 Volume 47 Issue 10 Pages 807-813
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCarbon tends to suppress the grain boundary fracture (GBFR) of α-iron, which is promoted by the segregation of phosphorus and other impurities to grain boundaries. This effect of carbon is due to its grain boundary segregation. It is shown in the present paper that the same effect of carbon is observed when hydrogen is the promoter of GBFR. Iron specimens with and without carbon addition are tensile tested while being charged with hydrogen electrolytically at low temperatures. A specially prepared high purity iron fractures along grain boundaries after a few per-cent elongation when tested during hydrogen charging, otherwise it is completely ductile. The same iron is ductile even under hydrogen charging, if it is doped with carbon of about 20 mass ppm. The carbon effect is further investigated with fine grained specimens made from a commercial high purity iron (J-M iron). Tests are performed on as-quenched and on aged specimens with precipitates of ε-phase and Fe3C. The result shows that carbon segregated grain boundaries has the effect to prevent GBFR.View full abstractDownload PDF (1617K) -
Kazuto Tokumitsu, Akihiro Tanaka, Hiromitsu Ino1983 Volume 47 Issue 10 Pages 814-819
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of atmosphere on the crystallization process of amorphous Pd80Si20 was investigated by X-ray diffraction Mössbauer effect and Auger electron spectroscopy. Bulk of the amorphous specimen was stable for aging at 473 K both in vacuum and in silicon oil. The crystallization to the fcc solid solution phase occurred only in the surface region (<1 μm) even in case of aging in silicon oil. It was shown that a Si poor and Pd rich region was formed between the surface and the bulk of the amorphous specimen as a result of the formation of Si oxide at the surface. It was suggested that the formation of the fcc phase is enhanced in this region.View full abstractDownload PDF (842K) -
Shigeo Sugawara, Jirô Watanabé1983 Volume 47 Issue 10 Pages 820-824
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe net rates of dissolution at dislocation sites on the Cu (111) surface etched in the Young’s solution containing 1 kmol·m−3(NH4)2S2O8, 6 kmol·m−3NH4OH and 0.3 kmol·m−3NH4Br have been determined from the enlargements of dislocation etch pits taking account of simultaneous dissolution of matrix surface. Shapes of the etch pits formed were observed using the replica electron microscopy. After etching time of 5 s, the width and depth of the etch pits were found to increase at constant rates of \doth and \dotd, respectively, keeping the side slope unchanged. The amounts of dissolution from the matrix surface were measured by the interferometric observation of step heights which were produced at the boundary line between the masked surface and the exposed surface. It was found that the matrix surface dissolved also at constant rate \dots after 5 s etching. The net dissolution rates along dislocation line vd and the lateral one vh were estimated to be 1.7 times as large as the corresponding growth rates of etch pits \dotd and \doth, respectively. These facts show that dissolution of the matrix surface must not be neglected in describing the dissolution rates at dislocation sites. Finally, using estimated values of vd, vh and \dots, the nucleation rates of two-dimensional nuclei at dislocation sites and matrix surface were analysed to be 2.9×102 s−1 per dislocation and 8.7×106 μm−2·s−1, respectively.View full abstractDownload PDF (1839K) -
Kenji Hara, Michiaki Ikeda, Shusaku Yao1983 Volume 47 Issue 10 Pages 825-831
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCopper joints brazed with BCuP-2 brazing alloy cause remarkable local corrosion in H2S atmosphere, but the joints brazed with Cu-P brazing alloy containing zinc above about 10% don’t show this type of local corrosion. The mechanisms of the local corrosion and of protection by zinc have been investigated by corrosion testing for the component materials of brazed joints. The corrosion tests were carried out in 1%H2S atmosphere for 6.9×105 s (8 days) at 353 K. The results obtained were discussed in relation to a tendency of corrosion in the aqueous solution (1 kg/m3 Na2S, 20 kg/m3 Na2SO4).
The results investigated are summerized as follows.
(1) Copper joints brazed with BCuP-2 formed Cu-P diffusion layer, which was very easy to corrode.
(2) The corrosion rate of the Cu-P alloy was accelerated by contact with parent material of copper. The contact is the probable cause of the local corrosion.
(3) Zinc content of Cu-P-Zn diffusion layer increased with an increase in zinc content of Cu-P-Zn brazing alloy. In the case of Cu-P brazing alloy containing zinc above about 10%, Cu-P diffusion layer disappeared and was replaced by Cu-P-Zn layer.
(4) The local corrosion of Cu-P alloy joints soldered with Sn-40%Pb solder was remarkable, but not observed for Cu-P alloy joints containing zinc only 0.6%. It was estimated that these results were the same as copper joints with Cu-P or Cu-P-Zn brazing alloys.
(5) The mechanism of the local corrosion and of protecting the corrosion could not be explained by the theory of wet corrosion.View full abstractDownload PDF (1511K) -
Sumiko Sanuki, Toshio Izaki, Hiroshi Majima1983 Volume 47 Issue 10 Pages 832-837
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe stripping of Fe3+ extracted in organic phase with Versatic Acid 10 was investigated. Principal results obtained are as follows;
H2SO4 was found to be the most reactive stripping agent among H2SO4, HCl and HClO4 when the stripping rates were compared at the same pH level. By introducing SO2 into the stripping reactor, the stripping rates were greatly increased in all acidic solutions. This is due mainly to the reduction of Fe3+ stripped from an organic phase to Fe2+ in an aqueous phase. The lowering of pH in the aqueous phase caused by the dissolution of SO2 may assist the acceleration of stripping process. When the stripping was made by using HCl or HClO4 aqueous solution, the stripped species were almost reduced to 100% Fe2+. On the other hand, the percentage of Fe3+ in a stripped aqueous H2SO4 solution increased with the lowering of initial pH value of stripping solution. The enhanced stripping rate may be attributed to the shift of equilibrium based on the rapid reduction of Fe3+ to Fe2+ in an aqueous phase.View full abstractDownload PDF (922K) -
Sumiko Sanuki, Toshio Izaki, Hiroshi Majima1983 Volume 47 Issue 10 Pages 838-843
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe reduction stripping of Fe(III) extracted with D2EHPA and LIX 65N by aqueous solutions of HCl, H2SO4 and HClO4 was investigated in the presence of SO2. It was found that the stripping reaction of Fe(III) from organic phases containing either D2EHPA or LIX 65N was greatly enhanced by the reducing function of SO2. Both HCl and H2SO4 were effective acids to strip Fe(III) extracted with D2EHPA, whereas H2SO4 was most effective to strip Fe(III) extracted with LIX 65N. The increase in partial pressure of SO2 resulted in the acceleration of rate of reduction of Fe3+ stripped from organic phase containing D2EHPA, while the rise of temperature was found to be the most important to reduce Fe3+ stripped from organic phase containing LIX 65N by H2SO4.View full abstractDownload PDF (815K) -
Katsuyoshi Naganuma1983 Volume 47 Issue 10 Pages 844-849
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe method of emission spectrometric determination of in-depth concentration of element in diffusion layer by using a Grimm lamp was studied. Copper diffused layers on nickel plates were used as a sample for establishing the method. The intensity-time curves for the Cu-Ni diffusion layer do not exactly represent the relations between the concentration and the depth, because first, the sputtering rate changes with the concentration of nickel and second, the intensities of CuI (319.41 nm) and NiI (319.08 nm) lines, and therefore, the intensity ratio change with the discharge time even for a homogeneous alloy. Working curves were prepared by using a series of alloy standard samples at every ten seconds of discharge time. Concentrations in the Cu-Ni diffusion layer were determined by using the working curve of corresponding discharge time. The concentrations were obtained as average values of about 2 μm range in depth. The sputtering rates at different discharge times were determined by using its relation to nickel concentration. The sputtered depth in the Cu-Ni diffusion layer for t seconds of discharge time is given by calculating the sum of the sputtering rates during the discharge time. The calculated depth for 420 seconds of discharge time was 18.7 μm and its actual depth was 18 μm. For Au-3 mass%Zn and pure Au layer evaporated on GaP plate, intensity-time curves of GaI (294.36 nm), PI (177.49 nm), AuI (242.79 nm) and ZnI (481.05 nm) lines obtained by emission spectrometry showed more exactly in-depth distributions than those by an ion microprobe analysis, because of less matrix effect.View full abstractDownload PDF (721K) -
Shingo Matsui, Kazuo Imamura, Akio Era1983 Volume 47 Issue 10 Pages 850-858
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe rate of aluminum extraction from hydrochloric acid solution with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester was studied. Two phases in a conical flask were mixed by shaking at 298 K. The initial aluminum concentration in the aqueous solution was chosen to be 2 mol/m3 so as to minimize the variation of pH during the extraction reaction. Extractant concentrations were changed from 0.05 to 1.5 kmol/m3 and pH was varied from 0.4 to 2.0.
The extraction rate was found to be of the first order with respect to the aluminum concentration in the aqueous phase. A different dependence of the extraction rate on pH and the extractant concentration was observed in the following regions: (1) When pH is below 1 or when the extractant concentration is lower than 0.2 kmol/m3, the extraction rate is of −1 order of hydrogen ion concentration in the aqueous phase but is little dependent on the extractant concentration. (2) When pH is above 1 and the extractant concentration is higher than 0.2 kmol/m3, the extraction rate is of 1.5 order of the extractant concentration, and as the extractant concentration increases, the dependence on the hydrogen ion concentration in the aqueous phase varies from −1 to −2.5 order.
Detailed consideration of the experimental results and numerical analysis with computor elucidate that there are two paths in the extraction mechanism of this system. The first path is expected to be a series of reaction from Al3+ ion and is shown as follows:
(This article is not displayable. Please see full text pdf.)
The second one is a path from AlOH2+, as is shown with the following reactions:
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (1125K) -
Iwao Katayama, Toshiteru Matsuda, Zensaku Kozuka1983 Volume 47 Issue 10 Pages 858-862
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEmf measurements of the following galvanic cells with ZrO2+CaO solid electrolyte were carried out to determine the activity of Fe3O4 in the spinel type solid solutions of Fe3O4-CoFe2O4 coexisting with Fe2O3 in the temperature range between 1100 and 1300 K in the whole composition range,
\ oindentI (−)Pt/Fe3O4, Fe2O3/ZrO2+CaO/air/Pt(+)
\ oindentII (−)Pt/(Fe3O4)x(CoFe2O4)1−x, Fe2O3/ZrO2+CaO/air/Pt(+).
\ oindentThe activity of Fe3O4 derived from the emf values showed small negative deviations from Raoult’s law in the whole composition range and obeyed Henry’s law in the range between xFe3O4=0 and 0.4.View full abstractDownload PDF (683K) -
Kazuyuki Ogawa, Masatoshi Fukamachi, Yoshikuni Kawabe1983 Volume 47 Issue 10 Pages 863-867
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStructure of 3.5 GPa grade maraging steel having the composition of 10%Ni-18%Co-14%Mo-58%Fe was investigated by transmission electron microscopy. The structural differences were compared between the specimens with and without a thermomechanical treatment. Two kinds of intermetallic compounds (Ni3Mo and Fe2Mo) were observed to precipitate in the peak-aged specimens. Distribution of precipitates was examined with the dark-field image and the lattice image techniques. Average sizes of precipitates in the specimens with and without the thermomechanical treatment are 5.8 nm and 16.7 nm, respectively. The density of precipitates is of the order of 1023 m−3.View full abstractDownload PDF (1102K) -
Hiroshi Mabuchi, Yutaka Nakayama1983 Volume 47 Issue 10 Pages 867-872
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPolycrystalline specimens of magnesium have been deformed in tension at 473 K, and the behaviors of grain boundary deformation were investigated mainly by optical microscopy. Particular attension has been paid to the formation of a band region of grain boundary, which is a cell region formed by the localized grain boundary migration (i.e. bulging mechanism) and the polygonization in a region adjacent to the grain boundary. Results obtained are summarized as follows.
(1) The specimens had a strong preferred orientation with the basal planes lying parallel to the tensile direction (rolling direction), therefore the Schmid factor for basal slip is small. At 473 K, however, basal slips have been activated in consequence of the relative difficulty in occurrence of non-basal slip and twinning.
(2) When the orientation relationship between adjoining grains is chosen in such a way that the crystal rotation due to basal slips is opposed to each other, the band region of grain boundary forms preferentially.
(3) Therefore, these results indicate that the additional stress concentration at grain boundary induced by deformation of grains is a dominating factor in the formation of the band region.View full abstractDownload PDF (1769K) -
Hisashi Suzuki, Goroh Itoh, Katsumi Koyama1983 Volume 47 Issue 10 Pages 873-878
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA basic study has been made on the heat-resistance of chill-cast Al-4 mass%Cu-(0-6) mass%Mn alloys, by examining hardness and structural changes mainly at an over-aged state. The cooling rate during solidification was estimated at about 103 K·s−1, and nearly all of Mn atoms seemed to dissolve in the supersaturated solid solution for chill-cast specimens containing Mn up to 4%. It was revealed that softening due to over-aging became markedly suppressed as Mn content increases for specimens pre-treated (homogenized at 793 K for 0.6 ks, water-quenched, aged at 473 K for 60 ks) and then subjected to the over-aging treatment at 623 K. This was attributed to the fact that the number of ternary precipitates formed during over-aging increases with increasing Mn content, and that these precipitates did not easily coarsen due to the low diffusivity of Mn atoms. Alloys containing Mn more than 2% were considered to show superior heat-resistance to that of 2219 alloy. Aging at 473 K for 60 ks without homogenization was a more effective pre-treatment for suppression of softening in high Mn alloys.View full abstractDownload PDF (1609K) -
Hakaru Masumoto, Naoji Nakamura1983 Volume 47 Issue 10 Pages 879-884
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMeasurements of the strain gage factor Gf, the electrical resistivity ρ at temperatures from 293 to 1273 K, the temperature coefficient of electrical resistivity Cf and the thermo-emf relative to copper Emf, and X-ray diffraction were carried out for the Fe-15%Cr-10∼40%Co+0∼40%Ni alloys reduced 98% in sectional area by cold-drawing.
The values of Gf of the Fe-Cr-Co-Ni quaternary alloys are generally small as compared with those of Fe-15%Cr-Co ternary alloys. The maximum value shifts to the lower side of cobalt content and decreases with increasing Ni content. The minimum and the maximum of Gf appear in the alloys added 10∼15% and 20∼25%Ni, respectively. Gf in the vicinity of the composition range where the maximum appears is a little increased only in the composition range of 25∼30%Co, but the composition dependence of Gf is slightly larger than that of Fe-15%Cr-Ni ternary alloys. Both the values of ρ and Emf show the minimum and Cf the maximum, respectively, in the alloy added 15%Ni. The above abnormalities of the gage characteristics are closely related to the coexistence of the α′ phase (bcc) caused by the strain-induced transformation and the γ phase (fcc) scarecely changed by cold-working. Moreover, the workability deteriorates in alloys with lower Ni content due to the phase changes of γ→α+ε at lower temperatures and subsequently α′ induced by drawing. The alloys with higher Ni content show very good workability due to the single γ phase.
The gage characteristics of the typical Fe-12.6%Cr-25.0%Co-16.9%Ni alloy are: Gf=3.9, ρ=0.78 μΩ·m, Cf=6.9×10−4 K−1 and Emf=−2.0 μV·K−1. Therefore, these alloys are suitable for use as the strain gage elements in load cells and micro-strain sensors etc.View full abstractDownload PDF (807K) -
Hajime Suto, Yu-ichi Yoshizawa1983 Volume 47 Issue 10 Pages 884-890
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSArc-melted Mo with and without Ni up to 0.15 mass% and those subjected to high temperature-vacuum treatment (2×10−5 Pa, 1873 K) as well as hydrogen reduction (1973 K) were warm-worked by 80% at 1173 K and cold-rolled up to 50%. By using these materials, the effect of Ni on the recrystallization temperature of arc-melted Mo was investigated. As a result of this experiment, it was concluded that the recrystallization temperature of Mo was lowered by about 100 K per 0.15 mass%Ni. This value is about the third part of that reported by Semchyshen. Similar effect of Fe addition on the recrystallization of Mo without vacuum treatment was observed. The Auger electron spectroscopy examination showed that Ni was segregated as partial monolayer (about 1 at%Ni) to grain boundaries in Mo and promoted the grain growth during annealing.View full abstractDownload PDF (2646K) -
Shigeo Zaima, Yuzo Takatsuji, Mamoru Nakayama, Hideyuki Mizutani1983 Volume 47 Issue 10 Pages 891-896
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn this study, in order to examine the characteristics of ground surface of steel, grinding tests were experimented by using a certainshaped single-grit made of alumina under the wet as well as the dry condition. As the work material, annealed carbon steel S55C was used, and the grinding fluids used for the wet condition were of two kinds of emulsion typed fluids: one is with sulfur-containing extreme presure additive and another without additive. The characteristics of the ground surface were examined in three ways, that is, by a measuring device of groove profile, SEM and EPMA. Results obtained are as follows:
In the dry grinding, big piling up was produced on both sides of the ground surface, and many pieces of microchip were observed on the bottom part of the ground surface. Under the wet condition, the piling up and the deposits above decreased remarkably. When the extreme pressure additive was used in the wet griding, the ground surface became smooth in general, and especially smoother, when the groove of the grain flat of the grit was smoother in the beginning of the grinding. As for the residual, any quantity of alumina was not detected on the ground groove in the dry grinding, but Fe, a composition of the work material, was found to adhere to the grain flat. In the wet grinding, the ground groove was dotted with Al, a main composition of alumina toward the grinding direction. Also it was found that sulfur remaind on the ground surface when the emulsion with sulfur-containing additive was used in the grinding.View full abstractDownload PDF (1421K) -
Kiyoshi Kusabiraki, Katsuya Imai1983 Volume 47 Issue 10 Pages 896-902
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCoarsening of dendrite arm spacing in the liquid-solid region of Cu-Ni alloy during isothermal holding has been investigated by in situ observation with a high temperature microscope.
It is possible to estimate a dendrite structure in a bulk from that on the surface, because both the dendrite arm spacings are almost similar. The coarsening was confirmed to be caused by the disappearance of smaller arms and melting off of arms in a necked region. The observed mode of remelting of a small cylindrical arm is consistent with the Model I proposed by Kattamis et al. In the case of a melting off of dendrite arms in the necked region, the coarsening of dendrite structure is not explained by Model II proposed by Kattamis et al. In this case the model previously proposed by us explains it satisfactorily.View full abstractDownload PDF (1465K)
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